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linux/arch/mips/lib/memcpy-inatomic.S

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[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Unified implementation of memcpy, memmove and the __copy_user backend.
*
* Copyright (C) 1998, 99, 2000, 01, 2002 Ralf Baechle (ralf@gnu.org)
* Copyright (C) 1999, 2000, 01, 2002 Silicon Graphics, Inc.
* Copyright (C) 2002 Broadcom, Inc.
* memcpy/copy_user author: Mark Vandevoorde
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
* Copyright (C) 2007 Maciej W. Rozycki
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
*
* Mnemonic names for arguments to memcpy/__copy_user
*/
/*
* Hack to resolve longstanding prefetch issue
*
* Prefetching may be fatal on some systems if we're prefetching beyond the
* end of memory on some systems. It's also a seriously bad idea on non
* dma-coherent systems.
*/
#if !defined(CONFIG_DMA_COHERENT) || !defined(CONFIG_DMA_IP27)
#undef CONFIG_CPU_HAS_PREFETCH
#endif
#ifdef CONFIG_MIPS_MALTA
#undef CONFIG_CPU_HAS_PREFETCH
#endif
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.h>
#define dst a0
#define src a1
#define len a2
/*
* Spec
*
* memcpy copies len bytes from src to dst and sets v0 to dst.
* It assumes that
* - src and dst don't overlap
* - src is readable
* - dst is writable
* memcpy uses the standard calling convention
*
* __copy_user copies up to len bytes from src to dst and sets a2 (len) to
* the number of uncopied bytes due to an exception caused by a read or write.
* __copy_user assumes that src and dst don't overlap, and that the call is
* implementing one of the following:
* copy_to_user
* - src is readable (no exceptions when reading src)
* copy_from_user
* - dst is writable (no exceptions when writing dst)
* __copy_user uses a non-standard calling convention; see
* include/asm-mips/uaccess.h
*
* When an exception happens on a load, the handler must
# ensure that all of the destination buffer is overwritten to prevent
* leaking information to user mode programs.
*/
/*
* Implementation
*/
/*
* The exception handler for loads requires that:
* 1- AT contain the address of the byte just past the end of the source
* of the copy,
* 2- src_entry <= src < AT, and
* 3- (dst - src) == (dst_entry - src_entry),
* The _entry suffix denotes values when __copy_user was called.
*
* (1) is set up up by uaccess.h and maintained by not writing AT in copy_user
* (2) is met by incrementing src by the number of bytes copied
* (3) is met by not doing loads between a pair of increments of dst and src
*
* The exception handlers for stores adjust len (if necessary) and return.
* These handlers do not need to overwrite any data.
*
* For __rmemcpy and memmove an exception is always a kernel bug, therefore
* they're not protected.
*/
#define EXC(inst_reg,addr,handler) \
9: inst_reg, addr; \
.section __ex_table,"a"; \
PTR 9b, handler; \
.previous
/*
* Only on the 64-bit kernel we can made use of 64-bit registers.
*/
#ifdef CONFIG_64BIT
#define USE_DOUBLE
#endif
#ifdef USE_DOUBLE
#define LOAD ld
#define LOADL ldl
#define LOADR ldr
#define STOREL sdl
#define STORER sdr
#define STORE sd
#define ADD daddu
#define SUB dsubu
#define SRL dsrl
#define SRA dsra
#define SLL dsll
#define SLLV dsllv
#define SRLV dsrlv
#define NBYTES 8
#define LOG_NBYTES 3
/*
* As we are sharing code base with the mips32 tree (which use the o32 ABI
* register definitions). We need to redefine the register definitions from
* the n64 ABI register naming to the o32 ABI register naming.
*/
#undef t0
#undef t1
#undef t2
#undef t3
#define t0 $8
#define t1 $9
#define t2 $10
#define t3 $11
#define t4 $12
#define t5 $13
#define t6 $14
#define t7 $15
#else
#define LOAD lw
#define LOADL lwl
#define LOADR lwr
#define STOREL swl
#define STORER swr
#define STORE sw
#define ADD addu
#define SUB subu
#define SRL srl
#define SLL sll
#define SRA sra
#define SLLV sllv
#define SRLV srlv
#define NBYTES 4
#define LOG_NBYTES 2
#endif /* USE_DOUBLE */
#ifdef CONFIG_CPU_LITTLE_ENDIAN
#define LDFIRST LOADR
#define LDREST LOADL
#define STFIRST STORER
#define STREST STOREL
#define SHIFT_DISCARD SLLV
#else
#define LDFIRST LOADL
#define LDREST LOADR
#define STFIRST STOREL
#define STREST STORER
#define SHIFT_DISCARD SRLV
#endif
#define FIRST(unit) ((unit)*NBYTES)
#define REST(unit) (FIRST(unit)+NBYTES-1)
#define UNIT(unit) FIRST(unit)
#define ADDRMASK (NBYTES-1)
.text
.set noreorder
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
.set noat
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
#else
.set at=v1
#endif
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/*
* A combined memcpy/__copy_user
* __copy_user sets len to 0 for success; else to an upper bound of
* the number of uncopied bytes.
* memcpy sets v0 to dst.
*/
.align 5
LEAF(__copy_user_inatomic)
/*
* Note: dst & src may be unaligned, len may be 0
* Temps
*/
#define rem t8
/*
* The "issue break"s below are very approximate.
* Issue delays for dcache fills will perturb the schedule, as will
* load queue full replay traps, etc.
*
* If len < NBYTES use byte operations.
*/
PREF( 0, 0(src) )
PREF( 1, 0(dst) )
sltu t2, len, NBYTES
and t1, dst, ADDRMASK
PREF( 0, 1*32(src) )
PREF( 1, 1*32(dst) )
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
bnez t2, .Lcopy_bytes_checklen
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
and t0, src, ADDRMASK
PREF( 0, 2*32(src) )
PREF( 1, 2*32(dst) )
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
bnez t1, .Ldst_unaligned
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
nop
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
bnez t0, .Lsrc_unaligned_dst_aligned
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/*
* use delay slot for fall-through
* src and dst are aligned; need to compute rem
*/
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Lboth_aligned:
SRL t0, len, LOG_NBYTES+3 # +3 for 8 units/iter
beqz t0, .Lcleanup_both_aligned # len < 8*NBYTES
and rem, len, (8*NBYTES-1) # rem = len % (8*NBYTES)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
PREF( 0, 3*32(src) )
PREF( 1, 3*32(dst) )
.align 4
1:
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LOAD t0, UNIT(0)(src), .Ll_exc)
EXC( LOAD t1, UNIT(1)(src), .Ll_exc_copy)
EXC( LOAD t2, UNIT(2)(src), .Ll_exc_copy)
EXC( LOAD t3, UNIT(3)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB len, len, 8*NBYTES
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LOAD t4, UNIT(4)(src), .Ll_exc_copy)
EXC( LOAD t7, UNIT(5)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
STORE t0, UNIT(0)(dst)
STORE t1, UNIT(1)(dst)
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LOAD t0, UNIT(6)(src), .Ll_exc_copy)
EXC( LOAD t1, UNIT(7)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
ADD src, src, 8*NBYTES
ADD dst, dst, 8*NBYTES
STORE t2, UNIT(-6)(dst)
STORE t3, UNIT(-5)(dst)
STORE t4, UNIT(-4)(dst)
STORE t7, UNIT(-3)(dst)
STORE t0, UNIT(-2)(dst)
STORE t1, UNIT(-1)(dst)
PREF( 0, 8*32(src) )
PREF( 1, 8*32(dst) )
bne len, rem, 1b
nop
/*
* len == rem == the number of bytes left to copy < 8*NBYTES
*/
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Lcleanup_both_aligned:
beqz len, .Ldone
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
sltu t0, len, 4*NBYTES
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
bnez t0, .Lless_than_4units
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
and rem, len, (NBYTES-1) # rem = len % NBYTES
/*
* len >= 4*NBYTES
*/
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LOAD t0, UNIT(0)(src), .Ll_exc)
EXC( LOAD t1, UNIT(1)(src), .Ll_exc_copy)
EXC( LOAD t2, UNIT(2)(src), .Ll_exc_copy)
EXC( LOAD t3, UNIT(3)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB len, len, 4*NBYTES
ADD src, src, 4*NBYTES
STORE t0, UNIT(0)(dst)
STORE t1, UNIT(1)(dst)
STORE t2, UNIT(2)(dst)
STORE t3, UNIT(3)(dst)
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set reorder /* DADDI_WAR */
ADD dst, dst, 4*NBYTES
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beqz len, .Ldone
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set noreorder
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Lless_than_4units:
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/*
* rem = len % NBYTES
*/
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beq rem, len, .Lcopy_bytes
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
nop
1:
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LOAD t0, 0(src), .Ll_exc)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
ADD src, src, NBYTES
SUB len, len, NBYTES
STORE t0, 0(dst)
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set reorder /* DADDI_WAR */
ADD dst, dst, NBYTES
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
bne rem, len, 1b
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set noreorder
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/*
* src and dst are aligned, need to copy rem bytes (rem < NBYTES)
* A loop would do only a byte at a time with possible branch
* mispredicts. Can't do an explicit LOAD dst,mask,or,STORE
* because can't assume read-access to dst. Instead, use
* STREST dst, which doesn't require read access to dst.
*
* This code should perform better than a simple loop on modern,
* wide-issue mips processors because the code has fewer branches and
* more instruction-level parallelism.
*/
#define bits t2
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beqz len, .Ldone
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
ADD t1, dst, len # t1 is just past last byte of dst
li bits, 8*NBYTES
SLL rem, len, 3 # rem = number of bits to keep
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LOAD t0, 0(src), .Ll_exc)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB bits, bits, rem # bits = number of bits to discard
SHIFT_DISCARD t0, t0, bits
STREST t0, -1(t1)
jr ra
move len, zero
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Ldst_unaligned:
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/*
* dst is unaligned
* t0 = src & ADDRMASK
* t1 = dst & ADDRMASK; T1 > 0
* len >= NBYTES
*
* Copy enough bytes to align dst
* Set match = (src and dst have same alignment)
*/
#define match rem
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LDFIRST t3, FIRST(0)(src), .Ll_exc)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
ADD t2, zero, NBYTES
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LDREST t3, REST(0)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB t2, t2, t1 # t2 = number of bytes copied
xor match, t0, t1
STFIRST t3, FIRST(0)(dst)
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beq len, t2, .Ldone
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB len, len, t2
ADD dst, dst, t2
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beqz match, .Lboth_aligned
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
ADD src, src, t2
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Lsrc_unaligned_dst_aligned:
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SRL t0, len, LOG_NBYTES+2 # +2 for 4 units/iter
PREF( 0, 3*32(src) )
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beqz t0, .Lcleanup_src_unaligned
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
and rem, len, (4*NBYTES-1) # rem = len % 4*NBYTES
PREF( 1, 3*32(dst) )
1:
/*
* Avoid consecutive LD*'s to the same register since some mips
* implementations can't issue them in the same cycle.
* It's OK to load FIRST(N+1) before REST(N) because the two addresses
* are to the same unit (unless src is aligned, but it's not).
*/
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LDFIRST t0, FIRST(0)(src), .Ll_exc)
EXC( LDFIRST t1, FIRST(1)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB len, len, 4*NBYTES
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LDREST t0, REST(0)(src), .Ll_exc_copy)
EXC( LDREST t1, REST(1)(src), .Ll_exc_copy)
EXC( LDFIRST t2, FIRST(2)(src), .Ll_exc_copy)
EXC( LDFIRST t3, FIRST(3)(src), .Ll_exc_copy)
EXC( LDREST t2, REST(2)(src), .Ll_exc_copy)
EXC( LDREST t3, REST(3)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
PREF( 0, 9*32(src) ) # 0 is PREF_LOAD (not streamed)
ADD src, src, 4*NBYTES
#ifdef CONFIG_CPU_SB1
nop # improves slotting
#endif
STORE t0, UNIT(0)(dst)
STORE t1, UNIT(1)(dst)
STORE t2, UNIT(2)(dst)
STORE t3, UNIT(3)(dst)
PREF( 1, 9*32(dst) ) # 1 is PREF_STORE (not streamed)
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set reorder /* DADDI_WAR */
ADD dst, dst, 4*NBYTES
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
bne len, rem, 1b
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set noreorder
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Lcleanup_src_unaligned:
beqz len, .Ldone
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
and rem, len, NBYTES-1 # rem = len % NBYTES
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beq rem, len, .Lcopy_bytes
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
nop
1:
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( LDFIRST t0, FIRST(0)(src), .Ll_exc)
EXC( LDREST t0, REST(0)(src), .Ll_exc_copy)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
ADD src, src, NBYTES
SUB len, len, NBYTES
STORE t0, 0(dst)
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set reorder /* DADDI_WAR */
ADD dst, dst, NBYTES
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
bne len, rem, 1b
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set noreorder
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Lcopy_bytes_checklen:
beqz len, .Ldone
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
nop
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Lcopy_bytes:
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/* 0 < len < NBYTES */
#define COPY_BYTE(N) \
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( lb t0, N(src), .Ll_exc); \
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB len, len, 1; \
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
beqz len, .Ldone; \
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
sb t0, N(dst)
COPY_BYTE(0)
COPY_BYTE(1)
#ifdef USE_DOUBLE
COPY_BYTE(2)
COPY_BYTE(3)
COPY_BYTE(4)
COPY_BYTE(5)
#endif
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( lb t0, NBYTES-2(src), .Ll_exc)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
SUB len, len, 1
jr ra
sb t0, NBYTES-2(dst)
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Ldone:
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
jr ra
nop
END(__copy_user_inatomic)
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Ll_exc_copy:
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
/*
* Copy bytes from src until faulting load address (or until a
* lb faults)
*
* When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28)
* may be more than a byte beyond the last address.
* Hence, the lb below may get an exception.
*
* Assumes src < THREAD_BUADDR($28)
*/
LOAD t0, TI_TASK($28)
nop
LOAD t0, THREAD_BUADDR(t0)
1:
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
EXC( lb t1, 0(src), .Ll_exc)
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
ADD src, src, 1
sb t1, 0(dst) # can't fault -- we're copy_from_user
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set reorder /* DADDI_WAR */
ADD dst, dst, 1
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
bne src, t0, 1b
[MIPS] R4000/R4400 daddiu erratum workaround This complements the generic R4000/R4400 errata workaround code and adds bits for the daddiu problem. In most places it just modifies handwritten assembly code so that the assembler is allowed to use a temporary register as daddiu may now be treated as a macro that expands to a sequence of li and daddu. It is the AT register or, where AT is unavailable or used explicitly for another purpose, an explicitly-named register is selected, using the .set at=<reg> feature added recently to gas. This feature is only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the workaround remains disabled, the required version of binutils stays unchanged. Similarly, daddiu instructions put in branch delay slots in noreorder fragments are now taken out of them and the assembler is allowed to reorder them itself as possible (which it does making the whole idea of scheduling them into delay slots manually questionable). Also in the very few places where such a simple conversion was not possible, a handcoded longer sequence is implemented. Other than that there are changes to code responsible for building the TLB fault and page clear/copy handlers to avoid daddiu as appropriate. These are only effective if the erratum is verified to be present at the run time. Finally there is a trivial update to __delay(), because it uses daddiu in a branch delay slot. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-23 11:43:25 +00:00
.set noreorder
[MIPS] Eleminate local symbols from the symbol table. These symbols appear in oprofile output, stacktraces and similar but only make the output harder to read. Many identical symbol names such as "both_aligned" were also being used in multiple source files making it impossible to see which file actually was meant. So let's get rid of them. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:59 +00:00
.Ll_exc:
[MIPS] Fixup copy_from_user_inatomic From the 01408c4939479ec46c15aa7ef6e2406be50eeeca log message: The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. < --- end cite --- > This patch finally implements at least a not so pretty solution by duplicating the relevant part of __copy_user. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-19 16:59:24 +00:00
LOAD t0, TI_TASK($28)
nop
LOAD t0, THREAD_BUADDR(t0) # t0 is just past last good address
nop
SUB len, AT, t0 # len number of uncopied bytes
jr ra
nop
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