linux/arch/mips/lib/memset.S

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/*
* 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.
*
* Copyright (C) 1998, 1999, 2000 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
[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
*/
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.h>
#if LONGSIZE == 4
#define LONG_S_L swl
#define LONG_S_R swr
#else
#define LONG_S_L sdl
#define LONG_S_R sdr
#endif
#define EX(insn,reg,addr,handler) \
9: insn reg, addr; \
.section __ex_table,"a"; \
PTR 9b, handler; \
.previous
.macro f_fill64 dst, offset, val, fixup
EX(LONG_S, \val, (\offset + 0 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 1 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 2 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 3 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 4 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 5 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 6 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 7 * LONGSIZE)(\dst), \fixup)
#if LONGSIZE == 4
EX(LONG_S, \val, (\offset + 8 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 9 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 10 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 11 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 12 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 13 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 14 * LONGSIZE)(\dst), \fixup)
EX(LONG_S, \val, (\offset + 15 * LONGSIZE)(\dst), \fixup)
#endif
.endm
/*
* memset(void *s, int c, size_t n)
*
* a0: start of area to clear
* a1: char to fill with
* a2: size of area to clear
*/
.set noreorder
.align 5
LEAF(memset)
beqz a1, 1f
move v0, a0 /* result */
andi a1, 0xff /* spread fillword */
LONG_SLL t1, a1, 8
or a1, t1
LONG_SLL t1, a1, 16
#if LONGSIZE == 8
or a1, t1
LONG_SLL t1, a1, 32
#endif
or a1, t1
1:
FEXPORT(__bzero)
sltiu t0, a2, LONGSIZE /* very small region? */
bnez t0, .Lsmall_memset
andi t0, a0, LONGMASK /* aligned? */
[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
beqz t0, 1f
PTR_SUBU t0, LONGSIZE /* alignment in bytes */
[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 noat
li AT, LONGSIZE
beqz t0, 1f
PTR_SUBU t0, AT /* alignment in bytes */
.set at
#endif
R10KCBARRIER(0(ra))
#ifdef __MIPSEB__
EX(LONG_S_L, a1, (a0), .Lfirst_fixup) /* make word/dword aligned */
#endif
#ifdef __MIPSEL__
EX(LONG_S_R, a1, (a0), .Lfirst_fixup) /* make word/dword aligned */
#endif
PTR_SUBU a0, t0 /* long align ptr */
PTR_ADDU a2, t0 /* correct size */
1: ori t1, a2, 0x3f /* # of full blocks */
xori t1, 0x3f
beqz t1, .Lmemset_partial /* no block to fill */
andi t0, a2, 0x40-LONGSIZE
PTR_ADDU t1, a0 /* end address */
.set reorder
1: PTR_ADDIU a0, 64
R10KCBARRIER(0(ra))
f_fill64 a0, -64, a1, .Lfwd_fixup
bne t1, a0, 1b
.set noreorder
.Lmemset_partial:
R10KCBARRIER(0(ra))
PTR_LA t1, 2f /* where to start */
#if LONGSIZE == 4
PTR_SUBU t1, t0
#else
.set noat
LONG_SRL AT, t0, 1
PTR_SUBU t1, AT
[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 at
#endif
jr t1
PTR_ADDU a0, t0 /* dest ptr */
.set push
.set noreorder
.set nomacro
f_fill64 a0, -64, a1, .Lpartial_fixup /* ... but first do longs ... */
2: .set pop
andi a2, LONGMASK /* At most one long to go */
beqz a2, 1f
PTR_ADDU a0, a2 /* What's left */
R10KCBARRIER(0(ra))
#ifdef __MIPSEB__
EX(LONG_S_R, a1, -1(a0), .Llast_fixup)
#endif
#ifdef __MIPSEL__
EX(LONG_S_L, a1, -1(a0), .Llast_fixup)
#endif
1: jr ra
move a2, zero
.Lsmall_memset:
beqz a2, 2f
PTR_ADDU t1, a0, a2
1: PTR_ADDIU a0, 1 /* fill bytewise */
R10KCBARRIER(0(ra))
bne t1, a0, 1b
sb a1, -1(a0)
2: jr ra /* done */
move a2, zero
END(memset)
.Lfirst_fixup:
jr ra
nop
.Lfwd_fixup:
PTR_L t0, TI_TASK($28)
LONG_L t0, THREAD_BUADDR(t0)
andi a2, 0x3f
LONG_ADDU a2, t1
jr ra
LONG_SUBU a2, t0
.Lpartial_fixup:
PTR_L t0, TI_TASK($28)
LONG_L t0, THREAD_BUADDR(t0)
andi a2, LONGMASK
LONG_ADDU a2, t1
jr ra
LONG_SUBU a2, t0
.Llast_fixup:
jr ra
andi v1, a2, LONGMASK