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linux/arch/xtensa/lib/usercopy.S
Chris Zankel 367b8112fe xtensa: move headers files to arch/xtensa/include 
Move all header files for xtensa to arch/xtensa/include and platform and
variant header files to the appropriate arch/xtensa/platforms/ and
arch/xtensa/variants/ directories.

Moving the files gets also rid of all uses of symlinks in the Makefile.

This has been completed already for the majority of the architectures
and xtensa is one out of six missing.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Chris Zankel <chris@zankel.net>
2008-11-06 10:25:09 -08:00

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/*
* arch/xtensa/lib/usercopy.S
*
* Copy to/from user space (derived from arch/xtensa/lib/hal/memcopy.S)
*
* DO NOT COMBINE this function with <arch/xtensa/lib/hal/memcopy.S>.
* It needs to remain separate and distinct. The hal files are part
* of the Xtensa link-time HAL, and those files may differ per
* processor configuration. Patching the kernel for another
* processor configuration includes replacing the hal files, and we
* could lose the special functionality for accessing user-space
* memory during such a patch. We sacrifice a little code space here
* in favor to simplify code maintenance.
*
* 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) 2002 Tensilica Inc.
*/
/*
* size_t __xtensa_copy_user (void *dst, const void *src, size_t len);
*
* The returned value is the number of bytes not copied. Implies zero
* is success.
*
* The general case algorithm is as follows:
* If the destination and source are both aligned,
* do 16B chunks with a loop, and then finish up with
* 8B, 4B, 2B, and 1B copies conditional on the length.
* If destination is aligned and source unaligned,
* do the same, but use SRC to align the source data.
* If destination is unaligned, align it by conditionally
* copying 1B and 2B and then retest.
* This code tries to use fall-through braches for the common
* case of aligned destinations (except for the branches to
* the alignment label).
*
* Register use:
* a0/ return address
* a1/ stack pointer
* a2/ return value
* a3/ src
* a4/ length
* a5/ dst
* a6/ tmp
* a7/ tmp
* a8/ tmp
* a9/ tmp
* a10/ tmp
* a11/ original length
*/
#include <variant/core.h>
#ifdef __XTENSA_EB__
#define ALIGN(R, W0, W1) src R, W0, W1
#define SSA8(R) ssa8b R
#else
#define ALIGN(R, W0, W1) src R, W1, W0
#define SSA8(R) ssa8l R
#endif
/* Load or store instructions that may cause exceptions use the EX macro. */
#define EX(insn,reg1,reg2,offset,handler) \
9: insn reg1, reg2, offset; \
.section __ex_table, "a"; \
.word 9b, handler; \
.previous
.text
.align 4
.global __xtensa_copy_user
.type __xtensa_copy_user,@function
__xtensa_copy_user:
entry sp, 16 # minimal stack frame
# a2/ dst, a3/ src, a4/ len
mov a5, a2 # copy dst so that a2 is return value
mov a11, a4 # preserve original len for error case
.Lcommon:
bbsi.l a2, 0, .Ldst1mod2 # if dst is 1 mod 2
bbsi.l a2, 1, .Ldst2mod4 # if dst is 2 mod 4
.Ldstaligned: # return here from .Ldstunaligned when dst is aligned
srli a7, a4, 4 # number of loop iterations with 16B
# per iteration
movi a8, 3 # if source is also aligned,
bnone a3, a8, .Laligned # then use word copy
SSA8( a3) # set shift amount from byte offset
bnez a4, .Lsrcunaligned
movi a2, 0 # return success for len==0
retw
/*
* Destination is unaligned
*/
.Ldst1mod2: # dst is only byte aligned
bltui a4, 7, .Lbytecopy # do short copies byte by byte
# copy 1 byte
EX(l8ui, a6, a3, 0, l_fixup)
addi a3, a3, 1
EX(s8i, a6, a5, 0, s_fixup)
addi a5, a5, 1
addi a4, a4, -1
bbci.l a5, 1, .Ldstaligned # if dst is now aligned, then
# return to main algorithm
.Ldst2mod4: # dst 16-bit aligned
# copy 2 bytes
bltui a4, 6, .Lbytecopy # do short copies byte by byte
EX(l8ui, a6, a3, 0, l_fixup)
EX(l8ui, a7, a3, 1, l_fixup)
addi a3, a3, 2
EX(s8i, a6, a5, 0, s_fixup)
EX(s8i, a7, a5, 1, s_fixup)
addi a5, a5, 2
addi a4, a4, -2
j .Ldstaligned # dst is now aligned, return to main algorithm
/*
* Byte by byte copy
*/
.align 4
.byte 0 # 1 mod 4 alignment for LOOPNEZ
# (0 mod 4 alignment for LBEG)
.Lbytecopy:
#if XCHAL_HAVE_LOOPS
loopnez a4, .Lbytecopydone
#else /* !XCHAL_HAVE_LOOPS */
beqz a4, .Lbytecopydone
add a7, a3, a4 # a7 = end address for source
#endif /* !XCHAL_HAVE_LOOPS */
.Lnextbyte:
EX(l8ui, a6, a3, 0, l_fixup)
addi a3, a3, 1
EX(s8i, a6, a5, 0, s_fixup)
addi a5, a5, 1
#if !XCHAL_HAVE_LOOPS
blt a3, a7, .Lnextbyte
#endif /* !XCHAL_HAVE_LOOPS */
.Lbytecopydone:
movi a2, 0 # return success for len bytes copied
retw
/*
* Destination and source are word-aligned.
*/
# copy 16 bytes per iteration for word-aligned dst and word-aligned src
.align 4 # 1 mod 4 alignment for LOOPNEZ
.byte 0 # (0 mod 4 alignment for LBEG)
.Laligned:
#if XCHAL_HAVE_LOOPS
loopnez a7, .Loop1done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .Loop1done
slli a8, a7, 4
add a8, a8, a3 # a8 = end of last 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1:
EX(l32i, a6, a3, 0, l_fixup)
EX(l32i, a7, a3, 4, l_fixup)
EX(s32i, a6, a5, 0, s_fixup)
EX(l32i, a6, a3, 8, l_fixup)
EX(s32i, a7, a5, 4, s_fixup)
EX(l32i, a7, a3, 12, l_fixup)
EX(s32i, a6, a5, 8, s_fixup)
addi a3, a3, 16
EX(s32i, a7, a5, 12, s_fixup)
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
blt a3, a8, .Loop1
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1done:
bbci.l a4, 3, .L2
# copy 8 bytes
EX(l32i, a6, a3, 0, l_fixup)
EX(l32i, a7, a3, 4, l_fixup)
addi a3, a3, 8
EX(s32i, a6, a5, 0, s_fixup)
EX(s32i, a7, a5, 4, s_fixup)
addi a5, a5, 8
.L2:
bbci.l a4, 2, .L3
# copy 4 bytes
EX(l32i, a6, a3, 0, l_fixup)
addi a3, a3, 4
EX(s32i, a6, a5, 0, s_fixup)
addi a5, a5, 4
.L3:
bbci.l a4, 1, .L4
# copy 2 bytes
EX(l16ui, a6, a3, 0, l_fixup)
addi a3, a3, 2
EX(s16i, a6, a5, 0, s_fixup)
addi a5, a5, 2
.L4:
bbci.l a4, 0, .L5
# copy 1 byte
EX(l8ui, a6, a3, 0, l_fixup)
EX(s8i, a6, a5, 0, s_fixup)
.L5:
movi a2, 0 # return success for len bytes copied
retw
/*
* Destination is aligned, Source is unaligned
*/
.align 4
.byte 0 # 1 mod 4 alignement for LOOPNEZ
# (0 mod 4 alignment for LBEG)
.Lsrcunaligned:
# copy 16 bytes per iteration for word-aligned dst and unaligned src
and a10, a3, a8 # save unalignment offset for below
sub a3, a3, a10 # align a3 (to avoid sim warnings only; not needed for hardware)
EX(l32i, a6, a3, 0, l_fixup) # load first word
#if XCHAL_HAVE_LOOPS
loopnez a7, .Loop2done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .Loop2done
slli a10, a7, 4
add a10, a10, a3 # a10 = end of last 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2:
EX(l32i, a7, a3, 4, l_fixup)
EX(l32i, a8, a3, 8, l_fixup)
ALIGN( a6, a6, a7)
EX(s32i, a6, a5, 0, s_fixup)
EX(l32i, a9, a3, 12, l_fixup)
ALIGN( a7, a7, a8)
EX(s32i, a7, a5, 4, s_fixup)
EX(l32i, a6, a3, 16, l_fixup)
ALIGN( a8, a8, a9)
EX(s32i, a8, a5, 8, s_fixup)
addi a3, a3, 16
ALIGN( a9, a9, a6)
EX(s32i, a9, a5, 12, s_fixup)
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
blt a3, a10, .Loop2
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2done:
bbci.l a4, 3, .L12
# copy 8 bytes
EX(l32i, a7, a3, 4, l_fixup)
EX(l32i, a8, a3, 8, l_fixup)
ALIGN( a6, a6, a7)
EX(s32i, a6, a5, 0, s_fixup)
addi a3, a3, 8
ALIGN( a7, a7, a8)
EX(s32i, a7, a5, 4, s_fixup)
addi a5, a5, 8
mov a6, a8
.L12:
bbci.l a4, 2, .L13
# copy 4 bytes
EX(l32i, a7, a3, 4, l_fixup)
addi a3, a3, 4
ALIGN( a6, a6, a7)
EX(s32i, a6, a5, 0, s_fixup)
addi a5, a5, 4
mov a6, a7
.L13:
add a3, a3, a10 # readjust a3 with correct misalignment
bbci.l a4, 1, .L14
# copy 2 bytes
EX(l8ui, a6, a3, 0, l_fixup)
EX(l8ui, a7, a3, 1, l_fixup)
addi a3, a3, 2
EX(s8i, a6, a5, 0, s_fixup)
EX(s8i, a7, a5, 1, s_fixup)
addi a5, a5, 2
.L14:
bbci.l a4, 0, .L15
# copy 1 byte
EX(l8ui, a6, a3, 0, l_fixup)
EX(s8i, a6, a5, 0, s_fixup)
.L15:
movi a2, 0 # return success for len bytes copied
retw
.section .fixup, "ax"
.align 4
/* a2 = original dst; a5 = current dst; a11= original len
* bytes_copied = a5 - a2
* retval = bytes_not_copied = original len - bytes_copied
* retval = a11 - (a5 - a2)
*
* Clearing the remaining pieces of kernel memory plugs security
* holes. This functionality is the equivalent of the *_zeroing
* functions that some architectures provide.
*/
.Lmemset:
.word memset
s_fixup:
sub a2, a5, a2 /* a2 <-- bytes copied */
sub a2, a11, a2 /* a2 <-- bytes not copied */
retw
l_fixup:
sub a2, a5, a2 /* a2 <-- bytes copied */
sub a2, a11, a2 /* a2 <-- bytes not copied == return value */
/* void *memset(void *s, int c, size_t n); */
mov a6, a5 /* s */
movi a7, 0 /* c */
mov a8, a2 /* n */
l32r a4, .Lmemset
callx4 a4
/* Ignore memset return value in a6. */
/* a2 still contains bytes not copied. */
retw
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