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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/lib/copy_user_64.S | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/lib/copy_user_64.S')
-rw-r--r-- | arch/x86/lib/copy_user_64.S | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S new file mode 100644 index 000000000..9dec1b38a --- /dev/null +++ b/arch/x86/lib/copy_user_64.S @@ -0,0 +1,410 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2008 Vitaly Mayatskikh <vmayatsk@redhat.com> + * Copyright 2002 Andi Kleen, SuSE Labs. + * + * Functions to copy from and to user space. + */ + +#include <linux/linkage.h> +#include <asm/current.h> +#include <asm/asm-offsets.h> +#include <asm/thread_info.h> +#include <asm/cpufeatures.h> +#include <asm/alternative.h> +#include <asm/asm.h> +#include <asm/smap.h> +#include <asm/export.h> +#include <asm/trapnr.h> + +.macro ALIGN_DESTINATION + /* check for bad alignment of destination */ + movl %edi,%ecx + andl $7,%ecx + jz 102f /* already aligned */ + subl $8,%ecx + negl %ecx + subl %ecx,%edx +100: movb (%rsi),%al +101: movb %al,(%rdi) + incq %rsi + incq %rdi + decl %ecx + jnz 100b +102: + + _ASM_EXTABLE_CPY(100b, .Lcopy_user_handle_align) + _ASM_EXTABLE_CPY(101b, .Lcopy_user_handle_align) +.endm + +/* + * copy_user_generic_unrolled - memory copy with exception handling. + * This version is for CPUs like P4 that don't have efficient micro + * code for rep movsq + * + * Input: + * rdi destination + * rsi source + * rdx count + * + * Output: + * eax uncopied bytes or 0 if successful. + */ +SYM_FUNC_START(copy_user_generic_unrolled) + ASM_STAC + cmpl $8,%edx + jb .Lcopy_user_short_string_bytes + ALIGN_DESTINATION + movl %edx,%ecx + andl $63,%edx + shrl $6,%ecx + jz copy_user_short_string +1: movq (%rsi),%r8 +2: movq 1*8(%rsi),%r9 +3: movq 2*8(%rsi),%r10 +4: movq 3*8(%rsi),%r11 +5: movq %r8,(%rdi) +6: movq %r9,1*8(%rdi) +7: movq %r10,2*8(%rdi) +8: movq %r11,3*8(%rdi) +9: movq 4*8(%rsi),%r8 +10: movq 5*8(%rsi),%r9 +11: movq 6*8(%rsi),%r10 +12: movq 7*8(%rsi),%r11 +13: movq %r8,4*8(%rdi) +14: movq %r9,5*8(%rdi) +15: movq %r10,6*8(%rdi) +16: movq %r11,7*8(%rdi) + leaq 64(%rsi),%rsi + leaq 64(%rdi),%rdi + decl %ecx + jnz 1b + jmp copy_user_short_string + +30: shll $6,%ecx + addl %ecx,%edx + jmp .Lcopy_user_handle_tail + + _ASM_EXTABLE_CPY(1b, 30b) + _ASM_EXTABLE_CPY(2b, 30b) + _ASM_EXTABLE_CPY(3b, 30b) + _ASM_EXTABLE_CPY(4b, 30b) + _ASM_EXTABLE_CPY(5b, 30b) + _ASM_EXTABLE_CPY(6b, 30b) + _ASM_EXTABLE_CPY(7b, 30b) + _ASM_EXTABLE_CPY(8b, 30b) + _ASM_EXTABLE_CPY(9b, 30b) + _ASM_EXTABLE_CPY(10b, 30b) + _ASM_EXTABLE_CPY(11b, 30b) + _ASM_EXTABLE_CPY(12b, 30b) + _ASM_EXTABLE_CPY(13b, 30b) + _ASM_EXTABLE_CPY(14b, 30b) + _ASM_EXTABLE_CPY(15b, 30b) + _ASM_EXTABLE_CPY(16b, 30b) +SYM_FUNC_END(copy_user_generic_unrolled) +EXPORT_SYMBOL(copy_user_generic_unrolled) + +/* Some CPUs run faster using the string copy instructions. + * This is also a lot simpler. Use them when possible. + * + * Only 4GB of copy is supported. This shouldn't be a problem + * because the kernel normally only writes from/to page sized chunks + * even if user space passed a longer buffer. + * And more would be dangerous because both Intel and AMD have + * errata with rep movsq > 4GB. If someone feels the need to fix + * this please consider this. + * + * Input: + * rdi destination + * rsi source + * rdx count + * + * Output: + * eax uncopied bytes or 0 if successful. + */ +SYM_FUNC_START(copy_user_generic_string) + ASM_STAC + cmpl $8,%edx + jb 2f /* less than 8 bytes, go to byte copy loop */ + ALIGN_DESTINATION + movl %edx,%ecx + shrl $3,%ecx + andl $7,%edx +1: rep movsq +2: movl %edx,%ecx +3: rep movsb + xorl %eax,%eax + ASM_CLAC + RET + +11: leal (%rdx,%rcx,8),%ecx +12: movl %ecx,%edx /* ecx is zerorest also */ + jmp .Lcopy_user_handle_tail + + _ASM_EXTABLE_CPY(1b, 11b) + _ASM_EXTABLE_CPY(3b, 12b) +SYM_FUNC_END(copy_user_generic_string) +EXPORT_SYMBOL(copy_user_generic_string) + +/* + * Some CPUs are adding enhanced REP MOVSB/STOSB instructions. + * It's recommended to use enhanced REP MOVSB/STOSB if it's enabled. + * + * Input: + * rdi destination + * rsi source + * rdx count + * + * Output: + * eax uncopied bytes or 0 if successful. + */ +SYM_FUNC_START(copy_user_enhanced_fast_string) + ASM_STAC + /* CPUs without FSRM should avoid rep movsb for short copies */ + ALTERNATIVE "cmpl $64, %edx; jb copy_user_short_string", "", X86_FEATURE_FSRM + movl %edx,%ecx +1: rep movsb + xorl %eax,%eax + ASM_CLAC + RET + +12: movl %ecx,%edx /* ecx is zerorest also */ + jmp .Lcopy_user_handle_tail + + _ASM_EXTABLE_CPY(1b, 12b) +SYM_FUNC_END(copy_user_enhanced_fast_string) +EXPORT_SYMBOL(copy_user_enhanced_fast_string) + +/* + * Try to copy last bytes and clear the rest if needed. + * Since protection fault in copy_from/to_user is not a normal situation, + * it is not necessary to optimize tail handling. + * Don't try to copy the tail if machine check happened + * + * Input: + * eax trap number written by ex_handler_copy() + * rdi destination + * rsi source + * rdx count + * + * Output: + * eax uncopied bytes or 0 if successful. + */ +SYM_CODE_START_LOCAL(.Lcopy_user_handle_tail) + cmp $X86_TRAP_MC,%eax + je 3f + + movl %edx,%ecx +1: rep movsb +2: mov %ecx,%eax + ASM_CLAC + RET + +3: + movl %edx,%eax + ASM_CLAC + RET + + _ASM_EXTABLE_CPY(1b, 2b) + +.Lcopy_user_handle_align: + addl %ecx,%edx /* ecx is zerorest also */ + jmp .Lcopy_user_handle_tail + +SYM_CODE_END(.Lcopy_user_handle_tail) + +/* + * Finish memcpy of less than 64 bytes. #AC should already be set. + * + * Input: + * rdi destination + * rsi source + * rdx count (< 64) + * + * Output: + * eax uncopied bytes or 0 if successful. + */ +SYM_CODE_START_LOCAL(copy_user_short_string) + movl %edx,%ecx + andl $7,%edx + shrl $3,%ecx + jz .Lcopy_user_short_string_bytes +18: movq (%rsi),%r8 +19: movq %r8,(%rdi) + leaq 8(%rsi),%rsi + leaq 8(%rdi),%rdi + decl %ecx + jnz 18b +.Lcopy_user_short_string_bytes: + andl %edx,%edx + jz 23f + movl %edx,%ecx +21: movb (%rsi),%al +22: movb %al,(%rdi) + incq %rsi + incq %rdi + decl %ecx + jnz 21b +23: xor %eax,%eax + ASM_CLAC + RET + +40: leal (%rdx,%rcx,8),%edx + jmp 60f +50: movl %ecx,%edx /* ecx is zerorest also */ +60: jmp .Lcopy_user_handle_tail + + _ASM_EXTABLE_CPY(18b, 40b) + _ASM_EXTABLE_CPY(19b, 40b) + _ASM_EXTABLE_CPY(21b, 50b) + _ASM_EXTABLE_CPY(22b, 50b) +SYM_CODE_END(copy_user_short_string) + +/* + * copy_user_nocache - Uncached memory copy with exception handling + * This will force destination out of cache for more performance. + * + * Note: Cached memory copy is used when destination or size is not + * naturally aligned. That is: + * - Require 8-byte alignment when size is 8 bytes or larger. + * - Require 4-byte alignment when size is 4 bytes. + */ +SYM_FUNC_START(__copy_user_nocache) + ASM_STAC + + /* If size is less than 8 bytes, go to 4-byte copy */ + cmpl $8,%edx + jb .L_4b_nocache_copy_entry + + /* If destination is not 8-byte aligned, "cache" copy to align it */ + ALIGN_DESTINATION + + /* Set 4x8-byte copy count and remainder */ + movl %edx,%ecx + andl $63,%edx + shrl $6,%ecx + jz .L_8b_nocache_copy_entry /* jump if count is 0 */ + + /* Perform 4x8-byte nocache loop-copy */ +.L_4x8b_nocache_copy_loop: +1: movq (%rsi),%r8 +2: movq 1*8(%rsi),%r9 +3: movq 2*8(%rsi),%r10 +4: movq 3*8(%rsi),%r11 +5: movnti %r8,(%rdi) +6: movnti %r9,1*8(%rdi) +7: movnti %r10,2*8(%rdi) +8: movnti %r11,3*8(%rdi) +9: movq 4*8(%rsi),%r8 +10: movq 5*8(%rsi),%r9 +11: movq 6*8(%rsi),%r10 +12: movq 7*8(%rsi),%r11 +13: movnti %r8,4*8(%rdi) +14: movnti %r9,5*8(%rdi) +15: movnti %r10,6*8(%rdi) +16: movnti %r11,7*8(%rdi) + leaq 64(%rsi),%rsi + leaq 64(%rdi),%rdi + decl %ecx + jnz .L_4x8b_nocache_copy_loop + + /* Set 8-byte copy count and remainder */ +.L_8b_nocache_copy_entry: + movl %edx,%ecx + andl $7,%edx + shrl $3,%ecx + jz .L_4b_nocache_copy_entry /* jump if count is 0 */ + + /* Perform 8-byte nocache loop-copy */ +.L_8b_nocache_copy_loop: +20: movq (%rsi),%r8 +21: movnti %r8,(%rdi) + leaq 8(%rsi),%rsi + leaq 8(%rdi),%rdi + decl %ecx + jnz .L_8b_nocache_copy_loop + + /* If no byte left, we're done */ +.L_4b_nocache_copy_entry: + andl %edx,%edx + jz .L_finish_copy + + /* If destination is not 4-byte aligned, go to byte copy: */ + movl %edi,%ecx + andl $3,%ecx + jnz .L_1b_cache_copy_entry + + /* Set 4-byte copy count (1 or 0) and remainder */ + movl %edx,%ecx + andl $3,%edx + shrl $2,%ecx + jz .L_1b_cache_copy_entry /* jump if count is 0 */ + + /* Perform 4-byte nocache copy: */ +30: movl (%rsi),%r8d +31: movnti %r8d,(%rdi) + leaq 4(%rsi),%rsi + leaq 4(%rdi),%rdi + + /* If no bytes left, we're done: */ + andl %edx,%edx + jz .L_finish_copy + + /* Perform byte "cache" loop-copy for the remainder */ +.L_1b_cache_copy_entry: + movl %edx,%ecx +.L_1b_cache_copy_loop: +40: movb (%rsi),%al +41: movb %al,(%rdi) + incq %rsi + incq %rdi + decl %ecx + jnz .L_1b_cache_copy_loop + + /* Finished copying; fence the prior stores */ +.L_finish_copy: + xorl %eax,%eax + ASM_CLAC + sfence + RET + +.L_fixup_4x8b_copy: + shll $6,%ecx + addl %ecx,%edx + jmp .L_fixup_handle_tail +.L_fixup_8b_copy: + lea (%rdx,%rcx,8),%rdx + jmp .L_fixup_handle_tail +.L_fixup_4b_copy: + lea (%rdx,%rcx,4),%rdx + jmp .L_fixup_handle_tail +.L_fixup_1b_copy: + movl %ecx,%edx +.L_fixup_handle_tail: + sfence + jmp .Lcopy_user_handle_tail + + _ASM_EXTABLE_CPY(1b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(2b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(3b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(4b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(5b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(6b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(7b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(8b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(9b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(10b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(11b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(12b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(13b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(14b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(15b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(16b, .L_fixup_4x8b_copy) + _ASM_EXTABLE_CPY(20b, .L_fixup_8b_copy) + _ASM_EXTABLE_CPY(21b, .L_fixup_8b_copy) + _ASM_EXTABLE_CPY(30b, .L_fixup_4b_copy) + _ASM_EXTABLE_CPY(31b, .L_fixup_4b_copy) + _ASM_EXTABLE_CPY(40b, .L_fixup_1b_copy) + _ASM_EXTABLE_CPY(41b, .L_fixup_1b_copy) +SYM_FUNC_END(__copy_user_nocache) +EXPORT_SYMBOL(__copy_user_nocache) |