| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* Copyright 2002 Andi Kleen */ |
| |
| #include <linux/linkage.h> |
| #include <asm/errno.h> |
| #include <asm/cpufeatures.h> |
| #include <asm/mcsafe_test.h> |
| #include <asm/alternative-asm.h> |
| #include <asm/export.h> |
| |
| /* |
| * We build a jump to memcpy_orig by default which gets NOPped out on |
| * the majority of x86 CPUs which set REP_GOOD. In addition, CPUs which |
| * have the enhanced REP MOVSB/STOSB feature (ERMS), change those NOPs |
| * to a jmp to memcpy_erms which does the REP; MOVSB mem copy. |
| */ |
| |
| .weak memcpy |
| |
| /* |
| * memcpy - Copy a memory block. |
| * |
| * Input: |
| * rdi destination |
| * rsi source |
| * rdx count |
| * |
| * Output: |
| * rax original destination |
| */ |
| SYM_FUNC_START_ALIAS(__memcpy) |
| SYM_FUNC_START_LOCAL(memcpy) |
| ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \ |
| "jmp memcpy_erms", X86_FEATURE_ERMS |
| |
| movq %rdi, %rax |
| movq %rdx, %rcx |
| shrq $3, %rcx |
| andl $7, %edx |
| rep movsq |
| movl %edx, %ecx |
| rep movsb |
| ret |
| SYM_FUNC_END(memcpy) |
| SYM_FUNC_END_ALIAS(__memcpy) |
| EXPORT_SYMBOL(memcpy) |
| EXPORT_SYMBOL(__memcpy) |
| |
| /* |
| * memcpy_erms() - enhanced fast string memcpy. This is faster and |
| * simpler than memcpy. Use memcpy_erms when possible. |
| */ |
| SYM_FUNC_START_LOCAL(memcpy_erms) |
| movq %rdi, %rax |
| movq %rdx, %rcx |
| rep movsb |
| ret |
| SYM_FUNC_END(memcpy_erms) |
| |
| SYM_FUNC_START_LOCAL(memcpy_orig) |
| movq %rdi, %rax |
| |
| cmpq $0x20, %rdx |
| jb .Lhandle_tail |
| |
| /* |
| * We check whether memory false dependence could occur, |
| * then jump to corresponding copy mode. |
| */ |
| cmp %dil, %sil |
| jl .Lcopy_backward |
| subq $0x20, %rdx |
| .Lcopy_forward_loop: |
| subq $0x20, %rdx |
| |
| /* |
| * Move in blocks of 4x8 bytes: |
| */ |
| movq 0*8(%rsi), %r8 |
| movq 1*8(%rsi), %r9 |
| movq 2*8(%rsi), %r10 |
| movq 3*8(%rsi), %r11 |
| leaq 4*8(%rsi), %rsi |
| |
| movq %r8, 0*8(%rdi) |
| movq %r9, 1*8(%rdi) |
| movq %r10, 2*8(%rdi) |
| movq %r11, 3*8(%rdi) |
| leaq 4*8(%rdi), %rdi |
| jae .Lcopy_forward_loop |
| addl $0x20, %edx |
| jmp .Lhandle_tail |
| |
| .Lcopy_backward: |
| /* |
| * Calculate copy position to tail. |
| */ |
| addq %rdx, %rsi |
| addq %rdx, %rdi |
| subq $0x20, %rdx |
| /* |
| * At most 3 ALU operations in one cycle, |
| * so append NOPS in the same 16 bytes trunk. |
| */ |
| .p2align 4 |
| .Lcopy_backward_loop: |
| subq $0x20, %rdx |
| movq -1*8(%rsi), %r8 |
| movq -2*8(%rsi), %r9 |
| movq -3*8(%rsi), %r10 |
| movq -4*8(%rsi), %r11 |
| leaq -4*8(%rsi), %rsi |
| movq %r8, -1*8(%rdi) |
| movq %r9, -2*8(%rdi) |
| movq %r10, -3*8(%rdi) |
| movq %r11, -4*8(%rdi) |
| leaq -4*8(%rdi), %rdi |
| jae .Lcopy_backward_loop |
| |
| /* |
| * Calculate copy position to head. |
| */ |
| addl $0x20, %edx |
| subq %rdx, %rsi |
| subq %rdx, %rdi |
| .Lhandle_tail: |
| cmpl $16, %edx |
| jb .Lless_16bytes |
| |
| /* |
| * Move data from 16 bytes to 31 bytes. |
| */ |
| movq 0*8(%rsi), %r8 |
| movq 1*8(%rsi), %r9 |
| movq -2*8(%rsi, %rdx), %r10 |
| movq -1*8(%rsi, %rdx), %r11 |
| movq %r8, 0*8(%rdi) |
| movq %r9, 1*8(%rdi) |
| movq %r10, -2*8(%rdi, %rdx) |
| movq %r11, -1*8(%rdi, %rdx) |
| retq |
| .p2align 4 |
| .Lless_16bytes: |
| cmpl $8, %edx |
| jb .Lless_8bytes |
| /* |
| * Move data from 8 bytes to 15 bytes. |
| */ |
| movq 0*8(%rsi), %r8 |
| movq -1*8(%rsi, %rdx), %r9 |
| movq %r8, 0*8(%rdi) |
| movq %r9, -1*8(%rdi, %rdx) |
| retq |
| .p2align 4 |
| .Lless_8bytes: |
| cmpl $4, %edx |
| jb .Lless_3bytes |
| |
| /* |
| * Move data from 4 bytes to 7 bytes. |
| */ |
| movl (%rsi), %ecx |
| movl -4(%rsi, %rdx), %r8d |
| movl %ecx, (%rdi) |
| movl %r8d, -4(%rdi, %rdx) |
| retq |
| .p2align 4 |
| .Lless_3bytes: |
| subl $1, %edx |
| jb .Lend |
| /* |
| * Move data from 1 bytes to 3 bytes. |
| */ |
| movzbl (%rsi), %ecx |
| jz .Lstore_1byte |
| movzbq 1(%rsi), %r8 |
| movzbq (%rsi, %rdx), %r9 |
| movb %r8b, 1(%rdi) |
| movb %r9b, (%rdi, %rdx) |
| .Lstore_1byte: |
| movb %cl, (%rdi) |
| |
| .Lend: |
| retq |
| SYM_FUNC_END(memcpy_orig) |
| |
| #ifndef CONFIG_UML |
| |
| MCSAFE_TEST_CTL |
| |
| /* |
| * __memcpy_mcsafe - memory copy with machine check exception handling |
| * Note that we only catch machine checks when reading the source addresses. |
| * Writes to target are posted and don't generate machine checks. |
| */ |
| SYM_FUNC_START(__memcpy_mcsafe) |
| cmpl $8, %edx |
| /* Less than 8 bytes? Go to byte copy loop */ |
| jb .L_no_whole_words |
| |
| /* Check for bad alignment of source */ |
| testl $7, %esi |
| /* Already aligned */ |
| jz .L_8byte_aligned |
| |
| /* Copy one byte at a time until source is 8-byte aligned */ |
| movl %esi, %ecx |
| andl $7, %ecx |
| subl $8, %ecx |
| negl %ecx |
| subl %ecx, %edx |
| .L_read_leading_bytes: |
| movb (%rsi), %al |
| MCSAFE_TEST_SRC %rsi 1 .E_leading_bytes |
| MCSAFE_TEST_DST %rdi 1 .E_leading_bytes |
| .L_write_leading_bytes: |
| movb %al, (%rdi) |
| incq %rsi |
| incq %rdi |
| decl %ecx |
| jnz .L_read_leading_bytes |
| |
| .L_8byte_aligned: |
| movl %edx, %ecx |
| andl $7, %edx |
| shrl $3, %ecx |
| jz .L_no_whole_words |
| |
| .L_read_words: |
| movq (%rsi), %r8 |
| MCSAFE_TEST_SRC %rsi 8 .E_read_words |
| MCSAFE_TEST_DST %rdi 8 .E_write_words |
| .L_write_words: |
| movq %r8, (%rdi) |
| addq $8, %rsi |
| addq $8, %rdi |
| decl %ecx |
| jnz .L_read_words |
| |
| /* Any trailing bytes? */ |
| .L_no_whole_words: |
| andl %edx, %edx |
| jz .L_done_memcpy_trap |
| |
| /* Copy trailing bytes */ |
| movl %edx, %ecx |
| .L_read_trailing_bytes: |
| movb (%rsi), %al |
| MCSAFE_TEST_SRC %rsi 1 .E_trailing_bytes |
| MCSAFE_TEST_DST %rdi 1 .E_trailing_bytes |
| .L_write_trailing_bytes: |
| movb %al, (%rdi) |
| incq %rsi |
| incq %rdi |
| decl %ecx |
| jnz .L_read_trailing_bytes |
| |
| /* Copy successful. Return zero */ |
| .L_done_memcpy_trap: |
| xorl %eax, %eax |
| .L_done: |
| ret |
| SYM_FUNC_END(__memcpy_mcsafe) |
| EXPORT_SYMBOL_GPL(__memcpy_mcsafe) |
| |
| .section .fixup, "ax" |
| /* |
| * Return number of bytes not copied for any failure. Note that |
| * there is no "tail" handling since the source buffer is 8-byte |
| * aligned and poison is cacheline aligned. |
| */ |
| .E_read_words: |
| shll $3, %ecx |
| .E_leading_bytes: |
| addl %edx, %ecx |
| .E_trailing_bytes: |
| mov %ecx, %eax |
| jmp .L_done |
| |
| /* |
| * For write fault handling, given the destination is unaligned, |
| * we handle faults on multi-byte writes with a byte-by-byte |
| * copy up to the write-protected page. |
| */ |
| .E_write_words: |
| shll $3, %ecx |
| addl %edx, %ecx |
| movl %ecx, %edx |
| jmp mcsafe_handle_tail |
| |
| .previous |
| |
| _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .E_leading_bytes) |
| _ASM_EXTABLE_FAULT(.L_read_words, .E_read_words) |
| _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .E_trailing_bytes) |
| _ASM_EXTABLE(.L_write_leading_bytes, .E_leading_bytes) |
| _ASM_EXTABLE(.L_write_words, .E_write_words) |
| _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes) |
| #endif |
