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Merge tag 'x86_asm_for_v6.2' of git://git.kernel.org/pub/scm/linux/ke…
…rnel/git/tip/tip Pull x86 asm updates from Borislav Petkov: - Move the 32-bit memmove() asm implementation out-of-line in order to fix a 32-bit full LTO build failure with clang where it would fail at register allocation. Move it to an asm file and clean it up while at it, similar to what has been already done on 64-bit * tag 'x86_asm_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mem: Move memmove to out of line assembler
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,200 @@ | ||
| /* SPDX-License-Identifier: GPL-2.0 */ | ||
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| #include <linux/linkage.h> | ||
| #include <asm/export.h> | ||
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| SYM_FUNC_START(memmove) | ||
| /* | ||
| * void *memmove(void *dest_in, const void *src_in, size_t n) | ||
| * -mregparm=3 passes these in registers: | ||
| * dest_in: %eax | ||
| * src_in: %edx | ||
| * n: %ecx | ||
| * See also: arch/x86/entry/calling.h for description of the calling convention. | ||
| * | ||
| * n can remain in %ecx, but for `rep movsl`, we'll need dest in %edi and src | ||
| * in %esi. | ||
| */ | ||
| .set dest_in, %eax | ||
| .set dest, %edi | ||
| .set src_in, %edx | ||
| .set src, %esi | ||
| .set n, %ecx | ||
| .set tmp0, %edx | ||
| .set tmp0w, %dx | ||
| .set tmp1, %ebx | ||
| .set tmp1w, %bx | ||
| .set tmp2, %eax | ||
| .set tmp3b, %cl | ||
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| /* | ||
| * Save all callee-saved registers, because this function is going to clobber | ||
| * all of them: | ||
| */ | ||
| pushl %ebp | ||
| movl %esp, %ebp // set standard frame pointer | ||
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| pushl %ebx | ||
| pushl %edi | ||
| pushl %esi | ||
| pushl %eax // save 'dest_in' parameter [eax] as the return value | ||
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| movl src_in, src | ||
| movl dest_in, dest | ||
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| /* Handle more 16 bytes in loop */ | ||
| cmpl $0x10, n | ||
| jb .Lmove_16B | ||
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| /* Decide forward/backward copy mode */ | ||
| cmpl dest, src | ||
| jb .Lbackwards_header | ||
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| /* | ||
| * movs instruction have many startup latency | ||
| * so we handle small size by general register. | ||
| */ | ||
| cmpl $680, n | ||
| jb .Ltoo_small_forwards | ||
| /* movs instruction is only good for aligned case. */ | ||
| movl src, tmp0 | ||
| xorl dest, tmp0 | ||
| andl $0xff, tmp0 | ||
| jz .Lforward_movs | ||
| .Ltoo_small_forwards: | ||
| subl $0x10, n | ||
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| /* We gobble 16 bytes forward in each loop. */ | ||
| .Lmove_16B_forwards_loop: | ||
| subl $0x10, n | ||
| movl 0*4(src), tmp0 | ||
| movl 1*4(src), tmp1 | ||
| movl tmp0, 0*4(dest) | ||
| movl tmp1, 1*4(dest) | ||
| movl 2*4(src), tmp0 | ||
| movl 3*4(src), tmp1 | ||
| movl tmp0, 2*4(dest) | ||
| movl tmp1, 3*4(dest) | ||
| leal 0x10(src), src | ||
| leal 0x10(dest), dest | ||
| jae .Lmove_16B_forwards_loop | ||
| addl $0x10, n | ||
| jmp .Lmove_16B | ||
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| /* Handle data forward by movs. */ | ||
| .p2align 4 | ||
| .Lforward_movs: | ||
| movl -4(src, n), tmp0 | ||
| leal -4(dest, n), tmp1 | ||
| shrl $2, n | ||
| rep movsl | ||
| movl tmp0, (tmp1) | ||
| jmp .Ldone | ||
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| /* Handle data backward by movs. */ | ||
| .p2align 4 | ||
| .Lbackwards_movs: | ||
| movl (src), tmp0 | ||
| movl dest, tmp1 | ||
| leal -4(src, n), src | ||
| leal -4(dest, n), dest | ||
| shrl $2, n | ||
| std | ||
| rep movsl | ||
| movl tmp0,(tmp1) | ||
| cld | ||
| jmp .Ldone | ||
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| /* Start to prepare for backward copy. */ | ||
| .p2align 4 | ||
| .Lbackwards_header: | ||
| cmpl $680, n | ||
| jb .Ltoo_small_backwards | ||
| movl src, tmp0 | ||
| xorl dest, tmp0 | ||
| andl $0xff, tmp0 | ||
| jz .Lbackwards_movs | ||
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| /* Calculate copy position to tail. */ | ||
| .Ltoo_small_backwards: | ||
| addl n, src | ||
| addl n, dest | ||
| subl $0x10, n | ||
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| /* We gobble 16 bytes backward in each loop. */ | ||
| .Lmove_16B_backwards_loop: | ||
| subl $0x10, n | ||
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| movl -1*4(src), tmp0 | ||
| movl -2*4(src), tmp1 | ||
| movl tmp0, -1*4(dest) | ||
| movl tmp1, -2*4(dest) | ||
| movl -3*4(src), tmp0 | ||
| movl -4*4(src), tmp1 | ||
| movl tmp0, -3*4(dest) | ||
| movl tmp1, -4*4(dest) | ||
| leal -0x10(src), src | ||
| leal -0x10(dest), dest | ||
| jae .Lmove_16B_backwards_loop | ||
| /* Calculate copy position to head. */ | ||
| addl $0x10, n | ||
| subl n, src | ||
| subl n, dest | ||
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| /* Move data from 8 bytes to 15 bytes. */ | ||
| .p2align 4 | ||
| .Lmove_16B: | ||
| cmpl $8, n | ||
| jb .Lmove_8B | ||
| movl 0*4(src), tmp0 | ||
| movl 1*4(src), tmp1 | ||
| movl -2*4(src, n), tmp2 | ||
| movl -1*4(src, n), src | ||
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| movl tmp0, 0*4(dest) | ||
| movl tmp1, 1*4(dest) | ||
| movl tmp2, -2*4(dest, n) | ||
| movl src, -1*4(dest, n) | ||
| jmp .Ldone | ||
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| /* Move data from 4 bytes to 7 bytes. */ | ||
| .p2align 4 | ||
| .Lmove_8B: | ||
| cmpl $4, n | ||
| jb .Lmove_4B | ||
| movl 0*4(src), tmp0 | ||
| movl -1*4(src, n), tmp1 | ||
| movl tmp0, 0*4(dest) | ||
| movl tmp1, -1*4(dest, n) | ||
| jmp .Ldone | ||
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| /* Move data from 2 bytes to 3 bytes. */ | ||
| .p2align 4 | ||
| .Lmove_4B: | ||
| cmpl $2, n | ||
| jb .Lmove_1B | ||
| movw 0*2(src), tmp0w | ||
| movw -1*2(src, n), tmp1w | ||
| movw tmp0w, 0*2(dest) | ||
| movw tmp1w, -1*2(dest, n) | ||
| jmp .Ldone | ||
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| /* Move data for 1 byte. */ | ||
| .p2align 4 | ||
| .Lmove_1B: | ||
| cmpl $1, n | ||
| jb .Ldone | ||
| movb (src), tmp3b | ||
| movb tmp3b, (dest) | ||
| .p2align 4 | ||
| .Ldone: | ||
| popl dest_in // restore 'dest_in' [eax] as the return value | ||
| /* Restore all callee-saved registers: */ | ||
| popl %esi | ||
| popl %edi | ||
| popl %ebx | ||
| popl %ebp | ||
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| RET | ||
| SYM_FUNC_END(memmove) | ||
| EXPORT_SYMBOL(memmove) |
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