Messages in this thread Patch in this message | | | Date | Wed, 10 Nov 2021 11:01:04 +0100 | From | Peter Zijlstra <> | Subject | [PATCH v2 02/23] x86,mmx_32: Remove .fixup usage |
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This code puts an exception table entry on the PREFETCH instruction to overwrite it with a JMP.d8 when it triggers an exception. Except of course, our code is no longer writable, also SMP.
Replace it with ALTERNATIVE, the 'new' way of doing these things.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/lib/mmx_32.c | 86 +++++++++++++++++--------------------------------- 1 file changed, 30 insertions(+), 56 deletions(-)
--- a/arch/x86/lib/mmx_32.c +++ b/arch/x86/lib/mmx_32.c @@ -50,23 +50,18 @@ void *_mmx_memcpy(void *to, const void * kernel_fpu_begin_mask(KFPU_387); __asm__ __volatile__ ( - "1: prefetch (%0)\n" /* This set is 28 bytes */ - " prefetch 64(%0)\n" - " prefetch 128(%0)\n" - " prefetch 192(%0)\n" - " prefetch 256(%0)\n" - "2: \n" - ".section .fixup, \"ax\"\n" - "3: movw $0x1AEB, 1b\n" /* jmp on 26 bytes */ - " jmp 2b\n" - ".previous\n" - _ASM_EXTABLE(1b, 3b) - : : "r" (from)); + ALTERNATIVE "", + "prefetch (%0)\n" + "prefetch 64(%0)\n" + "prefetch 128(%0)\n" + "prefetch 192(%0)\n" + "prefetch 256(%0)\n", X86_FEATURE_3DNOWPREFETCH + : : "r" (from)); for ( ; i > 5; i--) { __asm__ __volatile__ ( - "1: prefetch 320(%0)\n" - "2: movq (%0), %%mm0\n" + ALTERNATIVE "", "prefetch 320(%0)\n", X86_FEATURE_3DNOWPREFETCH + " movq (%0), %%mm0\n" " movq 8(%0), %%mm1\n" " movq 16(%0), %%mm2\n" " movq 24(%0), %%mm3\n" @@ -82,11 +77,6 @@ void *_mmx_memcpy(void *to, const void * " movq %%mm1, 40(%1)\n" " movq %%mm2, 48(%1)\n" " movq %%mm3, 56(%1)\n" - ".section .fixup, \"ax\"\n" - "3: movw $0x05EB, 1b\n" /* jmp on 5 bytes */ - " jmp 2b\n" - ".previous\n" - _ASM_EXTABLE(1b, 3b) : : "r" (from), "r" (to) : "memory"); from += 64; @@ -177,22 +167,18 @@ static void fast_copy_page(void *to, voi * but that is for later. -AV */ __asm__ __volatile__( - "1: prefetch (%0)\n" - " prefetch 64(%0)\n" - " prefetch 128(%0)\n" - " prefetch 192(%0)\n" - " prefetch 256(%0)\n" - "2: \n" - ".section .fixup, \"ax\"\n" - "3: movw $0x1AEB, 1b\n" /* jmp on 26 bytes */ - " jmp 2b\n" - ".previous\n" - _ASM_EXTABLE(1b, 3b) : : "r" (from)); + ALTERNATIVE "", + "prefetch (%0)\n" + "prefetch 64(%0)\n" + "prefetch 128(%0)\n" + "prefetch 192(%0)\n" + "prefetch 256(%0)\n", X86_FEATURE_3DNOWPREFETCH + : : "r" (from)); for (i = 0; i < (4096-320)/64; i++) { __asm__ __volatile__ ( - "1: prefetch 320(%0)\n" - "2: movq (%0), %%mm0\n" + ALTERNATIVE "", "prefetch 320(%0)\n", X86_FEATURE_3DNOWPREFETCH + " movq (%0), %%mm0\n" " movntq %%mm0, (%1)\n" " movq 8(%0), %%mm1\n" " movntq %%mm1, 8(%1)\n" @@ -208,11 +194,7 @@ static void fast_copy_page(void *to, voi " movntq %%mm6, 48(%1)\n" " movq 56(%0), %%mm7\n" " movntq %%mm7, 56(%1)\n" - ".section .fixup, \"ax\"\n" - "3: movw $0x05EB, 1b\n" /* jmp on 5 bytes */ - " jmp 2b\n" - ".previous\n" - _ASM_EXTABLE(1b, 3b) : : "r" (from), "r" (to) : "memory"); + : : "r" (from), "r" (to) : "memory"); from += 64; to += 64; @@ -220,7 +202,7 @@ static void fast_copy_page(void *to, voi for (i = (4096-320)/64; i < 4096/64; i++) { __asm__ __volatile__ ( - "2: movq (%0), %%mm0\n" + " movq (%0), %%mm0\n" " movntq %%mm0, (%1)\n" " movq 8(%0), %%mm1\n" " movntq %%mm1, 8(%1)\n" @@ -237,6 +219,7 @@ static void fast_copy_page(void *to, voi " movq 56(%0), %%mm7\n" " movntq %%mm7, 56(%1)\n" : : "r" (from), "r" (to) : "memory"); + from += 64; to += 64; } @@ -295,22 +278,18 @@ static void fast_copy_page(void *to, voi kernel_fpu_begin_mask(KFPU_387); __asm__ __volatile__ ( - "1: prefetch (%0)\n" - " prefetch 64(%0)\n" - " prefetch 128(%0)\n" - " prefetch 192(%0)\n" - " prefetch 256(%0)\n" - "2: \n" - ".section .fixup, \"ax\"\n" - "3: movw $0x1AEB, 1b\n" /* jmp on 26 bytes */ - " jmp 2b\n" - ".previous\n" - _ASM_EXTABLE(1b, 3b) : : "r" (from)); + ALTERNATIVE "", + "prefetch (%0)\n" + "prefetch 64(%0)\n" + "prefetch 128(%0)\n" + "prefetch 192(%0)\n" + "prefetch 256(%0)\n", X86_FEATURE_3DNOWPREFETCH + : : "r" (from)); for (i = 0; i < 4096/64; i++) { __asm__ __volatile__ ( - "1: prefetch 320(%0)\n" - "2: movq (%0), %%mm0\n" + ALTERNATIVE "", "prefetch 320(%0)\n", X86_FEATURE_3DNOWPREFETCH + " movq (%0), %%mm0\n" " movq 8(%0), %%mm1\n" " movq 16(%0), %%mm2\n" " movq 24(%0), %%mm3\n" @@ -326,11 +305,6 @@ static void fast_copy_page(void *to, voi " movq %%mm1, 40(%1)\n" " movq %%mm2, 48(%1)\n" " movq %%mm3, 56(%1)\n" - ".section .fixup, \"ax\"\n" - "3: movw $0x05EB, 1b\n" /* jmp on 5 bytes */ - " jmp 2b\n" - ".previous\n" - _ASM_EXTABLE(1b, 3b) : : "r" (from), "r" (to) : "memory"); from += 64;
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