From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
jpoimboe@redhat.com, mark.rutland@arm.com, dvyukov@google.com,
seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz
Subject: [PATCH 02/22] x86,mmx_32: Remove .fixup usage
Date: Fri, 05 Nov 2021 18:10:25 +0100 [thread overview]
Message-ID: <20211105171820.568721583@infradead.org> (raw)
In-Reply-To: 20211105171023.989862879@infradead.org
This code puts an exception table entry on the "PREFIX" 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 novel
XXX: arguably we should just delete this code
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;
next prev parent reply other threads:[~2021-11-05 17:20 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-05 17:10 [PATCH 00/22] x86: Remove anonymous out-of-line fixups Peter Zijlstra
2021-11-05 17:10 ` [PATCH 01/22] bitfield.h: Fix "type of reg too small for mask" test Peter Zijlstra
2021-11-05 17:10 ` Peter Zijlstra [this message]
2021-11-05 17:10 ` [PATCH 03/22] x86,copy_user_64: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 04/22] x86,copy_mc_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 05/22] x86,entry_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 06/22] x86,entry_32: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 07/22] x86,extable: Extend extable functionality Peter Zijlstra
2021-11-05 17:10 ` [PATCH 08/22] x86,msr: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 09/22] x86,futex: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 10/22] x86,uaccess: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 11/22] x86,xen: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 12/22] x86,fpu: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 13/22] x86,segment: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 14/22] x86,vmx: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 15/22] x86,checksum_32: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 16/22] x86,sgx: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 17/22] x86,kvm: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 18/22] x86,usercopy_32: Simplify __copy_user_intel_nocache() Peter Zijlstra
2021-11-05 17:10 ` [PATCH 19/22] x86,usercopy: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 20/22] x86,word-at-a-time: " Peter Zijlstra
2021-11-05 18:01 ` Josh Poimboeuf
2021-11-05 18:07 ` Peter Zijlstra
2021-11-08 16:47 ` Josh Poimboeuf
2021-11-08 18:29 ` Peter Zijlstra
2021-11-08 18:53 ` Nick Desaulniers
2021-11-09 8:23 ` Peter Zijlstra
2021-11-09 19:22 ` Nick Desaulniers
2021-11-09 20:59 ` Bill Wendling
2021-11-09 21:21 ` Peter Zijlstra
2021-11-09 21:25 ` Nick Desaulniers
2021-11-09 22:11 ` Peter Zijlstra
2021-11-09 22:15 ` Nick Desaulniers
2021-11-09 21:07 ` Peter Zijlstra
2021-11-10 10:18 ` Peter Zijlstra
2021-11-10 10:46 ` David Laight
2021-11-10 11:09 ` Peter Zijlstra
2021-11-10 12:20 ` David Laight
2021-11-12 1:50 ` Josh Poimboeuf
2021-11-12 9:33 ` Peter Zijlstra
2021-11-13 5:35 ` Josh Poimboeuf
2021-11-15 12:36 ` Miroslav Benes
2021-11-15 13:01 ` Joe Lawrence
2021-11-15 23:40 ` Josh Poimboeuf
2021-11-16 7:25 ` Miroslav Benes
2021-11-15 12:59 ` Miroslav Benes
2021-11-16 21:27 ` Josh Poimboeuf
2021-11-18 7:15 ` Miroslav Benes
2021-11-22 17:46 ` Petr Mladek
2021-11-24 17:42 ` Josh Poimboeuf
2021-11-25 8:18 ` Petr Mladek
2021-11-10 12:14 ` Segher Boessenkool
2021-11-05 17:10 ` [PATCH 21/22] x86: Remove .fixup section Peter Zijlstra
2021-11-05 17:10 ` [PATCH 22/22] objtool: Remove .fixup handling Peter Zijlstra
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