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x86/mmx_32: Remove X86_USE_3DNOW 

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.

Instead of fixing this broken mess, simply take it out.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/YZKQzUmeNuwyvZpk@hirez.programming.kicks-ass.net
This commit is contained in:
Peter Zijlstra 2021-11-15 17:46:39 +01:00
parent bff8c3848e
commit c6dbd3e5e6
11 changed files with 1 additions and 469 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/Kconfig
View File

@ -1957,7 +1957,7 @@ config EFI
config EFI_STUB
bool "EFI stub support"
depends on EFI && !X86_USE_3DNOW
depends on EFI
depends on $(cc-option,-mabi=ms) || X86_32
select RELOCATABLE
help

4
arch/x86/Kconfig.cpu
View File

@ -342,10 +342,6 @@ config X86_USE_PPRO_CHECKSUM
def_bool y
depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MK7 || MK6 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC3_2 || MVIAC7 || MEFFICEON || MGEODE_LX || MCORE2 || MATOM
config X86_USE_3DNOW
def_bool y
depends on (MCYRIXIII || MK7 || MGEODE_LX) && !UML
#
# P6_NOPs are a relatively minor optimization that require a family >=
# 6 processor, except that it is broken on certain VIA chips.

15
arch/x86/include/asm/mmx.h
View File

@ -1,15 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_MMX_H
#define _ASM_X86_MMX_H
/*
* MMX 3Dnow! helper operations
*/
#include <linux/types.h>
extern void *_mmx_memcpy(void *to, const void *from, size_t size);
extern void mmx_clear_page(void *page);
extern void mmx_copy_page(void *to, void *from);
#endif /* _ASM_X86_MMX_H */

14
arch/x86/include/asm/page_32.h
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@ -19,19 +19,6 @@ extern unsigned long __phys_addr(unsigned long);
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#endif /* CONFIG_FLATMEM */
#ifdef CONFIG_X86_USE_3DNOW
#include <asm/mmx.h>
static inline void clear_page(void *page)
{
mmx_clear_page(page);
}
static inline void copy_page(void *to, void *from)
{
mmx_copy_page(to, from);
}
#else /* !CONFIG_X86_USE_3DNOW */
#include <linux/string.h>
static inline void clear_page(void *page)
@ -43,7 +30,6 @@ static inline void copy_page(void *to, void *from)
{
memcpy(to, from, PAGE_SIZE);
}
#endif /* CONFIG_X86_USE_3DNOW */
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_X86_PAGE_32_H */

4
arch/x86/include/asm/required-features.h
View File

@ -35,11 +35,7 @@
# define NEED_CMOV 0
#endif
#ifdef CONFIG_X86_USE_3DNOW
# define NEED_3DNOW (1<<(X86_FEATURE_3DNOW & 31))
#else
# define NEED_3DNOW 0
#endif
#if defined(CONFIG_X86_P6_NOP) || defined(CONFIG_X86_64)
# define NEED_NOPL (1<<(X86_FEATURE_NOPL & 31))

33
arch/x86/include/asm/string_32.h
View File

@ -146,42 +146,9 @@ static __always_inline void *__constant_memcpy(void *to, const void *from,
extern void *memcpy(void *, const void *, size_t);
#ifndef CONFIG_FORTIFY_SOURCE
#ifdef CONFIG_X86_USE_3DNOW
#include <asm/mmx.h>
/*
* This CPU favours 3DNow strongly (eg AMD Athlon)
*/
static inline void *__constant_memcpy3d(void *to, const void *from, size_t len)
{
if (len < 512)
return __constant_memcpy(to, from, len);
return _mmx_memcpy(to, from, len);
}
static inline void *__memcpy3d(void *to, const void *from, size_t len)
{
if (len < 512)
return __memcpy(to, from, len);
return _mmx_memcpy(to, from, len);
}
#define memcpy(t, f, n) \
(__builtin_constant_p((n)) \
? __constant_memcpy3d((t), (f), (n)) \
: __memcpy3d((t), (f), (n)))
#else
/*
* No 3D Now!
*/
#define memcpy(t, f, n) __builtin_memcpy(t, f, n)
#endif
#endif /* !CONFIG_FORTIFY_SOURCE */
#define __HAVE_ARCH_MEMMOVE

1
arch/x86/lib/Makefile
View File

@ -63,7 +63,6 @@ ifeq ($(CONFIG_X86_32),y)
ifneq ($(CONFIG_X86_CMPXCHG64),y)
lib-y += cmpxchg8b_emu.o atomic64_386_32.o
endif
lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o
else
obj-y += iomap_copy_64.o
lib-y += csum-partial_64.o csum-copy_64.o csum-wrappers_64.o

4
arch/x86/lib/memcpy_32.c
View File

@ -7,11 +7,7 @@
__visible void *memcpy(void *to, const void *from, size_t n)
{
#if defined(CONFIG_X86_USE_3DNOW) && !defined(CONFIG_FORTIFY_SOURCE)
return __memcpy3d(to, from, n);
#else
return __memcpy(to, from, n);
#endif
}
EXPORT_SYMBOL(memcpy);

388
arch/x86/lib/mmx_32.c
View File

@ -1,388 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
/*
* MMX 3DNow! library helper functions
*
* To do:
* We can use MMX just for prefetch in IRQ's. This may be a win.
* (reported so on K6-III)
* We should use a better code neutral filler for the short jump
* leal ebx. [ebx] is apparently best for K6-2, but Cyrix ??
* We also want to clobber the filler register so we don't get any
* register forwarding stalls on the filler.
*
* Add *user handling. Checksums are not a win with MMX on any CPU
* tested so far for any MMX solution figured.
*
* 22/09/2000 - Arjan van de Ven
* Improved for non-engineering-sample Athlons
*
*/
#include <linux/hardirq.h>
#include <linux/string.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <asm/fpu/api.h>
#include <asm/asm.h>
/*
* Use KFPU_387. MMX instructions are not affected by MXCSR,
* but both AMD and Intel documentation states that even integer MMX
* operations will result in #MF if an exception is pending in FCW.
*
* EMMS is not needed afterwards because, after calling kernel_fpu_end(),
* any subsequent user of the 387 stack will reinitialize it using
* KFPU_387.
*/
void *_mmx_memcpy(void *to, const void *from, size_t len)
{
void *p;
int i;
if (unlikely(in_interrupt()))
return __memcpy(to, from, len);
p = to;
i = len >> 6; /* len/64 */
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));
for ( ; i > 5; i--) {
__asm__ __volatile__ (
"1: prefetch 320(%0)\n"
"2: movq (%0), %%mm0\n"
" movq 8(%0), %%mm1\n"
" movq 16(%0), %%mm2\n"
" movq 24(%0), %%mm3\n"
" movq %%mm0, (%1)\n"
" movq %%mm1, 8(%1)\n"
" movq %%mm2, 16(%1)\n"
" movq %%mm3, 24(%1)\n"
" movq 32(%0), %%mm0\n"
" movq 40(%0), %%mm1\n"
" movq 48(%0), %%mm2\n"
" movq 56(%0), %%mm3\n"
" movq %%mm0, 32(%1)\n"
" 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;
to += 64;
}
for ( ; i > 0; i--) {
__asm__ __volatile__ (
" movq (%0), %%mm0\n"
" movq 8(%0), %%mm1\n"
" movq 16(%0), %%mm2\n"
" movq 24(%0), %%mm3\n"
" movq %%mm0, (%1)\n"
" movq %%mm1, 8(%1)\n"
" movq %%mm2, 16(%1)\n"
" movq %%mm3, 24(%1)\n"
" movq 32(%0), %%mm0\n"
" movq 40(%0), %%mm1\n"
" movq 48(%0), %%mm2\n"
" movq 56(%0), %%mm3\n"
" movq %%mm0, 32(%1)\n"
" movq %%mm1, 40(%1)\n"
" movq %%mm2, 48(%1)\n"
" movq %%mm3, 56(%1)\n"
: : "r" (from), "r" (to) : "memory");
from += 64;
to += 64;
}
/*
* Now do the tail of the block:
*/
__memcpy(to, from, len & 63);
kernel_fpu_end();
return p;
}
EXPORT_SYMBOL(_mmx_memcpy);
#ifdef CONFIG_MK7
/*
* The K7 has streaming cache bypass load/store. The Cyrix III, K6 and
* other MMX using processors do not.
*/
static void fast_clear_page(void *page)
{
int i;
kernel_fpu_begin_mask(KFPU_387);
__asm__ __volatile__ (
" pxor %%mm0, %%mm0\n" : :
);
for (i = 0; i < 4096/64; i++) {
__asm__ __volatile__ (
" movntq %%mm0, (%0)\n"
" movntq %%mm0, 8(%0)\n"
" movntq %%mm0, 16(%0)\n"
" movntq %%mm0, 24(%0)\n"
" movntq %%mm0, 32(%0)\n"
" movntq %%mm0, 40(%0)\n"
" movntq %%mm0, 48(%0)\n"
" movntq %%mm0, 56(%0)\n"
: : "r" (page) : "memory");
page += 64;
}
/*
* Since movntq is weakly-ordered, a "sfence" is needed to become
* ordered again:
*/
__asm__ __volatile__("sfence\n"::);
kernel_fpu_end();
}
static void fast_copy_page(void *to, void *from)
{
int i;
kernel_fpu_begin_mask(KFPU_387);
/*
* maybe the prefetch stuff can go before the expensive fnsave...
* 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));
for (i = 0; i < (4096-320)/64; i++) {
__asm__ __volatile__ (
"1: prefetch 320(%0)\n"
"2: movq (%0), %%mm0\n"
" movntq %%mm0, (%1)\n"
" movq 8(%0), %%mm1\n"
" movntq %%mm1, 8(%1)\n"
" movq 16(%0), %%mm2\n"
" movntq %%mm2, 16(%1)\n"
" movq 24(%0), %%mm3\n"
" movntq %%mm3, 24(%1)\n"
" movq 32(%0), %%mm4\n"
" movntq %%mm4, 32(%1)\n"
" movq 40(%0), %%mm5\n"
" movntq %%mm5, 40(%1)\n"
" movq 48(%0), %%mm6\n"
" 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");
from += 64;
to += 64;
}
for (i = (4096-320)/64; i < 4096/64; i++) {
__asm__ __volatile__ (
"2: movq (%0), %%mm0\n"
" movntq %%mm0, (%1)\n"
" movq 8(%0), %%mm1\n"
" movntq %%mm1, 8(%1)\n"
" movq 16(%0), %%mm2\n"
" movntq %%mm2, 16(%1)\n"
" movq 24(%0), %%mm3\n"
" movntq %%mm3, 24(%1)\n"
" movq 32(%0), %%mm4\n"
" movntq %%mm4, 32(%1)\n"
" movq 40(%0), %%mm5\n"
" movntq %%mm5, 40(%1)\n"
" movq 48(%0), %%mm6\n"
" movntq %%mm6, 48(%1)\n"
" movq 56(%0), %%mm7\n"
" movntq %%mm7, 56(%1)\n"
: : "r" (from), "r" (to) : "memory");
from += 64;
to += 64;
}
/*
* Since movntq is weakly-ordered, a "sfence" is needed to become
* ordered again:
*/
__asm__ __volatile__("sfence \n"::);
kernel_fpu_end();
}
#else /* CONFIG_MK7 */
/*
* Generic MMX implementation without K7 specific streaming
*/
static void fast_clear_page(void *page)
{
int i;
kernel_fpu_begin_mask(KFPU_387);
__asm__ __volatile__ (
" pxor %%mm0, %%mm0\n" : :
);
for (i = 0; i < 4096/128; i++) {
__asm__ __volatile__ (
" movq %%mm0, (%0)\n"
" movq %%mm0, 8(%0)\n"
" movq %%mm0, 16(%0)\n"
" movq %%mm0, 24(%0)\n"
" movq %%mm0, 32(%0)\n"
" movq %%mm0, 40(%0)\n"
" movq %%mm0, 48(%0)\n"
" movq %%mm0, 56(%0)\n"
" movq %%mm0, 64(%0)\n"
" movq %%mm0, 72(%0)\n"
" movq %%mm0, 80(%0)\n"
" movq %%mm0, 88(%0)\n"
" movq %%mm0, 96(%0)\n"
" movq %%mm0, 104(%0)\n"
" movq %%mm0, 112(%0)\n"
" movq %%mm0, 120(%0)\n"
: : "r" (page) : "memory");
page += 128;
}
kernel_fpu_end();
}
static void fast_copy_page(void *to, void *from)
{
int i;
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));
for (i = 0; i < 4096/64; i++) {
__asm__ __volatile__ (
"1: prefetch 320(%0)\n"
"2: movq (%0), %%mm0\n"
" movq 8(%0), %%mm1\n"
" movq 16(%0), %%mm2\n"
" movq 24(%0), %%mm3\n"
" movq %%mm0, (%1)\n"
" movq %%mm1, 8(%1)\n"
" movq %%mm2, 16(%1)\n"
" movq %%mm3, 24(%1)\n"
" movq 32(%0), %%mm0\n"
" movq 40(%0), %%mm1\n"
" movq 48(%0), %%mm2\n"
" movq 56(%0), %%mm3\n"
" movq %%mm0, 32(%1)\n"
" 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;
to += 64;
}
kernel_fpu_end();
}
#endif /* !CONFIG_MK7 */
/*
* Favour MMX for page clear and copy:
*/
static void slow_zero_page(void *page)
{
int d0, d1;
__asm__ __volatile__(
"cld\n\t"
"rep ; stosl"
: "=&c" (d0), "=&D" (d1)
:"a" (0), "1" (page), "0" (1024)
:"memory");
}
void mmx_clear_page(void *page)
{
if (unlikely(in_interrupt()))
slow_zero_page(page);
else
fast_clear_page(page);
}
EXPORT_SYMBOL(mmx_clear_page);
static void slow_copy_page(void *to, void *from)
{
int d0, d1, d2;
__asm__ __volatile__(
"cld\n\t"
"rep ; movsl"
: "=&c" (d0), "=&D" (d1), "=&S" (d2)
: "0" (1024), "1" ((long) to), "2" ((long) from)
: "memory");
}
void mmx_copy_page(void *to, void *from)
{
if (unlikely(in_interrupt()))
slow_copy_page(to, from);
else
fast_copy_page(to, from);
}
EXPORT_SYMBOL(mmx_copy_page);

1
arch/x86/lib/usercopy_32.c
View File

@ -8,7 +8,6 @@
*/
#include <linux/export.h>
#include <linux/uaccess.h>
#include <asm/mmx.h>
#include <asm/asm.h>
#ifdef CONFIG_X86_INTEL_USERCOPY

4
tools/arch/x86/include/asm/required-features.h
View File

@ -35,11 +35,7 @@
# define NEED_CMOV 0
#endif
#ifdef CONFIG_X86_USE_3DNOW
# define NEED_3DNOW (1<<(X86_FEATURE_3DNOW & 31))
#else
# define NEED_3DNOW 0
#endif
#if defined(CONFIG_X86_P6_NOP) || defined(CONFIG_X86_64)
# define NEED_NOPL (1<<(X86_FEATURE_NOPL & 31))