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[PATCH] i386: Remove alternative_smp

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The .fill causes miscompilations with some binutils version.

Instead just patch the lock prefix in the lock constructs. That is the
majority of the cost and should be good enough.

Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2006-08-30 19:37:14 +02:00 committed by Linus Torvalds
parent 841be8ddf9
commit 8c74932779
3 changed files with 10 additions and 41 deletions
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20
include/asm-i386/alternative.h
View File

@ -88,9 +88,6 @@ static inline void alternatives_smp_switch(int smp) {}
/*
* Alternative inline assembly for SMP.
*
* alternative_smp() takes two versions (SMP first, UP second) and is
* for more complex stuff such as spinlocks.
*
* The LOCK_PREFIX macro defined here replaces the LOCK and
* LOCK_PREFIX macros used everywhere in the source tree.
*
@ -110,21 +107,6 @@ static inline void alternatives_smp_switch(int smp) {}
*/
#ifdef CONFIG_SMP
#define alternative_smp(smpinstr, upinstr, args...) \
asm volatile ("661:\n\t" smpinstr "\n662:\n" \
".section .smp_altinstructions,\"a\"\n" \
" .align 4\n" \
" .long 661b\n" /* label */ \
" .long 663f\n" /* new instruction */ \
" .byte " __stringify(X86_FEATURE_UP) "\n" \
" .byte 662b-661b\n" /* sourcelen */ \
" .byte 664f-663f\n" /* replacementlen */ \
".previous\n" \
".section .smp_altinstr_replacement,\"awx\"\n" \
"663:\n\t" upinstr "\n" /* replacement */ \
"664:\n\t.fill 662b-661b,1,0x42\n" /* space for original */ \
".previous" : args)
#define LOCK_PREFIX \
".section .smp_locks,\"a\"\n" \
" .align 4\n" \
@ -133,8 +115,6 @@ static inline void alternatives_smp_switch(int smp) {}
"661:\n\tlock; "
#else /* ! CONFIG_SMP */
#define alternative_smp(smpinstr, upinstr, args...) \
asm volatile (upinstr : args)
#define LOCK_PREFIX ""
#endif

14
include/asm-i386/rwlock.h
View File

@ -21,22 +21,20 @@
#define RW_LOCK_BIAS_STR "0x01000000"
#define __build_read_lock_ptr(rw, helper) \
alternative_smp("lock; subl $1,(%0)\n\t" \
asm volatile(LOCK_PREFIX " ; subl $1,(%0)\n\t" \
"jns 1f\n" \
"call " helper "\n\t" \
"1:\n", \
"subl $1,(%0)\n\t", \
"1:\n" \
:"a" (rw) : "memory")
#define __build_read_lock_const(rw, helper) \
alternative_smp("lock; subl $1,%0\n\t" \
asm volatile(LOCK_PREFIX " ; subl $1,%0\n\t" \
"jns 1f\n" \
"pushl %%eax\n\t" \
"leal %0,%%eax\n\t" \
"call " helper "\n\t" \
"popl %%eax\n\t" \
"1:\n", \
"subl $1,%0\n\t", \
"1:\n" : \
"+m" (*(volatile int *)rw) : : "memory")
#define __build_read_lock(rw, helper) do { \
@ -47,7 +45,7 @@
} while (0)
#define __build_write_lock_ptr(rw, helper) \
alternative_smp("lock; subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
asm volatile(LOCK_PREFIX " ; subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
"jz 1f\n" \
"call " helper "\n\t" \
"1:\n", \
@ -55,7 +53,7 @@
:"a" (rw) : "memory")
#define __build_write_lock_const(rw, helper) \
alternative_smp("lock; subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
asm volatile(LOCK_PREFIX " ; subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
"jz 1f\n" \
"pushl %%eax\n\t" \
"leal %0,%%eax\n\t" \

17
include/asm-i386/spinlock.h
View File

@ -22,7 +22,7 @@
#define __raw_spin_lock_string \
"\n1:\t" \
"lock ; decb %0\n\t" \
LOCK_PREFIX " ; decb %0\n\t" \
"jns 3f\n" \
"2:\t" \
"rep;nop\n\t" \
@ -38,7 +38,7 @@
*/
#define __raw_spin_lock_string_flags \
"\n1:\t" \
"lock ; decb %0\n\t" \
LOCK_PREFIX " ; decb %0\n\t" \
"jns 5f\n" \
"2:\t" \
"testl $0x200, %1\n\t" \
@ -57,15 +57,9 @@
"jmp 4b\n" \
"5:\n\t"
#define __raw_spin_lock_string_up \
"\n\tdecb %0"
static inline void __raw_spin_lock(raw_spinlock_t *lock)
{
alternative_smp(
__raw_spin_lock_string,
__raw_spin_lock_string_up,
"+m" (lock->slock) : : "memory");
asm(__raw_spin_lock_string : "+m" (lock->slock) : : "memory");
}
/*
@ -76,10 +70,7 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
#ifndef CONFIG_PROVE_LOCKING
static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
{
alternative_smp(
__raw_spin_lock_string_flags,
__raw_spin_lock_string_up,
"+m" (lock->slock) : "r" (flags) : "memory");
asm(__raw_spin_lock_string_flags : "+m" (lock->slock) : "r" (flags) : "memory");
}
#endif