[PATCH] i386: Remove lock section support in rwsem.h
Lock sections don't work the new dwarf2 unwinder
This generates slightly smaller code. It adds one more taken
jump to the fast path.
Also move the trampolines into semaphore.S and add proper CFI
annotations.
Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/include/asm-i386/rwsem.h b/include/asm-i386/rwsem.h
index 43113f5..bc598d6 100644
--- a/include/asm-i386/rwsem.h
+++ b/include/asm-i386/rwsem.h
@@ -99,17 +99,9 @@
__asm__ __volatile__(
"# beginning down_read\n\t"
LOCK_PREFIX " incl (%%eax)\n\t" /* adds 0x00000001, returns the old value */
- " js 2f\n\t" /* jump if we weren't granted the lock */
+ " jns 1f\n"
+ " call call_rwsem_down_read_failed\n"
"1:\n\t"
- LOCK_SECTION_START("")
- "2:\n\t"
- " pushl %%ecx\n\t"
- " pushl %%edx\n\t"
- " call rwsem_down_read_failed\n\t"
- " popl %%edx\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- LOCK_SECTION_END
"# ending down_read\n\t"
: "+m" (sem->count)
: "a" (sem)
@@ -151,15 +143,9 @@
"# beginning down_write\n\t"
LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtract 0x0000ffff, returns the old value */
" testl %%edx,%%edx\n\t" /* was the count 0 before? */
- " jnz 2f\n\t" /* jump if we weren't granted the lock */
- "1:\n\t"
- LOCK_SECTION_START("")
- "2:\n\t"
- " pushl %%ecx\n\t"
- " call rwsem_down_write_failed\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- LOCK_SECTION_END
+ " jz 1f\n"
+ " call call_rwsem_down_write_failed\n"
+ "1:\n"
"# ending down_write"
: "+m" (sem->count), "=d" (tmp)
: "a" (sem), "1" (tmp)
@@ -193,17 +179,9 @@
__asm__ __volatile__(
"# beginning __up_read\n\t"
LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtracts 1, returns the old value */
- " js 2f\n\t" /* jump if the lock is being waited upon */
- "1:\n\t"
- LOCK_SECTION_START("")
- "2:\n\t"
- " decw %%dx\n\t" /* do nothing if still outstanding active readers */
- " jnz 1b\n\t"
- " pushl %%ecx\n\t"
- " call rwsem_wake\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- LOCK_SECTION_END
+ " jns 1f\n\t"
+ " call call_rwsem_wake\n"
+ "1:\n"
"# ending __up_read\n"
: "+m" (sem->count), "=d" (tmp)
: "a" (sem), "1" (tmp)
@@ -219,17 +197,9 @@
"# beginning __up_write\n\t"
" movl %2,%%edx\n\t"
LOCK_PREFIX " xaddl %%edx,(%%eax)\n\t" /* tries to transition 0xffff0001 -> 0x00000000 */
- " jnz 2f\n\t" /* jump if the lock is being waited upon */
+ " jz 1f\n"
+ " call call_rwsem_wake\n"
"1:\n\t"
- LOCK_SECTION_START("")
- "2:\n\t"
- " decw %%dx\n\t" /* did the active count reduce to 0? */
- " jnz 1b\n\t" /* jump back if not */
- " pushl %%ecx\n\t"
- " call rwsem_wake\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- LOCK_SECTION_END
"# ending __up_write\n"
: "+m" (sem->count)
: "a" (sem), "i" (-RWSEM_ACTIVE_WRITE_BIAS)
@@ -244,17 +214,9 @@
__asm__ __volatile__(
"# beginning __downgrade_write\n\t"
LOCK_PREFIX " addl %2,(%%eax)\n\t" /* transitions 0xZZZZ0001 -> 0xYYYY0001 */
- " js 2f\n\t" /* jump if the lock is being waited upon */
+ " jns 1f\n\t"
+ " call call_rwsem_downgrade_wake\n"
"1:\n\t"
- LOCK_SECTION_START("")
- "2:\n\t"
- " pushl %%ecx\n\t"
- " pushl %%edx\n\t"
- " call rwsem_downgrade_wake\n\t"
- " popl %%edx\n\t"
- " popl %%ecx\n\t"
- " jmp 1b\n"
- LOCK_SECTION_END
"# ending __downgrade_write\n"
: "+m" (sem->count)
: "a" (sem), "i" (-RWSEM_WAITING_BIAS)