diff options
| author | Andi Kleen <ak@suse.de> | 2006-09-26 10:52:28 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 10:52:28 +0200 |
| commit | 9a0b26e6bc4ae1979d9bcc6194e57a71b2b5cac6 (patch) | |
| tree | 01601a502007b85d4fc88f79de7a93c257ef9d97 /include/asm-x86_64/rwlock.h | |
| parent | b4062b16094038334d9bbadac0397a3fc9e981b0 (diff) | |
[PATCH] Clean up read write lock assembly
- Move the slow path fallbacks to their own assembly files
This makes them much easier to read and is needed for the next change.
- Add CFI annotations for unwinding (XXX need review)
- Remove constant case which can never happen with out of line spinlocks
- Use patchable LOCK prefixes
- Don't use lock sections anymore for inline code because they can't
be expressed by the unwinder (this adds one taken jump to the lock
fast path)
Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/asm-x86_64/rwlock.h')
| -rw-r--r-- | include/asm-x86_64/rwlock.h | 68 |
1 files changed, 10 insertions, 58 deletions
diff --git a/include/asm-x86_64/rwlock.h b/include/asm-x86_64/rwlock.h index dea0e9459264..28a080d23119 100644 --- a/include/asm-x86_64/rwlock.h +++ b/include/asm-x86_64/rwlock.h @@ -18,69 +18,21 @@ #ifndef _ASM_X86_64_RWLOCK_H #define _ASM_X86_64_RWLOCK_H -#include <linux/stringify.h> - #define RW_LOCK_BIAS 0x01000000 -#define RW_LOCK_BIAS_STR "0x01000000" +#define RW_LOCK_BIAS_STR "0x01000000" -#define __build_read_lock_ptr(rw, helper) \ +#define __build_read_lock(rw) \ asm volatile(LOCK_PREFIX "subl $1,(%0)\n\t" \ - "js 2f\n" \ - "1:\n" \ - LOCK_SECTION_START("") \ - "2:\tcall " helper "\n\t" \ - "jmp 1b\n" \ - LOCK_SECTION_END \ - ::"a" (rw) : "memory") - -#define __build_read_lock_const(rw, helper) \ - asm volatile(LOCK_PREFIX "subl $1,%0\n\t" \ - "js 2f\n" \ + "jns 1f\n" \ + "call __read_lock_failed\n" \ "1:\n" \ - LOCK_SECTION_START("") \ - "2:\tpushq %%rax\n\t" \ - "leaq %0,%%rax\n\t" \ - "call " helper "\n\t" \ - "popq %%rax\n\t" \ - "jmp 1b\n" \ - LOCK_SECTION_END \ - :"=m" (*((volatile int *)rw))::"memory") - -#define __build_read_lock(rw, helper) do { \ - if (__builtin_constant_p(rw)) \ - __build_read_lock_const(rw, helper); \ - else \ - __build_read_lock_ptr(rw, helper); \ - } while (0) + ::"D" (rw), "i" (RW_LOCK_BIAS) : "memory") -#define __build_write_lock_ptr(rw, helper) \ - asm volatile(LOCK_PREFIX "subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \ - "jnz 2f\n" \ +#define __build_write_lock(rw) \ + asm volatile(LOCK_PREFIX "subl %1,(%0)\n\t" \ + "jz 1f\n" \ + "\tcall __write_lock_failed\n\t" \ "1:\n" \ - LOCK_SECTION_START("") \ - "2:\tcall " helper "\n\t" \ - "jmp 1b\n" \ - LOCK_SECTION_END \ - ::"a" (rw) : "memory") - -#define __build_write_lock_const(rw, helper) \ - asm volatile(LOCK_PREFIX "subl $" RW_LOCK_BIAS_STR ",%0\n\t" \ - "jnz 2f\n" \ - "1:\n" \ - LOCK_SECTION_START("") \ - "2:\tpushq %%rax\n\t" \ - "leaq %0,%%rax\n\t" \ - "call " helper "\n\t" \ - "popq %%rax\n\t" \ - "jmp 1b\n" \ - LOCK_SECTION_END \ - :"=m" (*((volatile long *)rw))::"memory") - -#define __build_write_lock(rw, helper) do { \ - if (__builtin_constant_p(rw)) \ - __build_write_lock_const(rw, helper); \ - else \ - __build_write_lock_ptr(rw, helper); \ - } while (0) + ::"D" (rw), "i" (RW_LOCK_BIAS) : "memory") #endif |