diff options
| author | Andi Kleen <ak@suse.de> | 2006-09-26 12:52:28 +0400 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 12:52:28 +0400 |
| commit | 9a0b26e6bc4ae1979d9bcc6194e57a71b2b5cac6 (patch) | |
| tree | 01601a502007b85d4fc88f79de7a93c257ef9d97 /arch/x86_64/lib | |
| parent | b4062b16094038334d9bbadac0397a3fc9e981b0 (diff) | |
| download | linux-9a0b26e6bc4ae1979d9bcc6194e57a71b2b5cac6.tar.xz | |
[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 'arch/x86_64/lib')
| -rw-r--r-- | arch/x86_64/lib/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86_64/lib/rwlock.S | 38 | ||||
| -rw-r--r-- | arch/x86_64/lib/thunk.S | 30 |
3 files changed, 39 insertions, 31 deletions
diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile index ccef6ae747a3..b78d4170fce2 100644 --- a/arch/x86_64/lib/Makefile +++ b/arch/x86_64/lib/Makefile @@ -9,4 +9,4 @@ obj-y := io.o iomap_copy.o lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \ usercopy.o getuser.o putuser.o \ thunk.o clear_page.o copy_page.o bitstr.o bitops.o -lib-y += memcpy.o memmove.o memset.o copy_user.o +lib-y += memcpy.o memmove.o memset.o copy_user.o rwlock.o diff --git a/arch/x86_64/lib/rwlock.S b/arch/x86_64/lib/rwlock.S new file mode 100644 index 000000000000..0cde1f807314 --- /dev/null +++ b/arch/x86_64/lib/rwlock.S @@ -0,0 +1,38 @@ +/* Slow paths of read/write spinlocks. */ + +#include <linux/linkage.h> +#include <asm/rwlock.h> +#include <asm/alternative-asm.i> +#include <asm/dwarf2.h> + +/* rdi: pointer to rwlock_t */ +ENTRY(__write_lock_failed) + CFI_STARTPROC + LOCK_PREFIX + addl $RW_LOCK_BIAS,(%rdi) +1: rep + nop + cmpl $RW_LOCK_BIAS,(%rdi) + jne 1b + LOCK_PREFIX + subl $RW_LOCK_BIAS,(%rdi) + jnz __write_lock_failed + ret + CFI_ENDPROC +END(__write_lock_failed) + +/* rdi: pointer to rwlock_t */ +ENTRY(__read_lock_failed) + CFI_STARTPROC + LOCK_PREFIX + incl (%rdi) +1: rep + nop + cmpl $1,(%rdi) + js 1b + LOCK_PREFIX + decl (%rdi) + js __read_lock_failed + ret + CFI_ENDPROC +END(__read_lock_failed) diff --git a/arch/x86_64/lib/thunk.S b/arch/x86_64/lib/thunk.S index 332ea5dff916..6cff27c775ae 100644 --- a/arch/x86_64/lib/thunk.S +++ b/arch/x86_64/lib/thunk.S @@ -67,33 +67,3 @@ restore_norax: RESTORE_ARGS 1 ret CFI_ENDPROC - -#ifdef CONFIG_SMP -/* Support for read/write spinlocks. */ - .text -/* rax: pointer to rwlock_t */ -ENTRY(__write_lock_failed) - lock - addl $RW_LOCK_BIAS,(%rax) -1: rep - nop - cmpl $RW_LOCK_BIAS,(%rax) - jne 1b - lock - subl $RW_LOCK_BIAS,(%rax) - jnz __write_lock_failed - ret - -/* rax: pointer to rwlock_t */ -ENTRY(__read_lock_failed) - lock - incl (%rax) -1: rep - nop - cmpl $1,(%rax) - js 1b - lock - decl (%rax) - js __read_lock_failed - ret -#endif |