diff options
| author | Jan Beulich <JBeulich@novell.com> | 2011-07-19 12:59:51 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-07-21 09:03:31 +0200 |
| commit | 4625cd637919edfb562e0d62abf94f52e9321335 (patch) | |
| tree | 88c4cf965722fb54731a6e8f632ec6ef6e83e194 /arch/x86/lib/rwlock.S | |
| parent | dd2897bf0f4d523238e87dabb23e9634ea9ba73d (diff) | |
x86: Unify rwlock assembly implementation
Rather than having two functionally identical implementations
for 32- and 64-bit configurations, extend the existing assembly
abstractions enough to fold the two rwlock implementations into
a shared one.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4E258DD7020000780004E3EA@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/lib/rwlock.S')
| -rw-r--r-- | arch/x86/lib/rwlock.S | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/x86/lib/rwlock.S b/arch/x86/lib/rwlock.S new file mode 100644 index 00000000000..fca17829caa --- /dev/null +++ b/arch/x86/lib/rwlock.S @@ -0,0 +1,44 @@ +/* Slow paths of read/write spinlocks. */ + +#include <linux/linkage.h> +#include <asm/alternative-asm.h> +#include <asm/frame.h> +#include <asm/rwlock.h> + +#ifdef CONFIG_X86_32 +# define __lock_ptr eax +#else +# define __lock_ptr rdi +#endif + +ENTRY(__write_lock_failed) + CFI_STARTPROC + FRAME +0: LOCK_PREFIX + addl $RW_LOCK_BIAS, (%__lock_ptr) +1: rep; nop + cmpl $RW_LOCK_BIAS, (%__lock_ptr) + jne 1b + LOCK_PREFIX + subl $RW_LOCK_BIAS, (%__lock_ptr) + jnz 0b + ENDFRAME + ret + CFI_ENDPROC +END(__write_lock_failed) + +ENTRY(__read_lock_failed) + CFI_STARTPROC + FRAME +0: LOCK_PREFIX + incl (%__lock_ptr) +1: rep; nop + cmpl $1, (%__lock_ptr) + js 1b + LOCK_PREFIX + decl (%__lock_ptr) + js 0b + ENDFRAME + ret + CFI_ENDPROC +END(__read_lock_failed) |