diff options
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 000000000000..1cad22139c88 --- /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 + WRITE_LOCK_ADD($RW_LOCK_BIAS) (%__lock_ptr) +1: rep; nop + cmpl $WRITE_LOCK_CMP, (%__lock_ptr) + jne 1b + LOCK_PREFIX + WRITE_LOCK_SUB($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 + READ_LOCK_SIZE(inc) (%__lock_ptr) +1: rep; nop + READ_LOCK_SIZE(cmp) $1, (%__lock_ptr) + js 1b + LOCK_PREFIX + READ_LOCK_SIZE(dec) (%__lock_ptr) + js 0b + ENDFRAME + ret + CFI_ENDPROC +END(__read_lock_failed) |