diff options
Diffstat (limited to 'arch/x86_64/lib/rwlock_64.S')
| -rw-r--r-- | arch/x86_64/lib/rwlock_64.S | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/x86_64/lib/rwlock_64.S b/arch/x86_64/lib/rwlock_64.S new file mode 100644 index 00000000000..0cde1f80731 --- /dev/null +++ b/arch/x86_64/lib/rwlock_64.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) |