![Andi Kleen](/assets/img/avatar_default.png)
- 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>
39 lines
646 B
ArmAsm
39 lines
646 B
ArmAsm
/* 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)
|