arch/x86/lib/rwlock.S

   1 /* Slow paths of read/write spinlocks. */
   2
   3 #include <linux/linkage.h>
   4 #include <asm/alternative-asm.h>
   5 #include <asm/frame.h>
   6 #include <asm/rwlock.h>
   7
   8 #ifdef CONFIG_X86_32
   9 # define __lock_ptr eax
  10 #else
  11 # define __lock_ptr rdi
  12 #endif
  13
  14 ENTRY(__write_lock_failed)
  15         CFI_STARTPROC
  16         FRAME
  17 0:      LOCK_PREFIX
  18         WRITE_LOCK_ADD($RW_LOCK_BIAS) (%__lock_ptr)
  19 1:      rep; nop
  20         cmpl    $WRITE_LOCK_CMP, (%__lock_ptr)
  21         jne     1b
  22         LOCK_PREFIX
  23         WRITE_LOCK_SUB($RW_LOCK_BIAS) (%__lock_ptr)
  24         jnz     0b
  25         ENDFRAME
  26         ret
  27         CFI_ENDPROC
  28 END(__write_lock_failed)
  29
  30 ENTRY(__read_lock_failed)
  31         CFI_STARTPROC
  32         FRAME
  33 0:      LOCK_PREFIX
  34         READ_LOCK_SIZE(inc) (%__lock_ptr)
  35 1:      rep; nop
  36         READ_LOCK_SIZE(cmp) $1, (%__lock_ptr)
  37         js      1b
  38         LOCK_PREFIX
  39         READ_LOCK_SIZE(dec) (%__lock_ptr)
  40         js      0b
  41         ENDFRAME
  42         ret
  43         CFI_ENDPROC
  44 END(__read_lock_failed)