arch/sparc/lib/atomic.S

   1 /* atomic.S: Move this stuff here for better ICACHE hit rates.
   2  *
   3  * Copyright (C) 1996 David S. Miller (davem@caipfs.rutgers.edu)
   4  */
   5
   6 #include <linux/config.h>
   7 #include <asm/ptrace.h>
   8 #include <asm/psr.h>
   9
  10         .text
  11         .align  4
  12
  13         .globl  __atomic_begin
  14 __atomic_begin:
  15
  16 #ifndef CONFIG_SMP
  17         .globl  ___xchg32_sun4c
  18 ___xchg32_sun4c:
  19         rd      %psr, %g3
  20         andcc   %g3, PSR_PIL, %g0
  21         bne     1f
  22          nop
  23         wr      %g3, PSR_PIL, %psr
  24         nop; nop; nop
  25 1:
  26         andcc   %g3, PSR_PIL, %g0
  27         ld      [%g1], %g7
  28         bne     1f
  29          st     %g2, [%g1]
  30         wr      %g3, 0x0, %psr
  31         nop; nop; nop
  32 1:
  33         mov     %g7, %g2
  34         jmpl    %o7 + 8, %g0
  35          mov    %g4, %o7
  36
  37         .globl  ___xchg32_sun4md
  38 ___xchg32_sun4md:
  39         swap    [%g1], %g2
  40         jmpl    %o7 + 8, %g0
  41          mov    %g4, %o7
  42 #endif
  43
  44         /* Read asm-sparc/atomic.h carefully to understand how this works for SMP.
  45          * Really, some things here for SMP are overly clever, go read the header.
  46          */
  47         .globl  ___atomic24_add
  48 ___atomic24_add:
  49         rd      %psr, %g3               ! Keep the code small, old way was stupid
  50         nop; nop; nop;                  ! Let the bits set
  51         or      %g3, PSR_PIL, %g7       ! Disable interrupts
  52         wr      %g7, 0x0, %psr          ! Set %psr
  53         nop; nop; nop;                  ! Let the bits set
  54 #ifdef CONFIG_SMP
  55 1:      ldstub  [%g1 + 3], %g7          ! Spin on the byte lock for SMP.
  56         orcc    %g7, 0x0, %g0           ! Did we get it?
  57         bne     1b                      ! Nope...
  58          ld     [%g1], %g7              ! Load locked atomic24_t
  59         sra     %g7, 8, %g7             ! Get signed 24-bit integer
  60         add     %g7, %g2, %g2           ! Add in argument
  61         sll     %g2, 8, %g7             ! Transpose back to atomic24_t
  62         st      %g7, [%g1]              ! Clever: This releases the lock as well.
  63 #else
  64         ld      [%g1], %g7              ! Load locked atomic24_t
  65         add     %g7, %g2, %g2           ! Add in argument
  66         st      %g2, [%g1]              ! Store it back
  67 #endif
  68         wr      %g3, 0x0, %psr          ! Restore original PSR_PIL
  69         nop; nop; nop;                  ! Let the bits set
  70         jmpl    %o7, %g0                ! NOTE: not + 8, see callers in atomic.h
  71          mov    %g4, %o7                ! Restore %o7
  72
  73         .globl  ___atomic24_sub
  74 ___atomic24_sub:
  75         rd      %psr, %g3               ! Keep the code small, old way was stupid
  76         nop; nop; nop;                  ! Let the bits set
  77         or      %g3, PSR_PIL, %g7       ! Disable interrupts
  78         wr      %g7, 0x0, %psr          ! Set %psr
  79         nop; nop; nop;                  ! Let the bits set
  80 #ifdef CONFIG_SMP
  81 1:      ldstub  [%g1 + 3], %g7          ! Spin on the byte lock for SMP.
  82         orcc    %g7, 0x0, %g0           ! Did we get it?
  83         bne     1b                      ! Nope...
  84          ld     [%g1], %g7              ! Load locked atomic24_t
  85         sra     %g7, 8, %g7             ! Get signed 24-bit integer
  86         sub     %g7, %g2, %g2           ! Subtract argument
  87         sll     %g2, 8, %g7             ! Transpose back to atomic24_t
  88         st      %g7, [%g1]              ! Clever: This releases the lock as well
  89 #else
  90         ld      [%g1], %g7              ! Load locked atomic24_t
  91         sub     %g7, %g2, %g2           ! Subtract argument
  92         st      %g2, [%g1]              ! Store it back
  93 #endif
  94         wr      %g3, 0x0, %psr          ! Restore original PSR_PIL
  95         nop; nop; nop;                  ! Let the bits set
  96         jmpl    %o7, %g0                ! NOTE: not + 8, see callers in atomic.h
  97          mov    %g4, %o7                ! Restore %o7
  98
  99         .globl  __atomic_end
 100 __atomic_end: