diff options
| author | David S. Miller <davem@davemloft.net> | 2012-10-27 23:00:41 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-10-27 23:00:41 -0700 |
| commit | e9b9eb59ffcdee09ec96b040f85c919618f4043e (patch) | |
| tree | 30f93cc20aa577ec5b12f609641fdf84d0bd5124 /arch/sparc/include/asm | |
| parent | 270c10e00a1e557e068803a22e0556281ceb1830 (diff) | |
sparc64: Use pause instruction when available.
In atomic backoff and cpu_relax(), use the pause instruction
found on SPARC-T4 and later.
It makes the cpu strand unselectable for the given number of
cycles, unless an intervening disrupting trap occurs.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/include/asm')
| -rw-r--r-- | arch/sparc/include/asm/backoff.h | 32 | ||||
| -rw-r--r-- | arch/sparc/include/asm/processor_64.h | 13 |
2 files changed, 29 insertions, 16 deletions
diff --git a/arch/sparc/include/asm/backoff.h b/arch/sparc/include/asm/backoff.h index 64b077b3b13b..20f01df0871b 100644 --- a/arch/sparc/include/asm/backoff.h +++ b/arch/sparc/include/asm/backoff.h @@ -11,19 +11,25 @@ #define BACKOFF_LABEL(spin_label, continue_label) \ spin_label -#define BACKOFF_SPIN(reg, tmp, label) \ - mov reg, tmp; \ -88: rd %ccr, %g0; \ - rd %ccr, %g0; \ - rd %ccr, %g0; \ - brnz,pt tmp, 88b; \ - sub tmp, 1, tmp; \ - set BACKOFF_LIMIT, tmp; \ - cmp reg, tmp; \ - bg,pn %xcc, label; \ - nop; \ - ba,pt %xcc, label; \ - sllx reg, 1, reg; +#define BACKOFF_SPIN(reg, tmp, label) \ + mov reg, tmp; \ +88: rd %ccr, %g0; \ + rd %ccr, %g0; \ + rd %ccr, %g0; \ + .section .pause_patch,"ax"; \ + .word 88b; \ + sllx tmp, 7, tmp; \ + wr tmp, 0, %asr27; \ + clr tmp; \ + .previous; \ + brnz,pt tmp, 88b; \ + sub tmp, 1, tmp; \ + set BACKOFF_LIMIT, tmp; \ + cmp reg, tmp; \ + bg,pn %xcc, label; \ + nop; \ + ba,pt %xcc, label; \ + sllx reg, 1, reg; #else diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h index 986563409469..9cdf52eec48a 100644 --- a/arch/sparc/include/asm/processor_64.h +++ b/arch/sparc/include/asm/processor_64.h @@ -196,9 +196,16 @@ extern unsigned long get_wchan(struct task_struct *task); #define KSTK_EIP(tsk) (task_pt_regs(tsk)->tpc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->u_regs[UREG_FP]) -#define cpu_relax() asm volatile("rd %%ccr, %%g0\n\t" \ - "rd %%ccr, %%g0\n\t" \ - "rd %%ccr, %%g0" \ +#define cpu_relax() asm volatile("\n99:\n\t" \ + "rd %%ccr, %%g0\n\t" \ + "rd %%ccr, %%g0\n\t" \ + "rd %%ccr, %%g0\n\t" \ + ".section .pause_patch,\"ax\"\n\t"\ + ".word 99b\n\t" \ + "wr %%g0, 128, %%asr27\n\t" \ + "nop\n\t" \ + "nop\n\t" \ + ".previous" \ ::: "memory") /* Prefetch support. This is tuned for UltraSPARC-III and later. |