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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-11-16 18:21:36 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-11-16 18:21:36 -0800 |
| commit | 98c4514ff6e3072288770db66f91bdb15af8b433 (patch) | |
| tree | eb5f2541e70d27144720e1735b463471025908f0 /arch/sparc/include/asm/processor_64.h | |
| parent | 644a9d3b66e6983c2c1f3b24c3006d49b184c871 (diff) | |
| parent | f4a75d2eb7b1e2206094b901be09adb31ba63681 (diff) | |
| download | talos-op-linux-98c4514ff6e3072288770db66f91bdb15af8b433.tar.gz talos-op-linux-98c4514ff6e3072288770db66f91bdb15af8b433.zip | |
Merge 3.7-rc6 into char-misc-next
Diffstat (limited to 'arch/sparc/include/asm/processor_64.h')
| -rw-r--r-- | arch/sparc/include/asm/processor_64.h | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h index 4e5a483122a0..721e25f0e2ea 100644 --- a/arch/sparc/include/asm/processor_64.h +++ b/arch/sparc/include/asm/processor_64.h @@ -196,7 +196,22 @@ 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() barrier() +/* Please see the commentary in asm/backoff.h for a description of + * what these instructions are doing and how they have been choosen. + * To make a long story short, we are trying to yield the current cpu + * strand during busy loops. + */ +#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_3insn_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. * UltraSPARC-I will treat these as nops, and UltraSPARC-II has |
