diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2012-11-16 22:28:43 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-11-16 22:28:43 -0500 |
| commit | 2bf81c8af92dd53890557c5d87875842d573a3e9 (patch) | |
| tree | 83e7e3539599b091ac69557658c06c0a39cfa60e /arch/sparc/include/asm/processor_64.h | |
| parent | 9526d9bc23f362035cfabf044aa90f4ed1787955 (diff) | |
| parent | 5f6c4ab6ee781c9aace7c8548ad9bd87f5678df7 (diff) | |
Merge branch 'arch-microblaze' into no-rebases
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 0305d56d9b1a..cce72ce4c334 100644 --- a/arch/sparc/include/asm/processor_64.h +++ b/arch/sparc/include/asm/processor_64.h @@ -203,7 +203,22 @@ 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 |