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| 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/kernel/setup_64.c | |
| parent | sparc64: Fix cpu strand yielding. (diff) | |
| download | linux-dev-e9b9eb59ffcdee09ec96b040f85c919618f4043e.tar.xz linux-dev-e9b9eb59ffcdee09ec96b040f85c919618f4043e.zip | |
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/kernel/setup_64.c')
| -rw-r--r-- | arch/sparc/kernel/setup_64.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c index 0800e71d8a88..b45cff408de3 100644 --- a/arch/sparc/kernel/setup_64.c +++ b/arch/sparc/kernel/setup_64.c @@ -316,6 +316,25 @@ static void __init popc_patch(void) } } +static void __init pause_patch(void) +{ + struct pause_patch_entry *p; + + p = &__pause_patch; + while (p < &__pause_patch_end) { + unsigned long i, addr = p->addr; + + for (i = 0; i < 3; i++) { + *(unsigned int *) (addr + (i * 4)) = p->insns[i]; + wmb(); + __asm__ __volatile__("flush %0" + : : "r" (addr + (i * 4))); + } + + p++; + } +} + #ifdef CONFIG_SMP void __init boot_cpu_id_too_large(int cpu) { @@ -528,6 +547,8 @@ static void __init init_sparc64_elf_hwcap(void) if (sparc64_elf_hwcap & AV_SPARC_POPC) popc_patch(); + if (sparc64_elf_hwcap & AV_SPARC_PAUSE) + pause_patch(); } void __init setup_arch(char **cmdline_p) |