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| author | Borislav Petkov <bp@suse.de> | 2017-09-07 19:08:21 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-09-15 11:30:53 +0200 |
| commit | f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9 (patch) | |
| tree | 7891c49328f3ca3eb3fad5f7334535da980e55be /arch/x86/kernel | |
| parent | vfs: constify path argument to kernel_read_file_from_path (diff) | |
| download | linux-f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9.tar.xz linux-f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9.zip | |
x86/cpu/AMD: Fix erratum 1076 (CPB bit)
CPUID Fn8000_0007_EDX[CPB] is wrongly 0 on models up to B1. But they do
support CPB (AMD's Core Performance Boosting cpufreq CPU feature), so fix that.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sherry Hurwitz <sherry.hurwitz@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170907170821.16021-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 9862e2cd6d93..d58184b7cd44 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -763,6 +763,16 @@ static void init_amd_bd(struct cpuinfo_x86 *c) } } +static void init_amd_zn(struct cpuinfo_x86 *c) +{ + /* + * Fix erratum 1076: CPB feature bit not being set in CPUID. It affects + * all up to and including B1. + */ + if (c->x86_model <= 1 && c->x86_mask <= 1) + set_cpu_cap(c, X86_FEATURE_CPB); +} + static void init_amd(struct cpuinfo_x86 *c) { early_init_amd(c); @@ -791,6 +801,7 @@ static void init_amd(struct cpuinfo_x86 *c) case 0x10: init_amd_gh(c); break; case 0x12: init_amd_ln(c); break; case 0x15: init_amd_bd(c); break; + case 0x17: init_amd_zn(c); break; } /* Enable workaround for FXSAVE leak */ |