diff options
| author | Borislav Petkov <bp@suse.de> | 2017-09-07 19:08:21 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-09-25 23:47:35 +0100 |
| commit | 5abd1583e06b3963e5c9d915760367de86808b78 (patch) | |
| tree | cf004d96d3063d0aca9a5cfe380eb78a4b9ebd51 | |
| parent | a5e7e187aef0a25aaed6820e6664d1cc4f99c876 (diff) | |
x86/cpu/AMD: Fix erratum 1076 (CPB bit)
commit f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9 upstream.
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>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.16:
- Change the added case into an if-statement
- s/x86_stepping/x86_mask/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 2b597d03d5ed..ae2832700bb5 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -533,6 +533,16 @@ static void init_amd_ln(struct cpuinfo_x86 *c) msr_set_bit(MSR_AMD64_DE_CFG, 31); } +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) { u32 dummy; @@ -611,6 +621,9 @@ static void init_amd(struct cpuinfo_x86 *c) clear_cpu_cap(c, X86_FEATURE_MCE); #endif + if (c->x86 == 0x17) + init_amd_zn(c); + /* Enable workaround for FXSAVE leak */ if (c->x86 >= 6) set_cpu_cap(c, X86_FEATURE_FXSAVE_LEAK); |