4.9-stable review patch. If anyone has any objections, please let me know.
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From: Borislav Petkov bp@suse.de
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 --- arch/x86/kernel/cpu/amd.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
--- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -749,6 +749,16 @@ static void init_amd_bd(struct cpuinfo_x } }
+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_stepping <= 1) + set_cpu_cap(c, X86_FEATURE_CPB); +} + static void init_amd(struct cpuinfo_x86 *c) { u32 dummy; @@ -779,6 +789,7 @@ static void init_amd(struct cpuinfo_x86 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 */