Commit-ID: f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9 Gitweb: http://git.kernel.org/tip/f7f3dc00f61261cdc9ccd8b886f21bc4dffd6fd9 Author: Borislav Petkov <b...@suse.de> AuthorDate: Thu, 7 Sep 2017 19:08:21 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 15 Sep 2017 11:30:53 +0200
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 <b...@suse.de> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Sherry Hurwitz <sherry.hurw...@amd.com> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/20170907170821.16021-1...@alien8.de Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/kernel/cpu/amd.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 9862e2c..d58184b 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 */
