4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiaxun Yang jiaxun.yang@flygoat.com
commit 0237199186e7a4aa5310741f0a6498a20c820fd7 upstream.
Some F17h models do not have CPB set in CPUID even though the CPU supports it. Set the feature bit unconditionally on all F17h.
[ bp: Rewrite commit message and patch. ]
Signed-off-by: Jiaxun Yang jiaxun.yang@flygoat.com Signed-off-by: Borislav Petkov bp@suse.de Acked-by: Tom Lendacky thomas.lendacky@amd.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@redhat.com Cc: Sherry Hurwitz sherry.hurwitz@amd.com Cc: Suravee Suthikulpanit suravee.suthikulpanit@amd.com Cc: Thomas Gleixner tglx@linutronix.de Cc: x86-ml x86@kernel.org Link: https://lkml.kernel.org/r/20181120030018.5185-1-jiaxun.yang@flygoat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/cpu/amd.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -716,11 +716,9 @@ static void init_amd_bd(struct cpuinfo_x static void init_amd_zn(struct cpuinfo_x86 *c) { set_cpu_cap(c, X86_FEATURE_ZEN); - /* - * 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) + + /* Fix erratum 1076: CPB feature bit not being set in CPUID. */ + if (!cpu_has(c, X86_FEATURE_CPB)) set_cpu_cap(c, X86_FEATURE_CPB); }