CPUID Fn8000_0007_EDX[CPB] is wrongly 0 on some newer F17h procssors but their revision guide has not been released.
For example,Tesed on AMD "Ryzen 7 2700U with Radeon Vega Mobile Gfx" and "AMD Ryzen 5 2500U with Radeon Vega Mobile Gfx", their CPUID Fn0000_0001_EAX is 0x00810f10 and should have CPB feature according AMD product specifications, however their Fn8000_0007_EDX is 0x00006599, indicating they don't support CPB feature.
Since whole F17h should support CPB, we set the cap for all of them.
Cc: stable@vger.kernel.org Signed-off-by: Jiaxun Yang jiaxun.yang@flygoat.com --- arch/x86/kernel/cpu/amd.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index eeea634bee0a..37989fa9e620 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -818,12 +818,13 @@ static void init_amd_bd(struct cpuinfo_x86 *c) 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. + * a lot of Family 17h processors and some models are undocumented, since + * whole F17h should support CPB, we set the cap for all of them. */ - if (c->x86_model <= 1 && c->x86_stepping <= 1) - set_cpu_cap(c, X86_FEATURE_CPB); + set_cpu_cap(c, X86_FEATURE_CPB); }
static void init_amd(struct cpuinfo_x86 *c) -- 2.19.1