New Zhaoxin family 7 CPUs are not affected by SPECTRE_V2. So create
a separate cpu_vuln_whitelist flag bit NO_SPECTRE_V2 and add these
CPUs to the cpu vulnerability whitelist.

Signed-off-by: Tony W Wang-oc <TonyWWang-oc@xxxxxxxxxxx>
---
arch/x86/kernel/cpu/common.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 2e4d902..6048bd3 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1023,6 +1023,7 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
#define MSBDS_ONLY BIT(5)
#define NO_SWAPGS BIT(6)
#define NO_ITLB_MULTIHIT BIT(7)
+#define NO_SPECTRE_V2 BIT(8)

#define VULNWL(_vendor, _family, _model, _whitelist) \
{ X86_VENDOR_##_vendor, _family, _model, X86_FEATURE_ANY, _whitelist }
@@ -1084,6 +1085,10 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
/* FAMILY_ANY must be last, otherwise 0x0f - 0x12 matches won't work */
VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
VULNWL_HYGON(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
+
+ /* Zhaoxin Family 7 */
+ VULNWL(CENTAUR, 7, X86_MODEL_ANY, NO_SPECTRE_V2),
+ VULNWL(ZHAOXIN, 7, X86_MODEL_ANY, NO_SPECTRE_V2),
{}
};

@@ -1116,7 +1121,9 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
return;

setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
- setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
+
+ if (!cpu_matches(NO_SPECTRE_V2))
+ setup_force_cpu_bug(X86_BUG_SPECTRE_V2);

if (!cpu_matches(NO_SSB) && !(ia32_cap & ARCH_CAP_SSB_NO) &&
!cpu_has(c, X86_FEATURE_AMD_SSB_NO))
--
2.7.4

 

자오신의 신형 7000번대 프로세서들은 SWAPGS에 영향을 받지 않고, 당연히 소프트웨어 대책도 필요가 없다고 합니다.

스펙터 패치에서도 스펙터 V2에 면역이 있다고 나왔다고 하는군요.