x86/bugs: Add Hygon Dhyana to the respective mitigation machinery

The Hygon Dhyana CPU has the same speculative execution as AMD family
17h, so share AMD spectre mitigation code with Hygon Dhyana.

Also Hygon Dhyana is not affected by meltdown, so add exception for it.

Signed-off-by: Pu Wen <puwen@hygon.cn>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: x86@kernel.org
Cc: thomas.lendacky@amd.com
Link: https://lkml.kernel.org/r/0861d39c8a103fc0deca15bafbc85d403666d9ef.1537533369.git.puwen@hygon.cn

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 40bdaea97fe7cac25f2b04bc239fdc520d68f09e..b810cc23937515430c8b24f51a4831051039e383 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -312,6 +312,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
        }
 
        if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD &&
+           boot_cpu_data.x86_vendor != X86_VENDOR_HYGON &&
            boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
                pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
                return SPECTRE_V2_CMD_AUTO;
@@ -371,7 +372,8 @@ static void __init spectre_v2_select_mitigation(void)
        return;
 
 retpoline_auto:
-       if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
+       if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+           boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
        retpoline_amd:
                if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) {
                        pr_err("Spectre mitigation: LFENCE not serializing, switching to generic retpoline\n");

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 658c85d16a9b8404c7e68f11750d429b667485a6..d14c879ba7ba3c4d874222eb2f279856a64e7b1f 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -963,6 +963,7 @@ static const __initconst struct x86_cpu_id cpu_no_speculation[] = {
 
 static const __initconst struct x86_cpu_id cpu_no_meltdown[] = {
        { X86_VENDOR_AMD },
+       { X86_VENDOR_HYGON },
        {}
 };