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

commit 1a576b23d63794f39a247fb31056eecccbf9a287 upstream.

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.

 [ puwen: Convert Hygon Meltdown mitigation machinery to fit new code. ]
Signed-off-by: NPu Wen <puwen@hygon.cn>
Signed-off-by: NBorislav 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.cnAcked-by: NCaspar Zhang <caspar@linux.alibaba.com>

arch/x86/kernel/cpu/bugs.c

@@ -735,6 +735,7 @@ 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;
@@ -791,7 +792,8 @@ 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");

arch/x86/kernel/cpu/common.c

@@ -970,6 +970,9 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
 #define VULNWL_AMD(family, whitelist)		\
 	VULNWL(AMD, family, X86_MODEL_ANY, whitelist)
 
+#define VULNWL_HYGON(family, whitelist)		\
+	VULNWL(HYGON, family, X86_MODEL_ANY, whitelist)
+
 static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
 	VULNWL(ANY,	4, X86_MODEL_ANY,	NO_SPECULATION),
 	VULNWL(CENTAUR,	5, X86_MODEL_ANY,	NO_SPECULATION),
@@ -1016,6 +1019,7 @@ 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),
 	{}
 };