[tip:x86/cpu] x86/bugs: Add Hygon Dhyana to the respective mitigation machinery

[tip-bot for Pu Wen]

Commit-ID:  1a576b23d63794f39a247fb31056eecccbf9a287
Gitweb:     https://git.kernel.org/tip/1a576b23d63794f39a247fb31056eecccbf9a287
Author:     Pu Wen <puwen@xxxxxxxx>
AuthorDate: Sun, 23 Sep 2018 17:35:50 +0800
Committer:  Borislav Petkov <bp@xxxxxxx>
CommitDate: Thu, 27 Sep 2018 18:28:59 +0200

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@xxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: tglx@xxxxxxxxxxxxx
Cc: mingo@xxxxxxxxxx
Cc: hpa@xxxxxxxxx
Cc: x86@xxxxxxxxxx
Cc: thomas.lendacky@xxxxxxx
Link: https://lkml.kernel.org/r/0861d39c8a103fc0deca15bafbc85d403666d9ef.1537533369.git.puwen@xxxxxxxx
---
 arch/x86/kernel/cpu/bugs.c   | 4 +++-
 arch/x86/kernel/cpu/common.c | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 40bdaea97fe7..b810cc239375 100644
--- 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 658c85d16a9b..d14c879ba7ba 100644
--- 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 },
 	{}
 };