[PATCH v3 09/17] x86/bugs: add lfence mitigation to spectre v2 and no meltdown for Hygon
From: Pu Wen <puwen@hygon.cn>
Date: 2018-08-11 13:28:37
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 hardware vulnerabilities · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Peter Zijlstra, Josh Poimboeuf
To share codes between AMD and Hygon to mitigate Spectre V2 Retpoline vulnerability, rename macros SPECTRE_V2_RETPOLINE_MINIMAL_AMD to SPECTRE_V2_RETPOLINE_MINIMAL_LFENCE, and SPECTRE_V2_CMD_RETPOLINE_AMD to SPECTRE_V2_CMD_RETPOLINE_LFENCE. As Hygon processors are not affected by meltdown vulnerability as AMD's, so add exception in array cpu_no_meltdown[] for Hygon. Signed-off-by: Pu Wen <puwen@hygon.cn> --- arch/x86/include/asm/nospec-branch.h | 4 ++-- arch/x86/kernel/cpu/bugs.c | 28 +++++++++++++++------------- arch/x86/kernel/cpu/common.c | 1 + 3 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index f6f6c63..aad6b9c 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h@@ -211,9 +211,9 @@ enum spectre_v2_mitigation { SPECTRE_V2_NONE, SPECTRE_V2_RETPOLINE_MINIMAL, - SPECTRE_V2_RETPOLINE_MINIMAL_AMD, + SPECTRE_V2_RETPOLINE_MINIMAL_LFENCE, SPECTRE_V2_RETPOLINE_GENERIC, - SPECTRE_V2_RETPOLINE_AMD, + SPECTRE_V2_RETPOLINE_LFENCE, SPECTRE_V2_IBRS, };
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 5c0ea39..d477aa1 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c@@ -121,15 +121,15 @@ enum spectre_v2_mitigation_cmd { SPECTRE_V2_CMD_FORCE, SPECTRE_V2_CMD_RETPOLINE, SPECTRE_V2_CMD_RETPOLINE_GENERIC, - SPECTRE_V2_CMD_RETPOLINE_AMD, + SPECTRE_V2_CMD_RETPOLINE_LFENCE, }; static const char *spectre_v2_strings[] = { [SPECTRE_V2_NONE] = "Vulnerable", [SPECTRE_V2_RETPOLINE_MINIMAL] = "Vulnerable: Minimal generic ASM retpoline", - [SPECTRE_V2_RETPOLINE_MINIMAL_AMD] = "Vulnerable: Minimal AMD ASM retpoline", + [SPECTRE_V2_RETPOLINE_MINIMAL_LFENCE] = "Vulnerable: Minimal LFENCE ASM retpoline", [SPECTRE_V2_RETPOLINE_GENERIC] = "Mitigation: Full generic retpoline", - [SPECTRE_V2_RETPOLINE_AMD] = "Mitigation: Full AMD retpoline", + [SPECTRE_V2_RETPOLINE_LFENCE] = "Mitigation: Full LFENCE retpoline", }; #undef pr_fmt
@@ -260,7 +260,7 @@ static const struct { { "off", SPECTRE_V2_CMD_NONE, false }, { "on", SPECTRE_V2_CMD_FORCE, true }, { "retpoline", SPECTRE_V2_CMD_RETPOLINE, false }, - { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_AMD, false }, + { "retpoline,lfence", SPECTRE_V2_CMD_RETPOLINE_LFENCE, false }, { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false }, { "auto", SPECTRE_V2_CMD_AUTO, false }, };
@@ -292,16 +292,17 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) } if ((cmd == SPECTRE_V2_CMD_RETPOLINE || - cmd == SPECTRE_V2_CMD_RETPOLINE_AMD || + cmd == SPECTRE_V2_CMD_RETPOLINE_LFENCE || cmd == SPECTRE_V2_CMD_RETPOLINE_GENERIC) && !IS_ENABLED(CONFIG_RETPOLINE)) { pr_err("%s selected but not compiled in. Switching to AUTO select\n", mitigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } - if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD && + if (cmd == SPECTRE_V2_CMD_RETPOLINE_LFENCE && + 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"); + pr_err("retpoline,lfence selected but CPU is not AMD or Hygon. Switching to AUTO select\n"); return SPECTRE_V2_CMD_AUTO; }
@@ -352,9 +353,9 @@ static void __init spectre_v2_select_mitigation(void) if (IS_ENABLED(CONFIG_RETPOLINE)) goto retpoline_auto; break; - case SPECTRE_V2_CMD_RETPOLINE_AMD: + case SPECTRE_V2_CMD_RETPOLINE_LFENCE: if (IS_ENABLED(CONFIG_RETPOLINE)) - goto retpoline_amd; + goto retpoline_lfence; break; case SPECTRE_V2_CMD_RETPOLINE_GENERIC: if (IS_ENABLED(CONFIG_RETPOLINE))
@@ -369,14 +370,15 @@ static void __init spectre_v2_select_mitigation(void) return; retpoline_auto: - if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { - retpoline_amd: + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) { + retpoline_lfence: if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { pr_err("Spectre mitigation: LFENCE not serializing, switching to generic retpoline\n"); goto retpoline_generic; } - mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_AMD : - SPECTRE_V2_RETPOLINE_MINIMAL_AMD; + mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_LFENCE : + SPECTRE_V2_RETPOLINE_MINIMAL_LFENCE; setup_force_cpu_cap(X86_FEATURE_RETPOLINE_AMD); setup_force_cpu_cap(X86_FEATURE_RETPOLINE); } else {
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index eb4cb3e..06b3168 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c@@ -968,6 +968,7 @@ 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 }, {} };
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2.7.4