diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 42 | ||||
| -rw-r--r-- | arch/x86/kernel/static_call.c | 2 |
4 files changed, 35 insertions, 16 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index cf447ee18b3c..d6858533e6e5 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -508,6 +508,7 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) } } +#ifdef CONFIG_RETHUNK /* * Rewrite the compiler generated return thunk tail-calls. * @@ -569,6 +570,10 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end) } } } +#else +void __init_or_module noinline apply_returns(s32 *start, s32 *end) { } +#endif /* CONFIG_RETHUNK */ + #else /* !CONFIG_RETPOLINE || !CONFIG_OBJTOOL */ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { } diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 9cfd11f7ba11..35d5288394cb 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -864,6 +864,7 @@ static void init_amd_bd(struct cpuinfo_x86 *c) void init_spectral_chicken(struct cpuinfo_x86 *c) { +#ifdef CONFIG_CPU_UNRET_ENTRY u64 value; /* @@ -880,6 +881,7 @@ void init_spectral_chicken(struct cpuinfo_x86 *c) wrmsrl_safe(MSR_ZEN2_SPECTRAL_CHICKEN, value); } } +#endif } static void init_amd_zn(struct cpuinfo_x86 *c) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 182f8b2e8a3c..cf08a1b8f3c7 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -842,7 +842,6 @@ static int __init retbleed_parse_cmdline(char *str) early_param("retbleed", retbleed_parse_cmdline); #define RETBLEED_UNTRAIN_MSG "WARNING: BTB untrained return thunk mitigation is only effective on AMD/Hygon!\n" -#define RETBLEED_COMPILER_MSG "WARNING: kernel not compiled with RETPOLINE or -mfunction-return capable compiler; falling back to IBPB!\n" #define RETBLEED_INTEL_MSG "WARNING: Spectre v2 mitigation leaves CPU vulnerable to RETBleed attacks, data leaks possible!\n" static void __init retbleed_select_mitigation(void) @@ -857,18 +856,33 @@ static void __init retbleed_select_mitigation(void) return; case RETBLEED_CMD_UNRET: - retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY)) { + retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + } else { + pr_err("WARNING: kernel not compiled with CPU_UNRET_ENTRY.\n"); + goto do_cmd_auto; + } break; case RETBLEED_CMD_IBPB: - retbleed_mitigation = RETBLEED_MITIGATION_IBPB; + if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) { + retbleed_mitigation = RETBLEED_MITIGATION_IBPB; + } else { + pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n"); + goto do_cmd_auto; + } break; +do_cmd_auto: case RETBLEED_CMD_AUTO: default: if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || - boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) - retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) { + if (IS_ENABLED(CONFIG_CPU_UNRET_ENTRY)) + retbleed_mitigation = RETBLEED_MITIGATION_UNRET; + else if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) + retbleed_mitigation = RETBLEED_MITIGATION_IBPB; + } /* * The Intel mitigation (IBRS or eIBRS) was already selected in @@ -881,14 +895,6 @@ static void __init retbleed_select_mitigation(void) switch (retbleed_mitigation) { case RETBLEED_MITIGATION_UNRET: - - if (!IS_ENABLED(CONFIG_RETPOLINE) || - !IS_ENABLED(CONFIG_CC_HAS_RETURN_THUNK)) { - pr_err(RETBLEED_COMPILER_MSG); - retbleed_mitigation = RETBLEED_MITIGATION_IBPB; - goto retbleed_force_ibpb; - } - setup_force_cpu_cap(X86_FEATURE_RETHUNK); setup_force_cpu_cap(X86_FEATURE_UNRET); @@ -900,7 +906,6 @@ static void __init retbleed_select_mitigation(void) break; case RETBLEED_MITIGATION_IBPB: -retbleed_force_ibpb: setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB); mitigate_smt = true; break; @@ -1271,6 +1276,12 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) return SPECTRE_V2_CMD_AUTO; } + if (cmd == SPECTRE_V2_CMD_IBRS && !IS_ENABLED(CONFIG_CPU_IBRS_ENTRY)) { + 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_IBRS && boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) { pr_err("%s selected but not Intel CPU. Switching to AUTO select\n", mitigation_options[i].option); @@ -1328,7 +1339,8 @@ static void __init spectre_v2_select_mitigation(void) break; } - if (boot_cpu_has_bug(X86_BUG_RETBLEED) && + if (IS_ENABLED(CONFIG_CPU_IBRS_ENTRY) && + boot_cpu_has_bug(X86_BUG_RETBLEED) && retbleed_cmd != RETBLEED_CMD_OFF && boot_cpu_has(X86_FEATURE_IBRS) && boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c index fe21fe778185..be7038a0da4d 100644 --- a/arch/x86/kernel/static_call.c +++ b/arch/x86/kernel/static_call.c @@ -126,7 +126,7 @@ void arch_static_call_transform(void *site, void *tramp, void *func, bool tail) } EXPORT_SYMBOL_GPL(arch_static_call_transform); -#ifdef CONFIG_RETPOLINE +#ifdef CONFIG_RETHUNK /* * This is called by apply_returns() to fix up static call trampolines, * specifically ARCH_DEFINE_STATIC_CALL_NULL_TRAMP which is recorded as |