diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Kconfig | 12 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 9 |
2 files changed, 17 insertions, 4 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 22d324581a60..33e125a28f79 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2716,6 +2716,18 @@ config MITIGATION_SPECTRE_V1 memory access bounds check. See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> +config MITIGATION_SPECTRE_V2 + bool "Mitigate SPECTRE V2 hardware bug" + default y + help + Enable mitigation for Spectre V2 (Branch Target Injection). Spectre + V2 is a class of side channel attacks that takes advantage of + indirect branch predictors inside the processor. In Spectre variant 2 + attacks, the attacker can steer speculative indirect branches in the + victim to gadget code by poisoning the branch target buffer of a CPU + used for predicting indirect branch addresses. + See also <file:Documentation/admin-guide/hw-vuln/spectre.rst> + config MITIGATION_SRBDS bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug" depends on CPU_SUP_INTEL diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 8292a96d376c..45cbc6f994ca 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1452,17 +1452,18 @@ static void __init spec_v2_print_cond(const char *reason, bool secure) static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) { - enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO; + enum spectre_v2_mitigation_cmd cmd; char arg[20]; int ret, i; + cmd = IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V2) ? SPECTRE_V2_CMD_AUTO : SPECTRE_V2_CMD_NONE; if (cmdline_find_option_bool(boot_command_line, "nospectre_v2") || cpu_mitigations_off()) return SPECTRE_V2_CMD_NONE; ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg)); if (ret < 0) - return SPECTRE_V2_CMD_AUTO; + return cmd; for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) { if (!match_option(arg, ret, mitigation_options[i].option)) @@ -1472,8 +1473,8 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) } if (i >= ARRAY_SIZE(mitigation_options)) { - pr_err("unknown option (%s). Switching to AUTO select\n", arg); - return SPECTRE_V2_CMD_AUTO; + pr_err("unknown option (%s). Switching to default mode\n", arg); + return cmd; } if ((cmd == SPECTRE_V2_CMD_RETPOLINE || |