/*
* AMD specific MSR info for Speculative Store Bypass control.
- * x86_amd_ls_cfg_rds_mask is initialized in identify_boot_cpu().
+ * x86_amd_ls_cfg_ssbd_mask is initialized in identify_boot_cpu().
*/
u64 __ro_after_init x86_amd_ls_cfg_base;
-u64 __ro_after_init x86_amd_ls_cfg_rds_mask;
+u64 __ro_after_init x86_amd_ls_cfg_ssbd_mask;
void __init check_bugs(void)
{
u64 msrval = x86_spec_ctrl_base;
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
- msrval |= rds_tif_to_spec_ctrl(current_thread_info()->flags);
+ msrval |= ssbd_tif_to_spec_ctrl(current_thread_info()->flags);
return msrval;
}
EXPORT_SYMBOL_GPL(x86_spec_ctrl_get_default);
return;
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
- host |= rds_tif_to_spec_ctrl(current_thread_info()->flags);
+ host |= ssbd_tif_to_spec_ctrl(current_thread_info()->flags);
if (host != guest_spec_ctrl)
wrmsrl(MSR_IA32_SPEC_CTRL, guest_spec_ctrl);
return;
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
- host |= rds_tif_to_spec_ctrl(current_thread_info()->flags);
+ host |= ssbd_tif_to_spec_ctrl(current_thread_info()->flags);
if (host != guest_spec_ctrl)
wrmsrl(MSR_IA32_SPEC_CTRL, host);
}
EXPORT_SYMBOL_GPL(x86_spec_ctrl_restore_host);
-static void x86_amd_rds_enable(void)
+static void x86_amd_ssb_disable(void)
{
- u64 msrval = x86_amd_ls_cfg_base | x86_amd_ls_cfg_rds_mask;
+ u64 msrval = x86_amd_ls_cfg_base | x86_amd_ls_cfg_ssbd_mask;
- if (boot_cpu_has(X86_FEATURE_AMD_RDS))
+ if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
wrmsrl(MSR_AMD64_LS_CFG, msrval);
}
SPEC_STORE_BYPASS_CMD_AUTO,
SPEC_STORE_BYPASS_CMD_ON,
SPEC_STORE_BYPASS_CMD_PRCTL,
+ SPEC_STORE_BYPASS_CMD_SECCOMP,
};
static const char *ssb_strings[] = {
[SPEC_STORE_BYPASS_NONE] = "Vulnerable",
[SPEC_STORE_BYPASS_DISABLE] = "Mitigation: Speculative Store Bypass disabled",
- [SPEC_STORE_BYPASS_PRCTL] = "Mitigation: Speculative Store Bypass disabled via prctl"
+ [SPEC_STORE_BYPASS_PRCTL] = "Mitigation: Speculative Store Bypass disabled via prctl",
+ [SPEC_STORE_BYPASS_SECCOMP] = "Mitigation: Speculative Store Bypass disabled via prctl and seccomp",
};
static const struct {
const char *option;
enum ssb_mitigation_cmd cmd;
} ssb_mitigation_options[] = {
- { "auto", SPEC_STORE_BYPASS_CMD_AUTO }, /* Platform decides */
- { "on", SPEC_STORE_BYPASS_CMD_ON }, /* Disable Speculative Store Bypass */
- { "off", SPEC_STORE_BYPASS_CMD_NONE }, /* Don't touch Speculative Store Bypass */
- { "prctl", SPEC_STORE_BYPASS_CMD_PRCTL }, /* Disable Speculative Store Bypass via prctl */
+ { "auto", SPEC_STORE_BYPASS_CMD_AUTO }, /* Platform decides */
+ { "on", SPEC_STORE_BYPASS_CMD_ON }, /* Disable Speculative Store Bypass */
+ { "off", SPEC_STORE_BYPASS_CMD_NONE }, /* Don't touch Speculative Store Bypass */
+ { "prctl", SPEC_STORE_BYPASS_CMD_PRCTL }, /* Disable Speculative Store Bypass via prctl */
+ { "seccomp", SPEC_STORE_BYPASS_CMD_SECCOMP }, /* Disable Speculative Store Bypass via prctl and seccomp */
};
static enum ssb_mitigation_cmd __init ssb_parse_cmdline(void)
return cmd;
}
-static enum ssb_mitigation_cmd __init __ssb_select_mitigation(void)
+static enum ssb_mitigation __init __ssb_select_mitigation(void)
{
enum ssb_mitigation mode = SPEC_STORE_BYPASS_NONE;
enum ssb_mitigation_cmd cmd;
- if (!boot_cpu_has(X86_FEATURE_RDS))
+ if (!boot_cpu_has(X86_FEATURE_SSBD))
return mode;
cmd = ssb_parse_cmdline();
switch (cmd) {
case SPEC_STORE_BYPASS_CMD_AUTO:
- /* Choose prctl as the default mode */
- mode = SPEC_STORE_BYPASS_PRCTL;
+ case SPEC_STORE_BYPASS_CMD_SECCOMP:
+ /*
+ * Choose prctl+seccomp as the default mode if seccomp is
+ * enabled.
+ */
+ if (IS_ENABLED(CONFIG_SECCOMP))
+ mode = SPEC_STORE_BYPASS_SECCOMP;
+ else
+ mode = SPEC_STORE_BYPASS_PRCTL;
break;
case SPEC_STORE_BYPASS_CMD_ON:
mode = SPEC_STORE_BYPASS_DISABLE;
/*
* We have three CPU feature flags that are in play here:
* - X86_BUG_SPEC_STORE_BYPASS - CPU is susceptible.
- * - X86_FEATURE_RDS - CPU is able to turn off speculative store bypass
+ * - X86_FEATURE_SSBD - CPU is able to turn off speculative store bypass
* - X86_FEATURE_SPEC_STORE_BYPASS_DISABLE - engage the mitigation
*/
if (mode == SPEC_STORE_BYPASS_DISABLE) {
*/
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_INTEL:
- x86_spec_ctrl_base |= SPEC_CTRL_RDS;
- x86_spec_ctrl_mask &= ~SPEC_CTRL_RDS;
- x86_spec_ctrl_set(SPEC_CTRL_RDS);
+ x86_spec_ctrl_base |= SPEC_CTRL_SSBD;
+ x86_spec_ctrl_mask &= ~SPEC_CTRL_SSBD;
+ x86_spec_ctrl_set(SPEC_CTRL_SSBD);
break;
case X86_VENDOR_AMD:
- x86_amd_rds_enable();
+ x86_amd_ssb_disable();
break;
}
}
}
#undef pr_fmt
+#define pr_fmt(fmt) "Speculation prctl: " fmt
static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl)
{
- bool rds = !!test_tsk_thread_flag(task, TIF_RDS);
+ bool update;
- if (ssb_mode != SPEC_STORE_BYPASS_PRCTL)
+ if (ssb_mode != SPEC_STORE_BYPASS_PRCTL &&
+ ssb_mode != SPEC_STORE_BYPASS_SECCOMP)
return -ENXIO;
- if (ctrl == PR_SPEC_ENABLE)
- clear_tsk_thread_flag(task, TIF_RDS);
- else
- set_tsk_thread_flag(task, TIF_RDS);
+ switch (ctrl) {
+ case PR_SPEC_ENABLE:
+ /* If speculation is force disabled, enable is not allowed */
+ if (task_spec_ssb_force_disable(task))
+ return -EPERM;
+ task_clear_spec_ssb_disable(task);
+ update = test_and_clear_tsk_thread_flag(task, TIF_SSBD);
+ break;
+ case PR_SPEC_DISABLE:
+ task_set_spec_ssb_disable(task);
+ update = !test_and_set_tsk_thread_flag(task, TIF_SSBD);
+ break;
+ case PR_SPEC_FORCE_DISABLE:
+ task_set_spec_ssb_disable(task);
+ task_set_spec_ssb_force_disable(task);
+ update = !test_and_set_tsk_thread_flag(task, TIF_SSBD);
+ break;
+ default:
+ return -ERANGE;
+ }
/*
* If being set on non-current task, delay setting the CPU
* mitigation until it is next scheduled.
*/
- if (task == current && rds != !!test_tsk_thread_flag(task, TIF_RDS))
+ if (task == current && update)
speculative_store_bypass_update();
return 0;
}
+int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which,
+ unsigned long ctrl)
+{
+ switch (which) {
+ case PR_SPEC_STORE_BYPASS:
+ return ssb_prctl_set(task, ctrl);
+ default:
+ return -ENODEV;
+ }
+}
+
+#ifdef CONFIG_SECCOMP
+void arch_seccomp_spec_mitigate(struct task_struct *task)
+{
+ if (ssb_mode == SPEC_STORE_BYPASS_SECCOMP)
+ ssb_prctl_set(task, PR_SPEC_FORCE_DISABLE);
+}
+#endif
+
static int ssb_prctl_get(struct task_struct *task)
{
switch (ssb_mode) {
case SPEC_STORE_BYPASS_DISABLE:
return PR_SPEC_DISABLE;
+ case SPEC_STORE_BYPASS_SECCOMP:
case SPEC_STORE_BYPASS_PRCTL:
- if (test_tsk_thread_flag(task, TIF_RDS))
+ if (task_spec_ssb_force_disable(task))
+ return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE;
+ if (task_spec_ssb_disable(task))
return PR_SPEC_PRCTL | PR_SPEC_DISABLE;
return PR_SPEC_PRCTL | PR_SPEC_ENABLE;
default:
}
}
-int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which,
- unsigned long ctrl)
-{
- if (ctrl != PR_SPEC_ENABLE && ctrl != PR_SPEC_DISABLE)
- return -ERANGE;
-
- switch (which) {
- case PR_SPEC_STORE_BYPASS:
- return ssb_prctl_set(task, ctrl);
- default:
- return -ENODEV;
- }
-}
-
int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which)
{
switch (which) {
x86_spec_ctrl_set(x86_spec_ctrl_base & ~x86_spec_ctrl_mask);
if (ssb_mode == SPEC_STORE_BYPASS_DISABLE)
- x86_amd_rds_enable();
+ x86_amd_ssb_disable();
}
#ifdef CONFIG_SYSFS
projects / mirror_ubuntu-artful-kernel.git / blobdiff