summaryrefslogtreecommitdiffstats
path: root/arch/arm/kernel/spectre.c
diff options
context:
space:
mode:
authorRussell King (Oracle) <rmk+kernel@armlinux.org.uk>2022-02-11 17:45:54 +0100
committerRussell King (Oracle) <rmk+kernel@armlinux.org.uk>2022-03-05 11:41:22 +0100
commit9dd78194a3722fa6712192cdd4f7032d45112a9a (patch)
tree5ee76e8cebc54c104407856e61f83d47c9bf52ee /arch/arm/kernel/spectre.c
parentLinux 5.16 (diff)
downloadlinux-9dd78194a3722fa6712192cdd4f7032d45112a9a.tar.xz
linux-9dd78194a3722fa6712192cdd4f7032d45112a9a.zip
ARM: report Spectre v2 status through sysfs
As per other architectures, add support for reporting the Spectre vulnerability status via sysfs CPU. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel/spectre.c')
-rw-r--r--arch/arm/kernel/spectre.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/arm/kernel/spectre.c b/arch/arm/kernel/spectre.c
new file mode 100644
index 000000000000..6f6dd1cfd099
--- /dev/null
+++ b/arch/arm/kernel/spectre.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/cpu.h>
+#include <linux/device.h>
+
+#include <asm/spectre.h>
+
+ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "Mitigation: __user pointer sanitization\n");
+}
+
+static unsigned int spectre_v2_state;
+static unsigned int spectre_v2_methods;
+
+void spectre_v2_update_state(unsigned int state, unsigned int method)
+{
+ if (state > spectre_v2_state)
+ spectre_v2_state = state;
+ spectre_v2_methods |= method;
+}
+
+ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ const char *method;
+
+ if (spectre_v2_state == SPECTRE_UNAFFECTED)
+ return sprintf(buf, "%s\n", "Not affected");
+
+ if (spectre_v2_state != SPECTRE_MITIGATED)
+ return sprintf(buf, "%s\n", "Vulnerable");
+
+ switch (spectre_v2_methods) {
+ case SPECTRE_V2_METHOD_BPIALL:
+ method = "Branch predictor hardening";
+ break;
+
+ case SPECTRE_V2_METHOD_ICIALLU:
+ method = "I-cache invalidation";
+ break;
+
+ case SPECTRE_V2_METHOD_SMC:
+ case SPECTRE_V2_METHOD_HVC:
+ method = "Firmware call";
+ break;
+
+ default:
+ method = "Multiple mitigations";
+ break;
+ }
+
+ return sprintf(buf, "Mitigation: %s\n", method);
+}