From 731dc9df975a5da21237a18c3384f811a7a41cc6 Mon Sep 17 00:00:00 2001
From: Tyler Hicks <tyhicks@canonical.com>
Date: Mon, 4 Nov 2019 12:22:02 +0100
Subject: [PATCH] cpu/speculation: Uninline and export CPU mitigations helpers
A kernel module may need to check the value of the "mitigations=" kernel
command line parameter as part of its setup when the module needs
to perform software mitigations for a CPU flaw.
Uninline and export the helper functions surrounding the cpu_mitigations
enum to allow for their usage from a module.
Lastly, privatize the enum and cpu_mitigations variable since the value of
cpu_mitigations can be checked with the exported helper functions.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/cpu.h | 25 ++-----------------------
kernel/cpu.c | 27 ++++++++++++++++++++++++++-
2 files changed, 28 insertions(+), 24 deletions(-)
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 2a093434e975..bc6c879bd110 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -218,28 +218,7 @@ static inline int cpuhp_smt_enable(void) { return 0; }
static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; }
#endif
-/*
- * These are used for a global "mitigations=" cmdline option for toggling
- * optional CPU mitigations.
- */
-enum cpu_mitigations {
- CPU_MITIGATIONS_OFF,
- CPU_MITIGATIONS_AUTO,
- CPU_MITIGATIONS_AUTO_NOSMT,
-};
-
-extern enum cpu_mitigations cpu_mitigations;
-
-/* mitigations=off */
-static inline bool cpu_mitigations_off(void)
-{
- return cpu_mitigations == CPU_MITIGATIONS_OFF;
-}
-
-/* mitigations=auto,nosmt */
-static inline bool cpu_mitigations_auto_nosmt(void)
-{
- return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT;
-}
+extern bool cpu_mitigations_off(void);
+extern bool cpu_mitigations_auto_nosmt(void);
#endif /* _LINUX_CPU_H_ */
diff --git a/kernel/cpu.c b/kernel/cpu.c
index fc28e17940e0..e2cad3ee2ead 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2373,7 +2373,18 @@ void __init boot_cpu_hotplug_init(void)
this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
}
-enum cpu_mitigations cpu_mitigations __ro_after_init = CPU_MITIGATIONS_AUTO;
+/*
+ * These are used for a global "mitigations=" cmdline option for toggling
+ * optional CPU mitigations.
+ */
+enum cpu_mitigations {
+ CPU_MITIGATIONS_OFF,
+ CPU_MITIGATIONS_AUTO,
+ CPU_MITIGATIONS_AUTO_NOSMT,
+};
+
+static enum cpu_mitigations cpu_mitigations __ro_after_init =
+ CPU_MITIGATIONS_AUTO;
static int __init mitigations_parse_cmdline(char *arg)
{
@@ -2390,3 +2401,17 @@ static int __init mitigations_parse_cmdline(char *arg)
return 0;
}
early_param("mitigations", mitigations_parse_cmdline);
+
+/* mitigations=off */
+bool cpu_mitigations_off(void)
+{
+ return cpu_mitigations == CPU_MITIGATIONS_OFF;
+}
+EXPORT_SYMBOL_GPL(cpu_mitigations_off);
+
+/* mitigations=auto,nosmt */
+bool cpu_mitigations_auto_nosmt(void)
+{
+ return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT;
+}
+EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt);