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authorTyler Hicks <tyhicks@canonical.com>2019-11-04 12:22:02 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-11-12 19:19:04 +0100
commitfa8617fddad51c42f66e56cd14382ee0e9f9782e (patch)
treef6150df16ae8256cc1beeca34427b2f4f58a6486 /kernel
parent402c32059af1a308ff9eab0fb3666bb8a6e77c67 (diff)
cpu/speculation: Uninline and export CPU mitigations helpers
commit 731dc9df975a5da21237a18c3384f811a7a41cc6 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpu.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index d768e15bef83..96f970d77339 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2301,7 +2301,18 @@ 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)
{
@@ -2318,3 +2329,17 @@ 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);