From 30ec26da9967d0d785abc24073129a34c3211777 Mon Sep 17 00:00:00 2001 | |
From: Ashok Raj <ashok.raj@intel.com> | |
Date: Wed, 28 Feb 2018 11:28:43 +0100 | |
Subject: x86/microcode: Do not upload microcode if CPUs are offline | |
Avoid loading microcode if any of the CPUs are offline, and issue a | |
warning. Having different microcode revisions on the system at any time | |
is outright dangerous. | |
[ Borislav: Massage changelog. ] | |
Signed-off-by: Ashok Raj <ashok.raj@intel.com> | |
Signed-off-by: Borislav Petkov <bp@suse.de> | |
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> | |
Tested-by: Tom Lendacky <thomas.lendacky@amd.com> | |
Tested-by: Ashok Raj <ashok.raj@intel.com> | |
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> | |
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> | |
Link: http://lkml.kernel.org/r/1519352533-15992-4-git-send-email-ashok.raj@intel.com | |
Link: https://lkml.kernel.org/r/20180228102846.13447-5-bp@alien8.de | |
--- | |
arch/x86/kernel/cpu/microcode/core.c | 18 ++++++++++++++++++ | |
1 file changed, 18 insertions(+) | |
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c | |
index 6337065..fa32cb3 100644 | |
--- a/arch/x86/kernel/cpu/microcode/core.c | |
+++ b/arch/x86/kernel/cpu/microcode/core.c | |
@@ -486,6 +486,16 @@ static void __exit microcode_dev_exit(void) | |
/* fake device for request_firmware */ | |
static struct platform_device *microcode_pdev; | |
+static int check_online_cpus(void) | |
+{ | |
+ if (num_online_cpus() == num_present_cpus()) | |
+ return 0; | |
+ | |
+ pr_err("Not all CPUs online, aborting microcode update.\n"); | |
+ | |
+ return -EINVAL; | |
+} | |
+ | |
static enum ucode_state reload_for_cpu(int cpu) | |
{ | |
struct ucode_cpu_info *uci = ucode_cpu_info + cpu; | |
@@ -519,7 +529,13 @@ static ssize_t reload_store(struct device *dev, | |
return size; | |
get_online_cpus(); | |
+ | |
+ ret = check_online_cpus(); | |
+ if (ret) | |
+ goto put; | |
+ | |
mutex_lock(µcode_mutex); | |
+ | |
for_each_online_cpu(cpu) { | |
tmp_ret = reload_for_cpu(cpu); | |
if (tmp_ret > UCODE_NFOUND) { | |
@@ -538,6 +554,8 @@ static ssize_t reload_store(struct device *dev, | |
microcode_check(); | |
mutex_unlock(µcode_mutex); | |
+ | |
+put: | |
put_online_cpus(); | |
if (!ret) | |
-- | |
cgit v1.1 | |