From 84749d83758af6576552046b215b9b7f37f9556b Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sat, 21 Apr 2018 10:19:29 +0200 Subject: x86/microcode/intel: Save microcode patch unconditionally save_mc_for_early() was a no-op on !CONFIG_HOTPLUG_CPU but the generic_load_microcode() path saves the microcode patches it has found into the cache of patches which is used for late loading too. Regardless of whether CPU hotplug is used or not. Make the saving unconditional so that late loading can find the proper patch. Reported-by: Vitezslav Samel Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Vitezslav Samel Tested-by: Ashok Raj Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20180418081140.GA2439@pc11.op.pod.cz Link: https://lkml.kernel.org/r/20180421081930.15741-1-bp@alien8.de --- arch/x86/kernel/cpu/microcode/intel.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 32b8e5724f96..1c2cfa0644aa 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -485,7 +485,6 @@ static void show_saved_mc(void) */ static void save_mc_for_early(u8 *mc, unsigned int size) { -#ifdef CONFIG_HOTPLUG_CPU /* Synchronization during CPU hotplug. */ static DEFINE_MUTEX(x86_cpu_microcode_mutex); @@ -495,7 +494,6 @@ static void save_mc_for_early(u8 *mc, unsigned int size) show_saved_mc(); mutex_unlock(&x86_cpu_microcode_mutex); -#endif } static bool load_builtin_intel_microcode(struct cpio_data *cp) -- cgit v1.3-14-g43fede From 09e182d17e8891dd73baba961a0f5a82e9274c97 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sat, 21 Apr 2018 10:19:30 +0200 Subject: x86/microcode: Do not exit early from __reload_late() Vitezslav reported a case where the "Timeout during microcode update!" panic would hit. After a deeper look, it turned out that his .config had CONFIG_HOTPLUG_CPU disabled which practically made save_mc_for_early() a no-op. When that happened, the discovered microcode patch wasn't saved into the cache and the late loading path wouldn't find any. This, then, lead to early exit from __reload_late() and thus CPUs waiting until the timeout is reached, leading to the panic. In hindsight, that function should have been written so it does not return before the post-synchronization. Oh well, I know better now... Fixes: bb8c13d61a62 ("x86/microcode: Fix CPU synchronization routine") Reported-by: Vitezslav Samel Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Vitezslav Samel Tested-by: Ashok Raj Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20180418081140.GA2439@pc11.op.pod.cz Link: https://lkml.kernel.org/r/20180421081930.15741-2-bp@alien8.de --- arch/x86/kernel/cpu/microcode/core.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 10c4fc2c91f8..77e201301528 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -564,14 +564,12 @@ static int __reload_late(void *info) apply_microcode_local(&err); spin_unlock(&update_lock); + /* siblings return UCODE_OK because their engine got updated already */ if (err > UCODE_NFOUND) { pr_warn("Error reloading microcode on CPU %d\n", cpu); - return -1; - /* siblings return UCODE_OK because their engine got updated already */ + ret = -1; } else if (err == UCODE_UPDATED || err == UCODE_OK) { ret = 1; - } else { - return ret; } /* -- cgit v1.3-14-g43fede