From ee38a90709084b1c91279cde8f783e90f85285a1 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 4 Jun 2015 18:55:27 +0200 Subject: [PATCH] x86/microcode: Disable builtin microcode loading on 32-bit for now Andy Shevchenko reported machine freezes when booting latest tip on 32-bit setups. Problem is, the builtin microcode handling cannot really work that early, when we haven't even enabled paging. A proper fix would involve handling that case specially as every other early 32-bit boot case in the microcode loader and would require much more involved changes for which it is too late now, more than a week before the upcoming merge window. So, disable the builtin microcode loading on 32-bit for now. Reported-and-tested-by: Andy Shevchenko Signed-off-by: Borislav Petkov Cc: Andrew Morton Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1433436928-31903-20-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/microcode/amd_early.c | 4 ++++ arch/x86/kernel/cpu/microcode/intel_early.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/arch/x86/kernel/cpu/microcode/amd_early.c b/arch/x86/kernel/cpu/microcode/amd_early.c index 9208a36d0f03..9243cd839829 100644 --- a/arch/x86/kernel/cpu/microcode/amd_early.c +++ b/arch/x86/kernel/cpu/microcode/amd_early.c @@ -230,6 +230,7 @@ static void apply_ucode_in_initrd(void *ucode, size_t size, bool save_patch) static bool __init load_builtin_amd_microcode(struct cpio_data *cp, int family) { +#ifdef CONFIG_X86_64 char fw_name[36] = "amd-ucode/microcode_amd.bin"; if (family >= 0x15) @@ -237,6 +238,9 @@ static bool __init load_builtin_amd_microcode(struct cpio_data *cp, int family) "amd-ucode/microcode_amd_fam%.2xh.bin", family); return get_builtin_firmware(cp, fw_name); +#else + return false; +#endif } void __init load_ucode_amd_bsp(int family) diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c index 10dff3f3f686..b4858d892592 100644 --- a/arch/x86/kernel/cpu/microcode/intel_early.c +++ b/arch/x86/kernel/cpu/microcode/intel_early.c @@ -523,6 +523,7 @@ EXPORT_SYMBOL_GPL(save_mc_for_early); static bool __init load_builtin_intel_microcode(struct cpio_data *cp) { +#ifdef CONFIG_X86_64 u32 eax = 0x00000001, ebx, ecx = 0, edx; int family, model, stepping; char name[30]; @@ -536,6 +537,9 @@ static bool __init load_builtin_intel_microcode(struct cpio_data *cp) sprintf(name, "intel-ucode/%02x-%02x-%02x", family, model, stepping); return get_builtin_firmware(cp, name); +#else + return false; +#endif } static __initdata char ucode_name[] = "kernel/x86/microcode/GenuineIntel.bin";