Re: [PATCH] x86/microcode: Disable builtin microcode loading on 32-bit for now

[Shevchenko, Andriy]

On Thu, 2015-06-04 at 11:21 +0200, Borislav Petkov wrote:
> Ok, here's an actual patch. I'm very sorry for the confusion and big
> thanks guys for catching it on time, before it hits the merge window!
> 
> Much appreciated. :-D

Tested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

Thanks!

> ---
> From: Borislav Petkov <bp@xxxxxxx>
> Date: Thu, 4 Jun 2015 09:52:37 +0200
> Subject: [PATCH] x86/microcode: Disable builtin microcode loading on 32-bit for now
> 
> Andy Shevchenko reported machine freezes when booting latest tip on
> x32 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 only on 32-bit for now.
> 
> Reported-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Cc: <x86@xxxxxxxxxx>
> Link: http://lkml.kernel.org/r/1433257003-159485-1-git-send-email-andriy.shevchenko@xxxxxxxxxxxxxxx
> Signed-off-by: 
> ---
>  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";
> -- 
> 2.3.5
> 
> 


-- 
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Intel Finland Oy
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