lkml.org 
[lkml]   [2014]   [Jan]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: AMD microcode loading broken on 32 bit
On 01/28/2014 04:30 PM, Borislav Petkov wrote:
> On Tue, Jan 28, 2014 at 04:05:20PM -0500, Boris Ostrovsky wrote:
>> Yes. This was a bug in our build environment. It is fixed now but I
>> put this bug back when I was testing your patch.
> Right, that was the deal. Oh well, we'd need to verify the container
> too, I guess:

I'll give it a spin. Apparently the problem is currently in
install_equiv_cpu_table()
when we are trying to index into buf and buf (which is container)
doesn't appear
to be there.

Are you sure that

container = (u8 *)(__va((u32)relocated_ramdisk) +
((u32)container -
boot_params.hdr.ramdisk_image));

in save_microcode_in_initrd_amd() always results in a valid pointer? It
is non-NULL but it
points to address that looks to be not mapped.

-boris

>
> ---
> diff --git a/arch/x86/kernel/cpu/microcode/amd_early.c b/arch/x86/kernel/cpu/microcode/amd_early.c
> index 8384c0fa206f..c568b6c9af95 100644
> --- a/arch/x86/kernel/cpu/microcode/amd_early.c
> +++ b/arch/x86/kernel/cpu/microcode/amd_early.c
> @@ -37,10 +37,12 @@ static __initdata char ucode_path[] = "kernel/x86/microcode/AuthenticAMD.bin";
>
> static struct cpio_data __init find_ucode_in_initrd(void)
> {
> + struct cpio_data ret;
> long offset = 0;
> char *path;
> void *start;
> size_t size;
> + u32 *hdr;
>
> #ifdef CONFIG_X86_32
> struct boot_params *p;
> @@ -59,7 +61,18 @@ static struct cpio_data __init find_ucode_in_initrd(void)
> size = boot_params.hdr.ramdisk_size;
> #endif
>
> - return find_cpio_data(path, start, size, &offset);
> + ret = find_cpio_data(path, start, size, &offset);
> +
> + /* Verify we didn't get some garbage from the initrd. */
> + hdr = (u32 *)ret.data;
> +
> + if (hdr[0] != UCODE_MAGIC ||
> + hdr[1] != UCODE_EQUIV_CPU_TABLE_TYPE ||
> + hdr[2] == 0) {
> + ret.data = NULL;
> + ret.size = 0;
> + }
> + return ret;
> }
>
> static size_t compute_container_size(u8 *data, u32 total_size)
> @@ -359,7 +372,7 @@ int __init save_microcode_in_initrd_amd(void)
> pr_info("microcode: updated early to new patch_level=0x%08x\n",
> ucode_new_rev);
>
> - if (!container)
> + if (!container || !ucode_cpio.data)
> return -EINVAL;
>
> eax = cpuid_eax(0x00000001);
> --
>



\
 
 \ /
  Last update: 2014-01-28 23:01    [W:0.208 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site