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Commit 75a1ba5b authored by Borislav Petkov's avatar Borislav Petkov Committed by H. Peter Anvin
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x86, microcode, AMD: Unify valid container checks 



For additional coverage, BorisO and friends unknowlingly did swap AMD
microcode with Intel microcode blobs in order to see what happens. What
did happen on 32-bit was

[    5.722656] BUG: unable to handle kernel paging request at be3a6008
[    5.722693] IP: [<c106d6b4>] load_microcode_amd+0x24/0x3f0
[    5.722716] *pdpt = 0000000000000000 *pde = 0000000000000000

because there was a valid initrd there but without valid microcode in it
and the container check happened *after* the relocated ramdisk handling
on 32-bit, which was clearly wrong.

While at it, take care of the ramdisk relocation on both 32- and 64-bit
as it is done on both. Also, comment what we're doing because this code
is a bit tricky.

Reported-and-tested-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1391460104-7261-1-git-send-email-bp@alien8.de


Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 6583327c

arch/x86/kernel/cpu/microcode/amd_early.c

+29 −14
Original line number Diff line number Diff line
@@ -285,6 +285,15 @@ static void __init collect_cpu_sig_on_bsp(void *arg) 


	uci->cpu_sig.sig = cpuid_eax(0x00000001);

}



static void __init get_bsp_sig(void)

{

	unsigned int bsp = boot_cpu_data.cpu_index;

	struct ucode_cpu_info *uci = ucode_cpu_info + bsp;



	if (!uci->cpu_sig.sig)

		smp_call_function_single(bsp, collect_cpu_sig_on_bsp, NULL, 1);

}

#else

void load_ucode_amd_ap(void)

{
@@ -337,31 +346,37 @@ void load_ucode_amd_ap(void) 


int __init save_microcode_in_initrd_amd(void)

{

	unsigned long cont;

	enum ucode_state ret;

	u32 eax;



#ifdef CONFIG_X86_32

	unsigned int bsp = boot_cpu_data.cpu_index;

	struct ucode_cpu_info *uci = ucode_cpu_info + bsp;



	if (!uci->cpu_sig.sig)

		smp_call_function_single(bsp, collect_cpu_sig_on_bsp, NULL, 1);

	if (!container)

		return -EINVAL;



#ifdef CONFIG_X86_32

	get_bsp_sig();

	cont = (unsigned long)container;

#else

	/*

	 * Take into account the fact that the ramdisk might get relocated

	 * and therefore we need to recompute the container's position in

	 * virtual memory space.

	 * We need the physical address of the container for both bitness since

	 * boot_params.hdr.ramdisk_image is a physical address.

	 */

	container = (u8 *)(__va((u32)relocated_ramdisk) +

			   ((u32)container - boot_params.hdr.ramdisk_image));

	cont = __pa(container);

#endif



	/*

	 * Take into account the fact that the ramdisk might get relocated and

	 * therefore we need to recompute the container's position in virtual

	 * memory space.

	 */

	if (relocated_ramdisk)

		container = (u8 *)(__va(relocated_ramdisk) +

			     (cont - boot_params.hdr.ramdisk_image));



	if (ucode_new_rev)

		pr_info("microcode: updated early to new patch_level=0x%08x\n",

			ucode_new_rev);



	if (!container)

		return -EINVAL;



	eax   = cpuid_eax(0x00000001);

	eax   = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff);