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Commit 2eff73c0 authored by Borislav Petkov's avatar Borislav Petkov Committed by Ingo Molnar
Browse files

x86/microcode/amd: Extract current patch level read to a function 

Pave the way for checking the current patch level of the
microcode in a core. We want to be able to do stuff depending on
the patch level - in this case decide whether to update or not.
But that will be added in a later patch.

Drop unused local var uci assignment, while at it.

Integrate a fix for 32-bit and CONFIG_PARAVIRT from Takashi Iwai:

 Use native_rdmsr() in check_current_patch_level() because with
 CONFIG_PARAVIRT enabled and on 32-bit, where we run before
 paging has been enabled, we cannot deref pv_info yet. Or we
 could, but we'd need to access its physical address. This way of
 fixing it is simpler. See:

   https://bugzilla.suse.com/show_bug.cgi?id=943179

 for the background.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Takashi Iwai <tiwai@suse.com>:
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1444641762-9437-6-git-send-email-bp@alien8.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent fa20a2ed

arch/x86/include/asm/microcode_amd.h

+1 −0
Original line number Diff line number Diff line
@@ -76,4 +76,5 @@ static inline int __init save_microcode_in_initrd_amd(void) { return -EINVAL; } 
void reload_ucode_amd(void) {}

#endif



extern bool check_current_patch_level(u32 *rev);

#endif /* _ASM_X86_MICROCODE_AMD_H */

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

+22 −2
Original line number Diff line number Diff line
@@ -177,6 +177,25 @@ static unsigned int verify_patch_size(u8 family, u32 patch_size, 
	return patch_size;

}



/*

 * Check the current patch level on this CPU.

 *

 * @rev: Use it to return the patch level. It is set to 0 in the case of

 * error.

 *

 * Returns:

 *  - true: if update should stop

 *  - false: otherwise

 */

bool check_current_patch_level(u32 *rev)

{

	u32 dummy;



	native_rdmsr(MSR_AMD64_PATCH_LEVEL, *rev, dummy);



	return false;

}



int __apply_microcode_amd(struct microcode_amd *mc_amd)

{

	u32 rev, dummy;
@@ -197,7 +216,7 @@ int apply_microcode_amd(int cpu) 
	struct microcode_amd *mc_amd;

	struct ucode_cpu_info *uci;

	struct ucode_patch *p;

	u32 rev, dummy;

	u32 rev;



	BUG_ON(raw_smp_processor_id() != cpu);
@@ -210,7 +229,8 @@ int apply_microcode_amd(int cpu) 
	mc_amd  = p->data;

	uci->mc = p->data;



	rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);

	if (check_current_patch_level(&rev))

		return -1;



	/* need to apply patch? */

	if (rev >= mc_amd->hdr.patch_id) {

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

+7 −10
Original line number Diff line number Diff line
@@ -196,9 +196,8 @@ static void apply_ucode_in_initrd(void *ucode, size_t size, bool save_patch) 
		return;

	}



	/* find ucode and update if needed */



	native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, eax);

	if (check_current_patch_level(&rev))

		return;



	while (left > 0) {

		struct microcode_amd *mc;
@@ -319,7 +318,6 @@ static void __init get_bsp_sig(void) 
void load_ucode_amd_ap(void)

{

	unsigned int cpu = smp_processor_id();

	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	struct equiv_cpu_entry *eq;

	struct microcode_amd *mc;

	u32 rev, eax;
@@ -332,10 +330,8 @@ void load_ucode_amd_ap(void) 
	if (!container)

		return;



	rdmsr(MSR_AMD64_PATCH_LEVEL, rev, eax);



	uci->cpu_sig.rev = rev;

	uci->cpu_sig.sig = eax;

	if (check_current_patch_level(&rev))

		return;



	eax = cpuid_eax(0x00000001);

	eq  = (struct equiv_cpu_entry *)(container + CONTAINER_HDR_SZ);
@@ -424,9 +420,10 @@ int __init save_microcode_in_initrd_amd(void) 
void reload_ucode_amd(void)

{

	struct microcode_amd *mc;

	u32 rev, eax;

	u32 rev;



	rdmsr(MSR_AMD64_PATCH_LEVEL, rev, eax);

	if (check_current_patch_level(&rev))

		return;



	mc = (struct microcode_amd *)amd_ucode_patch;