Commit f436f8bb authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: EDAC: MCE: Fix MCE decoding callback logic 



Make decoding of MCEs happen only on AMD hardware by registering a
non-default callback only on CPU families which support it.

While looking at the interaction of decode_mce() with the other MCE
code i also noticed a few other things and made the following
cleanups/fixes:

 - Fixed the mce_decode() weak alias - a weak alias is really not
   good here, it should be a proper callback. A weak alias will be
   overriden if a piece of code is built into the kernel - not
   good, obviously.

 - The patch initializes the callback on AMD family 10h and 11h.

 - Added the more correct fallback printk of:

	No support for human readable MCE decoding on this CPU type.
	Transcribe the message and run it through 'mcelog --ascii' to decode.

   On CPUs that dont have a decoder.

 - Made the surrounding code more readable.

Note that the callback allows us to have a default fallback -
without having to check the CPU versions during the printout
itself. When an EDAC module registers itself, it can install the
decode-print function.

(there's no unregister needed as this is core code.)

version -v2 by Borislav Petkov:

 - add K8 to the set of supported CPUs

 - always build in edac_mce_amd since we use an early_initcall now

 - fix checkpatch warnings

Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
LKML-Reference: <20091001141432.GA11410@aftab>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 24e35800

arch/x86/include/asm/mce.h

+2 −0
Original line number Diff line number Diff line
@@ -133,6 +133,8 @@ static inline void winchip_mcheck_init(struct cpuinfo_x86 *c) {} 
static inline void enable_p5_mce(void) {}

#endif



extern void (*x86_mce_decode_callback)(struct mce *m);



void mce_setup(struct mce *m);

void mce_log(struct mce *m);

DECLARE_PER_CPU(struct sys_device, mce_dev);

arch/x86/kernel/cpu/mcheck/mce.c

+36 −22
Original line number Diff line number Diff line
@@ -85,6 +85,18 @@ static DECLARE_WAIT_QUEUE_HEAD(mce_wait); 
static DEFINE_PER_CPU(struct mce, mces_seen);

static int			cpu_missing;



static void default_decode_mce(struct mce *m)

{

	pr_emerg("No human readable MCE decoding support on this CPU type.\n");

	pr_emerg("Run the message through 'mcelog --ascii' to decode.\n");

}



/*

 * CPU/chipset specific EDAC code can register a callback here to print

 * MCE errors in a human-readable form:

 */

void (*x86_mce_decode_callback)(struct mce *m) = default_decode_mce;

EXPORT_SYMBOL(x86_mce_decode_callback);



/* MCA banks polled by the period polling timer for corrected events */

DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
@@ -165,46 +177,46 @@ void mce_log(struct mce *mce) 
	set_bit(0, &mce_need_notify);

}



void __weak decode_mce(struct mce *m)

{

	return;

}



static void print_mce(struct mce *m)

{

	printk(KERN_EMERG

	       "CPU %d: Machine Check Exception: %16Lx Bank %d: %016Lx\n",

	pr_emerg("CPU %d: Machine Check Exception: %16Lx Bank %d: %016Lx\n",

	       m->extcpu, m->mcgstatus, m->bank, m->status);



	if (m->ip) {

		printk(KERN_EMERG "RIP%s %02x:<%016Lx> ",

		pr_emerg("RIP%s %02x:<%016Lx> ",

			!(m->mcgstatus & MCG_STATUS_EIPV) ? " !INEXACT!" : "",

				m->cs, m->ip);



		if (m->cs == __KERNEL_CS)

			print_symbol("{%s}", m->ip);

		printk(KERN_CONT "\n");

		pr_cont("\n");

	}

	printk(KERN_EMERG "TSC %llx ", m->tsc);



	pr_emerg("TSC %llx ", m->tsc);

	if (m->addr)

		printk(KERN_CONT "ADDR %llx ", m->addr);

		pr_cont("ADDR %llx ", m->addr);

	if (m->misc)

		printk(KERN_CONT "MISC %llx ", m->misc);

	printk(KERN_CONT "\n");

	printk(KERN_EMERG "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x\n",

			m->cpuvendor, m->cpuid, m->time, m->socketid,

			m->apicid);

		pr_cont("MISC %llx ", m->misc);



	pr_cont("\n");

	pr_emerg("PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x\n",

		m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid);



	decode_mce(m);

	/*

	 * Print out human-readable details about the MCE error,

	 * (if the CPU has an implementation for that):

	 */

	x86_mce_decode_callback(m);

}



static void print_mce_head(void)

{

	printk(KERN_EMERG "\nHARDWARE ERROR\n");

	pr_emerg("\nHARDWARE ERROR\n");

}



static void print_mce_tail(void)

{

	printk(KERN_EMERG "This is not a software problem!\n"

	       "Run through mcelog --ascii to decode and contact your hardware vendor\n");

	pr_emerg("This is not a software problem!\n");

}



#define PANIC_TIMEOUT 5 /* 5 seconds */
@@ -218,6 +230,7 @@ static atomic_t mce_fake_paniced; 
static void wait_for_panic(void)

{

	long timeout = PANIC_TIMEOUT*USEC_PER_SEC;



	preempt_disable();

	local_irq_enable();

	while (timeout-- > 0)
@@ -285,6 +298,7 @@ static void mce_panic(char *msg, struct mce *final, char *exp) 
static int msr_to_offset(u32 msr)

{

	unsigned bank = __get_cpu_var(injectm.bank);



	if (msr == rip_msr)

		return offsetof(struct mce, ip);

	if (msr == MSR_IA32_MCx_STATUS(bank))

drivers/edac/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ edac_core-objs += edac_pci.o edac_pci_sysfs.o 
endif



ifdef CONFIG_CPU_SUP_AMD

edac_core-objs  += edac_mce_amd.o

obj-$(CONFIG_X86_MCE)			+= edac_mce_amd.o

endif



obj-$(CONFIG_EDAC_AMD76X)		+= amd76x_edac.o

drivers/edac/edac_mce_amd.c

+14 −1
Original line number Diff line number Diff line
@@ -362,7 +362,7 @@ static inline void amd_decode_err_code(unsigned int ec) 
		pr_warning("Huh? Unknown MCE error 0x%x\n", ec);

}



void decode_mce(struct mce *m)

static void amd_decode_mce(struct mce *m)

{

	struct err_regs regs;

	int node, ecc;
@@ -420,3 +420,16 @@ void decode_mce(struct mce *m) 


	amd_decode_err_code(m->status & 0xffff);

}



static int __init mce_amd_init(void)

{

	/*

	 * We can decode MCEs for Opteron and later CPUs:

	 */

	if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) &&

	    (boot_cpu_data.x86 >= 0xf))

		x86_mce_decode_callback = amd_decode_mce;



	return 0;

}

early_initcall(mce_amd_init);

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