Commit f4347553 authored by Borislav Petkov's avatar Borislav Petkov
Browse files

amd64_edac: Remove polling mechanism 



Switch to reusing the mcheck core's machine check polling mechanism
instead of duplicating functionality by using the EDAC polling routine.

Correct formatting while at it.

Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
Acked-by: default avatarDoug Thompson <dougthompson@xmission.com>
parent 98a5ae2d

drivers/edac/amd64_edac.c

+0 −118
Original line number Diff line number Diff line
@@ -1978,107 +1978,6 @@ static int get_channel_from_ecc_syndrome(struct mem_ctl_info *mci, u16 syndrome) 
	return map_err_sym_to_channel(err_sym, pvt->syn_type);

}



/*

 * Check for valid error in the NB Status High register. If so, proceed to read

 * NB Status Low, NB Address Low and NB Address High registers and store data

 * into error structure.

 *

 * Returns:

 *	- 1: if hardware regs contains valid error info

 *	- 0: if no valid error is indicated

 */

static int amd64_get_error_info_regs(struct mem_ctl_info *mci,

				     struct err_regs *regs)

{

	struct amd64_pvt *pvt;

	struct pci_dev *misc_f3_ctl;



	pvt = mci->pvt_info;

	misc_f3_ctl = pvt->misc_f3_ctl;



	if (amd64_read_pci_cfg(misc_f3_ctl, K8_NBSH, &regs->nbsh))

		return 0;



	if (!(regs->nbsh & K8_NBSH_VALID_BIT))

		return 0;



	/* valid error, read remaining error information registers */

	if (amd64_read_pci_cfg(misc_f3_ctl, K8_NBSL, &regs->nbsl) ||

	    amd64_read_pci_cfg(misc_f3_ctl, K8_NBEAL, &regs->nbeal) ||

	    amd64_read_pci_cfg(misc_f3_ctl, K8_NBEAH, &regs->nbeah) ||

	    amd64_read_pci_cfg(misc_f3_ctl, K8_NBCFG, &regs->nbcfg))

		return 0;



	return 1;

}



/*

 * This function is called to retrieve the error data from hardware and store it

 * in the info structure.

 *

 * Returns:

 *	- 1: if a valid error is found

 *	- 0: if no error is found

 */

static int amd64_get_error_info(struct mem_ctl_info *mci,

				struct err_regs *info)

{

	struct amd64_pvt *pvt;

	struct err_regs regs;



	pvt = mci->pvt_info;



	if (!amd64_get_error_info_regs(mci, info))

		return 0;



	/*

	 * Here's the problem with the K8's EDAC reporting: There are four

	 * registers which report pieces of error information. They are shared

	 * between CEs and UEs. Furthermore, contrary to what is stated in the

	 * BKDG, the overflow bit is never used! Every error always updates the

	 * reporting registers.

	 *

	 * Can you see the race condition? All four error reporting registers

	 * must be read before a new error updates them! There is no way to read

	 * all four registers atomically. The best than can be done is to detect

	 * that a race has occured and then report the error without any kind of

	 * precision.

	 *

	 * What is still positive is that errors are still reported and thus

	 * problems can still be detected - just not localized because the

	 * syndrome and address are spread out across registers.

	 *

	 * Grrrrr!!!!!  Here's hoping that AMD fixes this in some future K8 rev.

	 * UEs and CEs should have separate register sets with proper overflow

	 * bits that are used! At very least the problem can be fixed by

	 * honoring the ErrValid bit in 'nbsh' and not updating registers - just

	 * set the overflow bit - unless the current error is CE and the new

	 * error is UE which would be the only situation for overwriting the

	 * current values.

	 */



	regs = *info;



	/* Use info from the second read - most current */

	if (unlikely(!amd64_get_error_info_regs(mci, info)))

		return 0;



	/* clear the error bits in hardware */

	pci_write_bits32(pvt->misc_f3_ctl, K8_NBSH, 0, K8_NBSH_VALID_BIT);



	/* Check for the possible race condition */

	if ((regs.nbsh != info->nbsh) ||

	     (regs.nbsl != info->nbsl) ||

	     (regs.nbeah != info->nbeah) ||

	     (regs.nbeal != info->nbeal)) {

		amd64_mc_printk(mci, KERN_WARNING,

				"hardware STATUS read access race condition "

				"detected!\n");

		return 0;

	}

	return 1;

}



/*

 * Handle any Correctable Errors (CEs) that have occurred. Check for valid ERROR

 * ADDRESS and process.
@@ -2202,20 +2101,6 @@ void amd64_decode_bus_error(int node_id, struct err_regs *regs) 


}



/*

 * The main polling 'check' function, called FROM the edac core to perform the

 * error checking and if an error is encountered, error processing.

 */

static void amd64_check(struct mem_ctl_info *mci)

{

	struct err_regs regs;



	if (amd64_get_error_info(mci, &regs)) {

		struct amd64_pvt *pvt = mci->pvt_info;

		amd_decode_nb_mce(pvt->mc_node_id, &regs, 1);

	}

}



/*

 * Input:

 *	1) struct amd64_pvt which contains pvt->dram_f2_ctl pointer
@@ -2756,9 +2641,6 @@ static void amd64_setup_mci_misc_attributes(struct mem_ctl_info *mci) 
	mci->dev_name		= pci_name(pvt->dram_f2_ctl);

	mci->ctl_page_to_phys	= NULL;



	/* IMPORTANT: Set the polling 'check' function in this module */

	mci->edac_check		= amd64_check;



	/* memory scrubber interface */

	mci->set_sdram_scrub_rate = amd64_set_scrub_rate;

	mci->get_sdram_scrub_rate = amd64_get_scrub_rate;

drivers/edac/edac_mce_amd.c

+8 −8

File changed.

Contains only whitespace changes.