Commit c545f5e4 authored by Qiuxu Zhuo's avatar Qiuxu Zhuo Committed by Tony Luck
Browse files

EDAC/i10nm: Skip the absent memory controllers 



Some Sapphire Rapids workstations' absent memory controllers
still appear as PCIe devices that fool the i10nm_edac driver
and result in "shift exponent -66 is negative" call traces
from skx_get_dimm_info().

Skip the absent memory controllers to avoid the call traces.

Reported-by: default avatarKai-Heng Feng <kai.heng.feng@canonical.com>
Closes: https://lore.kernel.org/linux-edac/CAAd53p41Ku1m1rapeqb1xtD+kKuk+BaUW=dumuoF0ZO3GhFjFA@mail.gmail.com/T/#m5de16dce60a8c836ec235868c7c16e3fefad0cc2


Tested-by: default avatarKai-Heng Feng <kai.heng.feng@canonical.com>
Reported-by: default avatarKoba Ko <koba.ko@canonical.com>
Closes: https://lore.kernel.org/linux-edac/SA1PR11MB71305B71CCCC3D9305835202892AA@SA1PR11MB7130.namprd11.prod.outlook.com/T/#t


Tested-by: default avatarKoba Ko <koba.ko@canonical.com>
Fixes: d4dc89d0 ("EDAC, i10nm: Add a driver for Intel 10nm server processors")
Signed-off-by: default avatarQiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20230710013232.59712-1-qiuxu.zhuo@intel.com
parent 6eaae198

drivers/edac/i10nm_base.c

+49 −5
Original line number Diff line number Diff line
@@ -658,13 +658,49 @@ static struct pci_dev *get_ddr_munit(struct skx_dev *d, int i, u32 *offset, unsi 
	return mdev;

}



/**

 * i10nm_imc_absent() - Check whether the memory controller @imc is absent

 *

 * @imc    : The pointer to the structure of memory controller EDAC device.

 *

 * RETURNS : true if the memory controller EDAC device is absent, false otherwise.

 */

static bool i10nm_imc_absent(struct skx_imc *imc)

{

	u32 mcmtr;

	int i;



	switch (res_cfg->type) {

	case SPR:

		for (i = 0; i < res_cfg->ddr_chan_num; i++) {

			mcmtr = I10NM_GET_MCMTR(imc, i);

			edac_dbg(1, "ch%d mcmtr reg %x\n", i, mcmtr);

			if (mcmtr != ~0)

				return false;

		}



		/*

		 * Some workstations' absent memory controllers still

		 * appear as PCIe devices, misleading the EDAC driver.

		 * By observing that the MMIO registers of these absent

		 * memory controllers consistently hold the value of ~0.

		 *

		 * We identify a memory controller as absent by checking

		 * if its MMIO register "mcmtr" == ~0 in all its channels.

		 */

		return true;

	default:

		return false;

	}

}



static int i10nm_get_ddr_munits(void)

{

	struct pci_dev *mdev;

	void __iomem *mbase;

	unsigned long size;

	struct skx_dev *d;

	int i, j = 0;

	int i, lmc, j = 0;

	u32 reg, off;

	u64 base;
@@ -690,7 +726,7 @@ static int i10nm_get_ddr_munits(void) 
		edac_dbg(2, "socket%d mmio base 0x%llx (reg 0x%x)\n",

			 j++, base, reg);



		for (i = 0; i < res_cfg->ddr_imc_num; i++) {

		for (lmc = 0, i = 0; i < res_cfg->ddr_imc_num; i++) {

			mdev = get_ddr_munit(d, i, &off, &size);



			if (i == 0 && !mdev) {
@@ -700,8 +736,6 @@ static int i10nm_get_ddr_munits(void) 
			if (!mdev)

				continue;



			d->imc[i].mdev = mdev;



			edac_dbg(2, "mc%d mmio base 0x%llx size 0x%lx (reg 0x%x)\n",

				 i, base + off, size, reg);
@@ -712,7 +746,17 @@ static int i10nm_get_ddr_munits(void) 
				return -ENODEV;

			}



			d->imc[i].mbase = mbase;

			d->imc[lmc].mbase = mbase;

			if (i10nm_imc_absent(&d->imc[lmc])) {

				pci_dev_put(mdev);

				iounmap(mbase);

				d->imc[lmc].mbase = NULL;

				edac_dbg(2, "Skip absent mc%d\n", i);

				continue;

			} else {

				d->imc[lmc].mdev = mdev;

				lmc++;

			}

		}

	}