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Commit c953cc98 authored by Dan Williams's avatar Dan Williams Committed by Dave Jiang
Browse files

libnvdimm, pmem: Restore page attributes when clearing errors 



Use clear_mce_nospec() to restore WB mode for the kernel linear mapping
of a pmem page that was marked 'HWPoison'. A page with 'HWPoison' set
has also been marked UC in PAT (page attribute table) via
set_mce_nospec() to prevent speculative retrievals of poison.

The 'HWPoison' flag is only cleared when overwriting an entire page.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
parent 284ce401

drivers/nvdimm/pmem.c

+26 −0
Original line number Original line Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/hdreg.h>

#include <linux/hdreg.h>

#include <linux/init.h>

#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/platform_device.h>

#include <linux/set_memory.h>

#include <linux/module.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/moduleparam.h>

#include <linux/badblocks.h>

#include <linux/badblocks.h>
@@ -51,6 +52,30 @@ static struct nd_region *to_region(struct pmem_device *pmem) 
	return to_nd_region(to_dev(pmem)->parent);

	return to_nd_region(to_dev(pmem)->parent);

}

}





static void hwpoison_clear(struct pmem_device *pmem,

		phys_addr_t phys, unsigned int len)

{

	unsigned long pfn_start, pfn_end, pfn;



	/* only pmem in the linear map supports HWPoison */

	if (is_vmalloc_addr(pmem->virt_addr))

		return;



	pfn_start = PHYS_PFN(phys);

	pfn_end = pfn_start + PHYS_PFN(len);

	for (pfn = pfn_start; pfn < pfn_end; pfn++) {

		struct page *page = pfn_to_page(pfn);



		/*

		 * Note, no need to hold a get_dev_pagemap() reference

		 * here since we're in the driver I/O path and

		 * outstanding I/O requests pin the dev_pagemap.

		 */

		if (test_and_clear_pmem_poison(page))

			clear_mce_nospec(pfn);

	}

}



static blk_status_t pmem_clear_poison(struct pmem_device *pmem,

static blk_status_t pmem_clear_poison(struct pmem_device *pmem,

		phys_addr_t offset, unsigned int len)

		phys_addr_t offset, unsigned int len)

{

{
@@ -65,6 +90,7 @@ static blk_status_t pmem_clear_poison(struct pmem_device *pmem, 
	if (cleared < len)

	if (cleared < len)

		rc = BLK_STS_IOERR;

		rc = BLK_STS_IOERR;

	if (cleared > 0 && cleared / 512) {

	if (cleared > 0 && cleared / 512) {

		hwpoison_clear(pmem, pmem->phys_addr + offset, cleared);

		cleared /= 512;

		cleared /= 512;

		dev_dbg(dev, "%#llx clear %ld sector%s\n",

		dev_dbg(dev, "%#llx clear %ld sector%s\n",

				(unsigned long long) sector, cleared,

				(unsigned long long) sector, cleared,

drivers/nvdimm/pmem.h

+13 −0
Original line number Original line Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __NVDIMM_PMEM_H__

#ifndef __NVDIMM_PMEM_H__

#define __NVDIMM_PMEM_H__

#define __NVDIMM_PMEM_H__

#include <linux/page-flags.h>

#include <linux/badblocks.h>

#include <linux/badblocks.h>

#include <linux/types.h>

#include <linux/types.h>

#include <linux/pfn_t.h>

#include <linux/pfn_t.h>
@@ -27,4 +28,16 @@ struct pmem_device { 




long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,

long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,

		long nr_pages, void **kaddr, pfn_t *pfn);

		long nr_pages, void **kaddr, pfn_t *pfn);



#ifdef CONFIG_MEMORY_FAILURE

static inline bool test_and_clear_pmem_poison(struct page *page)

{

	return TestClearPageHWPoison(page);

}

#else

static inline bool test_and_clear_pmem_poison(struct page *page)

{

	return false;

}

#endif

#endif /* __NVDIMM_PMEM_H__ */
 
#endif /* __NVDIMM_PMEM_H__ */