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From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: hch@lst.de, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	jack@suse.cz
Subject: [PATCH v3 12/12] libnvdimm, pmem: Restore page attributes when clearing errors
Date: Mon, 04 Jun 2018 16:12:43 -0700	[thread overview]
Message-ID: <152815396335.39010.17157370539429298762.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <152815389835.39010.13253559944508110923.stgit@dwillia2-desk3.amr.corp.intel.com>

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: Dan Williams <dan.j.williams@intel.com>
---
 drivers/nvdimm/pmem.c |   26 ++++++++++++++++++++++++++
 drivers/nvdimm/pmem.h |   13 +++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 9d714926ecf5..04ee1fdee219 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -20,6 +20,7 @@
 #include <linux/hdreg.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
+#include <linux/set_memory.h>
 #include <linux/module.h>
 #include <linux/moduleparam.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);
 }
 
+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,
 		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)
 		rc = BLK_STS_IOERR;
 	if (cleared > 0 && cleared / 512) {
+		hwpoison_clear(pmem, pmem->phys_addr + offset, cleared);
 		cleared /= 512;
 		dev_dbg(dev, "%#llx clear %ld sector%s\n",
 				(unsigned long long) sector, cleared,
diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h
index a64ebc78b5df..59cfe13ea8a8 100644
--- a/drivers/nvdimm/pmem.h
+++ b/drivers/nvdimm/pmem.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __NVDIMM_PMEM_H__
 #define __NVDIMM_PMEM_H__
+#include <linux/page-flags.h>
 #include <linux/badblocks.h>
 #include <linux/types.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 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__ */

      parent reply	other threads:[~2018-06-04 23:12 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-04 23:11 [PATCH v3 00/12] mm: Teach memory_failure() about ZONE_DEVICE pages Dan Williams
2018-06-04 23:11 ` [PATCH v3 01/12] device-dax: Convert to vmf_insert_mixed and vm_fault_t Dan Williams
2018-06-04 23:11 ` [PATCH v3 02/12] device-dax: Cleanup vm_fault de-reference chains Dan Williams
2018-06-04 23:11 ` [PATCH v3 03/12] device-dax: Enable page_mapping() Dan Williams
2018-06-07 15:39   ` Jan Kara
2018-06-04 23:12 ` [PATCH v3 04/12] device-dax: Set page->index Dan Williams
2018-06-07 15:50   ` Jan Kara
2018-06-04 23:12 ` [PATCH v3 05/12] filesystem-dax: " Dan Williams
2018-06-07 16:02   ` Jan Kara
2018-06-04 23:12 ` [PATCH v3 06/12] mm, madvise_inject_error: Let memory_failure() optionally take a page reference Dan Williams
2018-06-04 23:12 ` [PATCH v3 07/12] x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses Dan Williams
2018-06-04 23:12 ` [PATCH v3 08/12] x86/memory_failure: Introduce {set, clear}_mce_nospec() Dan Williams
2018-06-07  4:42   ` Dan Williams
2018-06-07 17:02     ` Luck, Tony
2018-06-04 23:12 ` [PATCH v3 09/12] mm, memory_failure: Pass page size to kill_proc() Dan Williams
2018-06-04 23:12 ` [PATCH v3 10/12] mm, memory_failure: Fix page->mapping assumptions relative to the page lock Dan Williams
2018-06-04 23:12 ` [PATCH v3 11/12] mm, memory_failure: Teach memory_failure() about dev_pagemap pages Dan Williams
2018-06-07  4:22   ` Dan Williams
2018-06-07 16:30   ` Jan Kara
2018-06-07 16:45     ` Dan Williams
2018-06-04 23:12 ` Dan Williams [this message]

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