From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: [PATCH v2 11/11] libnvdimm, pmem: Restore page attributes when clearing errors From: Dan Williams To: linux-nvdimm@lists.01.org Cc: hch@lst.de, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, jack@suse.cz Date: Sat, 02 Jun 2018 22:23:41 -0700 Message-ID: <152800342137.17112.17757085615233828006.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <152800336321.17112.3300876636370683279.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152800336321.17112.3300876636370683279.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: 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 --- 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 #include #include +#include #include #include #include @@ -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 #include #include #include @@ -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__ */