Update the definition of memcpy_from_pmem() to return 0 or -EIO on
error. Implement x86::arch_memcpy_from_pmem() with memcpy_mcsafe().
Cc: Borislav Petkov <b...@alien8.de>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Tony Luck <tony.l...@intel.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Ross Zwisler <ross.zwis...@linux.intel.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
Andrew, now that all the pre-requisites for this patch are in -next
(tip/core/ras, tip/x86/asm, nvdimm/libnvdimm-for-next) may I ask you to
carry it in -mm?
Alternatively I can do an octopus merge and post a branch, but that
seems messy/risky for me to be merging 3 branches that are still subject
to a merge window disposition.
arch/x86/include/asm/pmem.h | 9 +++++++++
drivers/nvdimm/pmem.c | 4 ++--
include/linux/pmem.h | 14 ++++++++------
3 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
index bf8b35d2035a..4df3820535c6 100644
--- a/arch/x86/include/asm/pmem.h
+++ b/arch/x86/include/asm/pmem.h
@@ -47,6 +47,15 @@ static inline void arch_memcpy_to_pmem(void __pmem *dst,
const void *src,
BUG();
}
+static inline int arch_memcpy_from_pmem(void *dst, const void __pmem *src,
+ size_t n)
+{
+ if (static_cpu_has(X86_FEATURE_MCE_RECOVERY))
+ return memcpy_mcsafe(dst, (void __force *) src, n) ? 0 : -EIO;
+ memcpy(dst, (void __force *) src, n);
+ return 0;
+}
+
/**
* arch_wmb_pmem - synchronize writes to persistent memory
*
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index adc387236fe7..2022d08c60ce 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -98,7 +98,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page
*page,
if (unlikely(bad_pmem))
rc = -EIO;
else {
- memcpy_from_pmem(mem + off, pmem_addr, len);
+ rc = memcpy_from_pmem(mem + off, pmem_addr, len);
flush_dcache_page(page);
}
} else {
@@ -295,7 +295,7 @@ static int pmem_rw_bytes(struct nd_namespace_common *ndns,
if (unlikely(is_bad_pmem(&pmem->bb, offset / 512, sz_align)))
return -EIO;
- memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
+ return memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
} else {
memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
wmb_pmem();
diff --git a/include/linux/pmem.h b/include/linux/pmem.h
index 3ec5309e29f3..c46c5cf6538e 100644
--- a/include/linux/pmem.h
+++ b/include/linux/pmem.h
@@ -66,14 +66,16 @@ static inline void arch_invalidate_pmem(void __pmem *addr,
size_t size)
#endif
/*
- * Architectures that define ARCH_HAS_PMEM_API must provide
- * implementations for arch_memcpy_to_pmem(), arch_wmb_pmem(),
- * arch_copy_from_iter_pmem(), arch_clear_pmem(), arch_wb_cache_pmem()
- * and arch_has_wmb_pmem().
+ * memcpy_from_pmem - read from persistent memory with error handling
+ * @dst: destination buffer
+ * @src: source buffer
+ *
+ * Returns 0 on success -EIO on failure.
*/
-static inline void memcpy_from_pmem(void *dst, void __pmem const *src, size_t
size)
+static inline int memcpy_from_pmem(void *dst, void __pmem const *src,
+ size_t size)
{
- memcpy(dst, (void __force const *) src, size);
+ return arch_memcpy_from_pmem(dst, src, size);
}
static inline bool arch_has_pmem_api(void)
