On Mon, Mar 28, 2016 at 5:28 PM, Dan Williams <dan.j.willi...@intel.com> wrote:
> Update the definition of memcpy_from_pmem() to return 0 or a negative
> error code. 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: Linus Torvalds <torva...@linux-foundation.org>
> Reviewed-by: Ross Zwisler <ross.zwis...@linux.intel.com>
> Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
> ---
> arch/x86/include/asm/pmem.h | 9 +++++++++
> drivers/nvdimm/pmem.c | 4 ++--
> include/linux/pmem.h | 21 +++++++++++++++------
> 3 files changed, 26 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
> index bf8b35d2035a..fbc5e92e1ecc 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);
> + 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 ca5721c306bb..cc31c6f1f88e 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -99,7 +99,7 @@ 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..cc948191a653 100644
> --- a/include/linux/pmem.h
> +++ b/include/linux/pmem.h
> @@ -42,6 +42,12 @@ 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)
> +{
> + BUG();
> +}
Note, the change in v3 was the addition of this stub to fix a build
error on !CONFIG_ARCH_HAS_PMEM_API archs.
