2016-04-13 00:19:27

by Kani, Toshimitsu

Subject: [PATCH] pmem: fix BUG() error in pmem.h:48 on X86_32

After 'commit fc0c2028135c ("x86, pmem: use memcpy_mcsafe()
for memcpy_from_pmem()")', probing a PMEM device hits the BUG()
error below on X86_32 kernel.

kernel BUG at include/linux/pmem.h:48!

memcpy_from_pmem() calls arch_memcpy_from_pmem(), which is
unimplemented since CONFIG_ARCH_HAS_PMEM_API is undefined on
X86_32.

Fix the BUG() error by adding default_memcpy_from_pmem().

Signed-off-by: Toshi Kani <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Ross Zwisler <[email protected]>
---
include/linux/pmem.h | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/include/linux/pmem.h b/include/linux/pmem.h
index ac6d872..57d146f 100644
--- a/include/linux/pmem.h
+++ b/include/linux/pmem.h
@@ -72,6 +72,18 @@ static inline void arch_invalidate_pmem(void __pmem *addr, size_t size)
}
#endif

+static inline bool arch_has_pmem_api(void)
+{
+ return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
+}
+
+static inline int default_memcpy_from_pmem(void *dst, void __pmem const *src,
+ size_t size)
+{
+ memcpy(dst, (void __force *) src, size);
+ return 0;
+}
+
/*
* memcpy_from_pmem - read from persistent memory with error handling
* @dst: destination buffer
@@ -83,12 +95,10 @@ static inline void arch_invalidate_pmem(void __pmem *addr, size_t size)
static inline int memcpy_from_pmem(void *dst, void __pmem const *src,
size_t size)
{
- return arch_memcpy_from_pmem(dst, src, size);
-}
-
-static inline bool arch_has_pmem_api(void)
-{
- return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
+ if (arch_has_pmem_api())
+ return arch_memcpy_from_pmem(dst, src, size);
+ else
+ return default_memcpy_from_pmem(dst, src, size);
}

/**

2016-04-13 05:24:27

by Dan Williams

Subject: Re: [PATCH] pmem: fix BUG() error in pmem.h:48 on X86_32

On Tue, Apr 12, 2016 at 5:10 PM, Toshi Kani <[email protected]> wrote:
> After 'commit fc0c2028135c ("x86, pmem: use memcpy_mcsafe()
> for memcpy_from_pmem()")', probing a PMEM device hits the BUG()
> error below on X86_32 kernel.
>
> kernel BUG at include/linux/pmem.h:48!
>
> memcpy_from_pmem() calls arch_memcpy_from_pmem(), which is
> unimplemented since CONFIG_ARCH_HAS_PMEM_API is undefined on
> X86_32.
>
> Fix the BUG() error by adding default_memcpy_from_pmem().
>
> Signed-off-by: Toshi Kani <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Ross Zwisler <[email protected]>

Whoops, I'll add a 32-bit boot test to my release criteria. Thanks Toshi!

2016-04-13 17:20:12

by Ross Zwisler

Subject: Re: [PATCH] pmem: fix BUG() error in pmem.h:48 on X86_32

On Tue, Apr 12, 2016 at 10:24:25PM -0700, Dan Williams wrote:
> On Tue, Apr 12, 2016 at 5:10 PM, Toshi Kani <[email protected]> wrote:
> > After 'commit fc0c2028135c ("x86, pmem: use memcpy_mcsafe()
> > for memcpy_from_pmem()")', probing a PMEM device hits the BUG()
> > error below on X86_32 kernel.
> >
> > kernel BUG at include/linux/pmem.h:48!
> >
> > memcpy_from_pmem() calls arch_memcpy_from_pmem(), which is
> > unimplemented since CONFIG_ARCH_HAS_PMEM_API is undefined on
> > X86_32.
> >
> > Fix the BUG() error by adding default_memcpy_from_pmem().
> >
> > Signed-off-by: Toshi Kani <[email protected]>
> > Cc: Dan Williams <[email protected]>
> > Cc: Ross Zwisler <[email protected]>
>
> Whoops, I'll add a 32-bit boot test to my release criteria. Thanks Toshi!

Yep, this patch looks correct to me.

Reviewed-by: Ross Zwisler <[email protected]>