pmem: fix BUG() error in pmem.h:48 on X86_32

After 'commit fc0c202 ("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(). Acked-by: Dan Williams <[email protected]> Signed-off-by: Toshi Kani <[email protected]> Signed-off-by: Ross Zwisler <[email protected]> Cc: Dan Williams <[email protected]> Cc: Ross Zwisler <[email protected]>
kyagi · Apr 14, 2016 · cba2e47 · cba2e47
1 parent bf16200
commit cba2e47
Showing 1 changed file with 16 additions and 6 deletions.
diff --git 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);
 }
 
 /**