[tip:x86/urgent] x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()

[tip-bot for Tony Luck]

Commit-ID:  cbf8b5a2b649a501758291cb4d4ba1e5711771ba
Gitweb: http://git.kernel.org/tip/cbf8b5a2b649a501758291cb4d4ba1e5711771ba
Author: Tony Luck 
AuthorDate: Mon, 14 Mar 2016 15:33:39 -0700
Committer:  Ingo Molnar 
CommitDate: Wed, 16 Mar 2016 09:02:18 +0100

x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()

Returning a 'bool' was very unpopular. Doubly so because the
code was just wrong (returning zero for true, one for false;
great for shell programming, not so good for C).

Change return type to "int". Keep zero as the success indicator
because it matches other similar code and people may be more
comfortable writing:

if (memcpy_mcsafe(to, from, count)) {
printk("Sad panda, copy failed\n");
...
}

Make the failure return value -EFAULT for now.

Reported by: Mika Penttilä 
Signed-off-by: Tony Luck 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: mika.pentt...@nextfour.com
Fixes: 92b0729c34ca ("x86/mm, x86/mce: Add memcpy_mcsafe()")
Link: 
http://lkml.kernel.org/r/695f14233fa7a54fcac4406c706d7fec228e3f4c.1457993040.git.tony.l...@intel.com
Signed-off-by: Ingo Molnar 
---
 arch/x86/include/asm/string_64.h | 4 ++--
 arch/x86/lib/memcpy_64.S | 7 ---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index ca6ba36..90dbbd9 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -87,9 +87,9 @@ int strcmp(const char *cs, const char *ct);
  *
  * Low level memory copy function that catches machine checks
  *
- * Return true for success, false for fail
+ * Return 0 for success, -EFAULT for fail
  */
-bool memcpy_mcsafe(void *dst, const void *src, size_t cnt);
+int memcpy_mcsafe(void *dst, const void *src, size_t cnt);
 
 #endif /* __KERNEL__ */
 
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index cbb8ee5..2ec0b0abb 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -1,6 +1,7 @@
 /* Copyright 2002 Andi Kleen */
 
 #include 
+#include 
 #include 
 #include 
 
@@ -268,16 +269,16 @@ ENTRY(memcpy_mcsafe)
decl %ecx
jnz .L_copy_trailing_bytes
 
-   /* Copy successful. Return true */
+   /* Copy successful. Return zero */
 .L_done_memcpy_trap:
xorq %rax, %rax
ret
 ENDPROC(memcpy_mcsafe)
 
.section .fixup, "ax"
-   /* Return false for any failure */
+   /* Return -EFAULT for any failure */
 .L_memcpy_mcsafe_fail:
-   mov $1, %rax
+   mov $-EFAULT, %rax
ret
 
.previous

[tip:x86/urgent] x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()

[tip-bot for Tony Luck]

Commit-ID:  cbf8b5a2b649a501758291cb4d4ba1e5711771ba
Gitweb: http://git.kernel.org/tip/cbf8b5a2b649a501758291cb4d4ba1e5711771ba
Author: Tony Luck 
AuthorDate: Mon, 14 Mar 2016 15:33:39 -0700
Committer:  Ingo Molnar 
CommitDate: Wed, 16 Mar 2016 09:02:18 +0100

x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()

Returning a 'bool' was very unpopular. Doubly so because the
code was just wrong (returning zero for true, one for false;
great for shell programming, not so good for C).

Change return type to "int". Keep zero as the success indicator
because it matches other similar code and people may be more
comfortable writing:

if (memcpy_mcsafe(to, from, count)) {
printk("Sad panda, copy failed\n");
...
}

Make the failure return value -EFAULT for now.

Reported by: Mika Penttilä 
Signed-off-by: Tony Luck 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Dan Williams 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: mika.pentt...@nextfour.com
Fixes: 92b0729c34ca ("x86/mm, x86/mce: Add memcpy_mcsafe()")
Link: 
http://lkml.kernel.org/r/695f14233fa7a54fcac4406c706d7fec228e3f4c.1457993040.git.tony.l...@intel.com
Signed-off-by: Ingo Molnar 
---
 arch/x86/include/asm/string_64.h | 4 ++--
 arch/x86/lib/memcpy_64.S | 7 ---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index ca6ba36..90dbbd9 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -87,9 +87,9 @@ int strcmp(const char *cs, const char *ct);
  *
  * Low level memory copy function that catches machine checks
  *
- * Return true for success, false for fail
+ * Return 0 for success, -EFAULT for fail
  */
-bool memcpy_mcsafe(void *dst, const void *src, size_t cnt);
+int memcpy_mcsafe(void *dst, const void *src, size_t cnt);
 
 #endif /* __KERNEL__ */
 
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index cbb8ee5..2ec0b0abb 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -1,6 +1,7 @@
 /* Copyright 2002 Andi Kleen */
 
 #include 
+#include 
 #include 
 #include 
 
@@ -268,16 +269,16 @@ ENTRY(memcpy_mcsafe)
decl %ecx
jnz .L_copy_trailing_bytes
 
-   /* Copy successful. Return true */
+   /* Copy successful. Return zero */
 .L_done_memcpy_trap:
xorq %rax, %rax
ret
 ENDPROC(memcpy_mcsafe)
 
.section .fixup, "ax"
-   /* Return false for any failure */
+   /* Return -EFAULT for any failure */
 .L_memcpy_mcsafe_fail:
-   mov $1, %rax
+   mov $-EFAULT, %rax
ret
 
.previous