Patch "m68k/uaccess: Fix asm constraints for userspace access" has been added to the 3.10-stable tree

PATCH [email protected] 1 participant 1 message Oct 23, 2015

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2015-10-23 14:13 UTC #0 lore raw

This is a note to let you know that I've just added the patch titled

m68k/uaccess: Fix asm constraints for userspace access

to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
m68k-uaccess-fix-asm-constraints-for-userspace-access.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 631d8b674f5f8235e9cb7e628b0fe9e5200e3158 Mon Sep 17 00:00:00 2001

From: Geert Uytterhoeven <[email protected]>
Date: Sun, 9 Jun 2013 20:12:42 +0200
Subject: m68k/uaccess: Fix asm constraints for userspace access

From: Geert Uytterhoeven <[email protected]>

commit 631d8b674f5f8235e9cb7e628b0fe9e5200e3158 upstream.

When compiling a MMU kernel with CPU_HAS_ADDRESS_SPACES=n (e.g. "MMU=y allnoconfig": "echo CONFIG_MMU=y > allno.config && make KCONFIG_ALLCONFIG=1 allnoconfig"), we use plain "move" instead of "moves", and I got:

CC arch/m68k/lib/uaccess.o
{standard input}: Assembler messages:
{standard input}:47: Error: operands mismatch -- statement `move.b %a0,(%a1)' ignored

This happens because plain "move" doesn't support byte transfers between memory and address registers, while "moves" does.

Fix the asm constraints for __generic_copy_from_user(), __generic_copy_to_user(), and __clear_user() to only use data registers when accessing userspace.

Also, relax the asm constraints for 16-bit userspace accesses in __put_user() and __get_user(), as both "move" and "moves" do support such transfers between memory and address registers.

Signed-off-by Geert Uytterhoeven <[email protected]>

Cc Guenter Roeck <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 arch/m68k/include/asm/uaccess_mm.h |    8 ++++----
 arch/m68k/lib/uaccess.c            |    6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

arch/m68k/include/asm/uaccess_mm.h +4 -4

@@ -90,7 +90,7 @@ asm volatile ("\n"					\
 		__put_user_asm(__pu_err, __pu_val, ptr, b, d, -EFAULT);	\
 		break;							\
 	case 2:								\
-		__put_user_asm(__pu_err, __pu_val, ptr, w, d, -EFAULT);	\
+		__put_user_asm(__pu_err, __pu_val, ptr, w, r, -EFAULT);	\
 		break;							\
 	case 4:								\
 		__put_user_asm(__pu_err, __pu_val, ptr, l, r, -EFAULT);	\

@@ -158,7 +158,7 @@ asm volatile ("\n"					\
 		__get_user_asm(__gu_err, x, ptr, u8, b, d, -EFAULT);	\
 		break;							\
 	case 2:								\
-		__get_user_asm(__gu_err, x, ptr, u16, w, d, -EFAULT);	\
+		__get_user_asm(__gu_err, x, ptr, u16, w, r, -EFAULT);	\
 		break;							\
 	case 4:								\
 		__get_user_asm(__gu_err, x, ptr, u32, l, r, -EFAULT);	\

@@ -245,7 +245,7 @@ __constant_copy_from_user(void *to, cons
 		__get_user_asm(res, *(u8 *)to, (u8 __user *)from, u8, b, d, 1);
 		break;
 	case 2:
-		__get_user_asm(res, *(u16 *)to, (u16 __user *)from, u16, w, d, 2);
+		__get_user_asm(res, *(u16 *)to, (u16 __user *)from, u16, w, r, 2);
 		break;
 	case 3:
 		__constant_copy_from_user_asm(res, to, from, tmp, 3, w, b,);

@@ -326,7 +326,7 @@ __constant_copy_to_user(void __user *to,
 		__put_user_asm(res, *(u8 *)from, (u8 __user *)to, b, d, 1);
 		break;
 	case 2:
-		__put_user_asm(res, *(u16 *)from, (u16 __user *)to, w, d, 2);
+		__put_user_asm(res, *(u16 *)from, (u16 __user *)to, w, r, 2);
 		break;
 	case 3:
 		__constant_copy_to_user_asm(res, to, from, tmp, 3, w, b,);

arch/m68k/lib/uaccess.c +3 -3

@@ -52,7 +52,7 @@ unsigned long __generic_copy_from_user(v
 		"	.long	3b,30b\n"
 		"	.long	5b,50b\n"
 		"	.previous"
-		: "=d" (res), "+a" (from), "+a" (to), "=&r" (tmp)
+		: "=d" (res), "+a" (from), "+a" (to), "=&d" (tmp)
 		: "0" (n / 4), "d" (n & 3));
 
 	return res;

@@ -96,7 +96,7 @@ unsigned long __generic_copy_to_user(voi
 		"	.long	7b,50b\n"
 		"	.long	8b,50b\n"
 		"	.previous"
-		: "=d" (res), "+a" (from), "+a" (to), "=&r" (tmp)
+		: "=d" (res), "+a" (from), "+a" (to), "=&d" (tmp)
 		: "0" (n / 4), "d" (n & 3));
 
 	return res;

@@ -141,7 +141,7 @@ unsigned long __clear_user(void __user *
 		"	.long	7b,40b\n"
 		"	.previous"
 		: "=d" (res), "+a" (to)
-		: "r" (0), "0" (n / 4), "d" (n & 3));
+		: "d" (0), "0" (n / 4), "d" (n & 3));
 
     return res;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-3.10/m68k-uaccess-fix-asm-constraints-for-userspace-access.patch