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Commit 631d8b67 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven
Browse files

m68k/uaccess: Fix asm constraints for userspace access 



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: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 957d6bf6

arch/m68k/include/asm/uaccess_mm.h

+4 −4
Original line number Diff line number Diff line
@@ -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, const void __user *from, unsigned long n) 
		__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, const void *from, unsigned long n) 
		__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
Original line number Diff line number Diff line
@@ -52,7 +52,7 @@ unsigned long __generic_copy_from_user(void *to, const void __user *from, 
		"	.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(void __user *to, const void *from, 
		"	.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 *to, unsigned long n) 
		"	.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;

}