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Commit 11797742 authored by Matt Redfearn's avatar Matt Redfearn Committed by Greg Kroah-Hartman
Browse files

MIPS: uaccess: Add micromips clobbers to bzero invocation 



commit b3d7e55c3f886493235bfee08e1e5a4a27cbcce8 upstream.

The micromips implementation of bzero additionally clobbers registers t7
& t8. Specify this in the clobbers list when invoking bzero.

Fixes: 26c5e07d ("MIPS: microMIPS: Optimise 'memset' core library function.")
Reported-by: default avatarJames Hogan <jhogan@kernel.org>
Signed-off-by: default avatarMatt Redfearn <matt.redfearn@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.10+
Patchwork: https://patchwork.linux-mips.org/patch/19110/


Signed-off-by: default avatarJames Hogan <jhogan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d385cc69

arch/mips/include/asm/uaccess.h

+9 −2
Original line number Diff line number Diff line
@@ -1257,6 +1257,13 @@ __clear_user(void __user *addr, __kernel_size_t size) 
{

	__kernel_size_t res;



#ifdef CONFIG_CPU_MICROMIPS

/* micromips memset / bzero also clobbers t7 & t8 */

#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$15", "$24", "$31"

#else

#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$31"

#endif /* CONFIG_CPU_MICROMIPS */



	if (eva_kernel_access()) {

		__asm__ __volatile__(

			"move\t$4, %1\n\t"
@@ -1266,7 +1273,7 @@ __clear_user(void __user *addr, __kernel_size_t size) 
			"move\t%0, $6"

			: "=r" (res)

			: "r" (addr), "r" (size)

			: "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");

			: bzero_clobbers);

	} else {

		might_fault();

		__asm__ __volatile__(
@@ -1277,7 +1284,7 @@ __clear_user(void __user *addr, __kernel_size_t size) 
			"move\t%0, $6"

			: "=r" (res)

			: "r" (addr), "r" (size)

			: "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");

			: bzero_clobbers);

	}



	return res;