4.4-stable review patch. If anyone has any objections, please let me know.
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From: Matt Redfearn matt.redfearn@mips.com
commit b3d7e55c3f886493235bfee08e1e5a4a27cbcce8 upstream.
The micromips implementation of bzero additionally clobbers registers t7 & t8. Specify this in the clobbers list when invoking bzero.
Fixes: 26c5e07d1478 ("MIPS: microMIPS: Optimise 'memset' core library function.") Reported-by: James Hogan jhogan@kernel.org Signed-off-by: Matt 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: James Hogan jhogan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/mips/include/asm/uaccess.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
--- a/arch/mips/include/asm/uaccess.h +++ b/arch/mips/include/asm/uaccess.h @@ -1238,6 +1238,13 @@ __clear_user(void __user *addr, __kernel { __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" @@ -1247,7 +1254,7 @@ __clear_user(void __user *addr, __kernel "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__( @@ -1258,7 +1265,7 @@ __clear_user(void __user *addr, __kernel "move\t%0, $6" : "=r" (res) : "r" (addr), "r" (size) - : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31"); + : bzero_clobbers); }
return res;