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Message-ID: <1523973972-25633-2-git-send-email-matt.redfearn@mips.com>
Date: Tue, 17 Apr 2018 15:06:11 +0100
From: Matt Redfearn <matt.redfearn@...s.com>
To: James Hogan <jhogan@...nel.org>, Ralf Baechle <ralf@...ux-mips.org>
CC: <linux-mips@...ux-mips.org>,
Matt Redfearn <matt.redfearn@...s.com>,
<stable@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
Al Viro <viro@...iv.linux.org.uk>
Subject: [PATCH 2/3] MIPS: uaccess: Add micromips clobbers to bzero invocation
The micromips implementation of bzero additionally clobbers registers t7
& t8. Specify this in the clobbers list when invoking bzero.
Reported-by: James Hogan <jhogan@...nel.org>
Fixes: 26c5e07d1478 ("MIPS: microMIPS: Optimise 'memset' core library function.")
Cc: stable@...r.kernel.org
Signed-off-by: Matt Redfearn <matt.redfearn@...s.com>
---
arch/mips/include/asm/uaccess.h | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index b71306947290..06629011a434 100644
--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -654,6 +654,13 @@ __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"
@@ -663,7 +670,7 @@ __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__(
@@ -674,7 +681,7 @@ __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;
--
2.7.4
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