[ARM32,v4.4,V2,34/47] ARM: 8795/1: spectre-v1.1: use put_user() for __put_user()

Message ID 89ae15bfdcc72b42ebacde01603f09fd5cd880b7.1564646727.git.viresh.kumar@linaro.org
State New
Headers show
Series
  • V4.4 backport of arm32 Spectre patches
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Commit Message

Viresh Kumar Aug. 1, 2019, 8:16 a.m.
From: Julien Thierry <julien.thierry@arm.com>


Commit e3aa6243434fd9a82e84bb79ab1abd14f2d9a5a7 upstream.

When Spectre mitigation is required, __put_user() needs to include
check_uaccess. This is already the case for put_user(), so just make
__put_user() an alias of put_user().

Signed-off-by: Julien Thierry <julien.thierry@arm.com>

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

---
 arch/arm/include/asm/uaccess.h | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

-- 
2.21.0.rc0.269.g1a574e7a288b

Patch

diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 94b1bf53b820..7f96a942d9a0 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -407,6 +407,14 @@  do {									\
 	__pu_err;							\
 })
 
+#ifdef CONFIG_CPU_SPECTRE
+/*
+ * When mitigating Spectre variant 1.1, all accessors need to include
+ * verification of the address space.
+ */
+#define __put_user(x, ptr) put_user(x, ptr)
+
+#else
 #define __put_user(x, ptr)						\
 ({									\
 	long __pu_err = 0;						\
@@ -414,12 +422,6 @@  do {									\
 	__pu_err;							\
 })
 
-#define __put_user_error(x, ptr, err)					\
-({									\
-	__put_user_switch((x), (ptr), (err), __put_user_nocheck);	\
-	(void) 0;							\
-})
-
 #define __put_user_nocheck(x, __pu_ptr, __err, __size)			\
 	do {								\
 		unsigned long __pu_addr = (unsigned long)__pu_ptr;	\
@@ -499,6 +501,7 @@  do {									\
 	: "r" (x), "i" (-EFAULT)				\
 	: "cc")
 
+#endif /* !CONFIG_CPU_SPECTRE */
 
 #ifdef CONFIG_MMU
 extern unsigned long __must_check