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authorRussell King <rmk+kernel@armlinux.org.uk>2018-07-09 15:22:45 +0100
committerDavid A. Long <dave.long@linaro.org>2018-10-30 23:23:46 -0400
commit142fee8a5498ccd0a377d20c5072b7dc9a2c359b (patch)
treee078bb9c54fa0593613d761bd68b0d5818ab7c36
parent0b8c16eeb3adc7279a22597913abec188e7f741a (diff)
downloadlinux-linaro-stable-142fee8a5498ccd0a377d20c5072b7dc9a2c359b.tar.gz
ARM: use __inttype() in get_user()
Commit d09fbb327d670737ab40fd8bbb0765ae06b8b739 upstream. Borrow the x86 implementation of __inttype() to use in get_user() to select an integer type suitable to temporarily hold the result value. This is necessary to avoid propagating the volatile nature of the result argument, which can cause the following warning: lib/iov_iter.c:413:5: warning: optimization may eliminate reads and/or writes to register variables [-Wvolatile-register-var] Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: David A. Long <dave.long@linaro.org>
-rw-r--r--arch/arm/include/asm/uaccess.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index cd8b589111ba..968b50063431 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -123,6 +123,13 @@ static inline void set_fs(mm_segment_t fs)
flag; })
/*
+ * This is a type: either unsigned long, if the argument fits into
+ * that type, or otherwise unsigned long long.
+ */
+#define __inttype(x) \
+ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
+
+/*
* Single-value transfer routines. They automatically use the right
* size if we just have the right pointer type. Note that the functions
* which read from user space (*get_*) need to take care not to leak
@@ -191,7 +198,7 @@ extern int __get_user_64t_4(void *);
({ \
unsigned long __limit = current_thread_info()->addr_limit - 1; \
register const typeof(*(p)) __user *__p asm("r0") = (p);\
- register typeof(x) __r2 asm("r2"); \
+ register __inttype(x) __r2 asm("r2"); \
register unsigned long __l asm("r1") = __limit; \
register int __e asm("r0"); \
unsigned int __ua_flags = uaccess_save_and_enable(); \