[PATCH V3] arm: fix get_user BE behavior for target variable with size of 8 bytes
Victor Kamensky
victor.kamensky at linaro.org
Thu Aug 28 22:51:06 PDT 2014
e38361d 'ARM: 8091/2: add get_user() support for 8 byte types' commit
broke V7 BE get_user call when target var size is 64 bit, but '*ptr' size
is 32 bit or smaller. e38361d changed type of __r2 from 'register
unsigned long' to 'register typeof(x) __r2 asm("r2")' i.e before the change
even when target variable size was 64 bit, __r2 was still 32 bit.
But after e38361d commit, for target var of 64 bit size, __r2 became 64
bit and now it should occupy 2 registers r2, and r3. The issue in BE case
that r3 register is least significant word of __r2 and r2 register is most
significant word of __r2. But __get_user_4 still copies result into r2 (most
significant word of __r2). Subsequent code copies from __r2 into x, but
for situation described it will pick up only garbage from r3 register.
Special __get_user_64t_(124) functions are introduced. They are similar to
corresponding __get_user_(124) function but result stored in r3 register
(lsw in case of 64 bit __r2 in BE image). Those function are used by
get_user macro in case of BE and target var size is 64bit.
Also changed __get_user_lo8 name into __get_user_32t_8 to get consistent
naming accross all cases.
Signed-off-by: Victor Kamensky <victor.kamensky at linaro.org>
Suggested-by: Daniel Thompson <daniel.thompson at linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson at linaro.org>
---
arch/arm/include/asm/uaccess.h | 48 ++++++++++++++++++++++++++++++++++--------
arch/arm/lib/getuser.S | 38 +++++++++++++++++++++++++++++++--
2 files changed, 75 insertions(+), 11 deletions(-)
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index a4cd7af..4767eb9 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -107,8 +107,11 @@ static inline void set_fs(mm_segment_t fs)
extern int __get_user_1(void *);
extern int __get_user_2(void *);
extern int __get_user_4(void *);
-extern int __get_user_lo8(void *);
+extern int __get_user_32t_8(void *);
extern int __get_user_8(void *);
+extern int __get_user_64t_1(void *);
+extern int __get_user_64t_2(void *);
+extern int __get_user_64t_4(void *);
#define __GUP_CLOBBER_1 "lr", "cc"
#ifdef CONFIG_CPU_USE_DOMAINS
@@ -117,7 +120,7 @@ extern int __get_user_8(void *);
#define __GUP_CLOBBER_2 "lr", "cc"
#endif
#define __GUP_CLOBBER_4 "lr", "cc"
-#define __GUP_CLOBBER_lo8 "lr", "cc"
+#define __GUP_CLOBBER_32t_8 "lr", "cc"
#define __GUP_CLOBBER_8 "lr", "cc"
#define __get_user_x(__r2,__p,__e,__l,__s) \
@@ -131,12 +134,30 @@ extern int __get_user_8(void *);
/* narrowing a double-word get into a single 32bit word register: */
#ifdef __ARMEB__
-#define __get_user_xb(__r2, __p, __e, __l, __s) \
- __get_user_x(__r2, __p, __e, __l, lo8)
+#define __get_user_x_32t(__r2, __p, __e, __l, __s) \
+ __get_user_x(__r2, __p, __e, __l, 32t_8)
#else
-#define __get_user_xb __get_user_x
+#define __get_user_x_32t __get_user_x
#endif
+/*
+ * storing result into proper least significant word of 64bit target var,
+ * different only for big endian case where 64 bit __r2 lsw is r3:
+ */
+#ifdef __ARMEB__
+#define __get_user_x_64t(__r2, __p, __e, __l, __s) \
+ __asm__ __volatile__ ( \
+ __asmeq("%0", "r0") __asmeq("%1", "r2") \
+ __asmeq("%3", "r1") \
+ "bl __get_user_64t_" #__s \
+ : "=&r" (__e), "=r" (__r2) \
+ : "0" (__p), "r" (__l) \
+ : __GUP_CLOBBER_##__s)
+#else
+#define __get_user_x_64t __get_user_x
+#endif
+
+
#define __get_user_check(x,p) \
({ \
unsigned long __limit = current_thread_info()->addr_limit - 1; \
@@ -146,17 +167,26 @@ extern int __get_user_8(void *);
register int __e asm("r0"); \
switch (sizeof(*(__p))) { \
case 1: \
- __get_user_x(__r2, __p, __e, __l, 1); \
+ if (sizeof((x)) >= 8) \
+ __get_user_x_64t(__r2, __p, __e, __l, 1); \
+ else \
+ __get_user_x(__r2, __p, __e, __l, 1); \
break; \
case 2: \
- __get_user_x(__r2, __p, __e, __l, 2); \
+ if (sizeof((x)) >= 8) \
+ __get_user_x_64t(__r2, __p, __e, __l, 2); \
+ else \
+ __get_user_x(__r2, __p, __e, __l, 2); \
break; \
case 4: \
- __get_user_x(__r2, __p, __e, __l, 4); \
+ if (sizeof((x)) >= 8) \
+ __get_user_x_64t(__r2, __p, __e, __l, 4); \
+ else \
+ __get_user_x(__r2, __p, __e, __l, 4); \
break; \
case 8: \
if (sizeof((x)) < 8) \
- __get_user_xb(__r2, __p, __e, __l, 4); \
+ __get_user_x_32t(__r2, __p, __e, __l, 4); \
else \
__get_user_x(__r2, __p, __e, __l, 8); \
break; \
diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S
index 9386000..8ecfd15 100644
--- a/arch/arm/lib/getuser.S
+++ b/arch/arm/lib/getuser.S
@@ -80,7 +80,7 @@ ENTRY(__get_user_8)
ENDPROC(__get_user_8)
#ifdef __ARMEB__
-ENTRY(__get_user_lo8)
+ENTRY(__get_user_32t_8)
check_uaccess r0, 8, r1, r2, __get_user_bad
#ifdef CONFIG_CPU_USE_DOMAINS
add r0, r0, #4
@@ -90,7 +90,37 @@ ENTRY(__get_user_lo8)
#endif
mov r0, #0
ret lr
-ENDPROC(__get_user_lo8)
+ENDPROC(__get_user_32t_8)
+
+ENTRY(__get_user_64t_1)
+ check_uaccess r0, 1, r1, r2, __get_user_bad8
+8: TUSER(ldrb) r3, [r0]
+ mov r0, #0
+ ret lr
+ENDPROC(__get_user_64t_1)
+
+ENTRY(__get_user_64t_2)
+ check_uaccess r0, 2, r1, r2, __get_user_bad8
+#ifdef CONFIG_CPU_USE_DOMAINS
+rb .req ip
+9: ldrbt r3, [r0], #1
+10: ldrbt rb, [r0], #0
+#else
+rb .req r0
+9: ldrb r3, [r0]
+10: ldrb rb, [r0, #1]
+#endif
+ orr r3, rb, r3, lsl #8
+ mov r0, #0
+ ret lr
+ENDPROC(__get_user_64t_2)
+
+ENTRY(__get_user_64t_4)
+ check_uaccess r0, 4, r1, r2, __get_user_bad8
+11: TUSER(ldr) r3, [r0]
+ mov r0, #0
+ ret lr
+ENDPROC(__get_user_64t_4)
#endif
__get_user_bad8:
@@ -111,5 +141,9 @@ ENDPROC(__get_user_bad8)
.long 6b, __get_user_bad8
#ifdef __ARMEB__
.long 7b, __get_user_bad
+ .long 8b, __get_user_bad8
+ .long 9b, __get_user_bad8
+ .long 10b, __get_user_bad8
+ .long 11b, __get_user_bad8
#endif
.popsection
--
1.8.1.4
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