ARM: 7527/1: uaccess: explicitly check __user pointer when !CPU_USE_DOMAINS
The {get,put}_user macros don't perform range checking on the provided
__user address when !CPU_HAS_DOMAINS.
This patch reworks the out-of-line assembly accessors to check the user
address against a specified limit, returning -EFAULT if is is out of
range.
[will: changed get_user register allocation to match put_user]
[rmk: fixed building on older ARM architectures]
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King
parent
2b2040af0b
commit
8404663f81
@ -320,4 +320,12 @@
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.size \name , . - \name
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.endm
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.macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req
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#ifndef CONFIG_CPU_USE_DOMAINS
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adds \tmp, \addr, #\size - 1
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sbcccs \tmp, \tmp, \limit
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bcs \bad
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#endif
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.endm
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#endif /* __ASM_ASSEMBLER_H__ */
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@ -101,28 +101,39 @@ extern int __get_user_1(void *);
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extern int __get_user_2(void *);
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extern int __get_user_4(void *);
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#define __get_user_x(__r2,__p,__e,__s,__i...) \
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#define __GUP_CLOBBER_1 "lr", "cc"
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#ifdef CONFIG_CPU_USE_DOMAINS
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#define __GUP_CLOBBER_2 "ip", "lr", "cc"
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#else
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#define __GUP_CLOBBER_2 "lr", "cc"
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#endif
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#define __GUP_CLOBBER_4 "lr", "cc"
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#define __get_user_x(__r2,__p,__e,__l,__s) \
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__asm__ __volatile__ ( \
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__asmeq("%0", "r0") __asmeq("%1", "r2") \
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__asmeq("%3", "r1") \
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"bl __get_user_" #__s \
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: "=&r" (__e), "=r" (__r2) \
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: "0" (__p) \
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: __i, "cc")
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: "0" (__p), "r" (__l) \
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: __GUP_CLOBBER_##__s)
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#define get_user(x,p) \
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({ \
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unsigned long __limit = current_thread_info()->addr_limit - 1; \
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register const typeof(*(p)) __user *__p asm("r0") = (p);\
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register unsigned long __r2 asm("r2"); \
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register unsigned long __l asm("r1") = __limit; \
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register int __e asm("r0"); \
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switch (sizeof(*(__p))) { \
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case 1: \
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__get_user_x(__r2, __p, __e, 1, "lr"); \
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break; \
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__get_user_x(__r2, __p, __e, __l, 1); \
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break; \
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case 2: \
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__get_user_x(__r2, __p, __e, 2, "r3", "lr"); \
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__get_user_x(__r2, __p, __e, __l, 2); \
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break; \
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case 4: \
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__get_user_x(__r2, __p, __e, 4, "lr"); \
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__get_user_x(__r2, __p, __e, __l, 4); \
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break; \
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default: __e = __get_user_bad(); break; \
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} \
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@ -135,31 +146,34 @@ extern int __put_user_2(void *, unsigned int);
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extern int __put_user_4(void *, unsigned int);
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extern int __put_user_8(void *, unsigned long long);
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#define __put_user_x(__r2,__p,__e,__s) \
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#define __put_user_x(__r2,__p,__e,__l,__s) \
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__asm__ __volatile__ ( \
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__asmeq("%0", "r0") __asmeq("%2", "r2") \
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__asmeq("%3", "r1") \
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"bl __put_user_" #__s \
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: "=&r" (__e) \
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: "0" (__p), "r" (__r2) \
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: "0" (__p), "r" (__r2), "r" (__l) \
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: "ip", "lr", "cc")
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#define put_user(x,p) \
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({ \
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unsigned long __limit = current_thread_info()->addr_limit - 1; \
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register const typeof(*(p)) __r2 asm("r2") = (x); \
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register const typeof(*(p)) __user *__p asm("r0") = (p);\
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register unsigned long __l asm("r1") = __limit; \
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register int __e asm("r0"); \
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switch (sizeof(*(__p))) { \
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case 1: \
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__put_user_x(__r2, __p, __e, 1); \
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__put_user_x(__r2, __p, __e, __l, 1); \
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break; \
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case 2: \
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__put_user_x(__r2, __p, __e, 2); \
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__put_user_x(__r2, __p, __e, __l, 2); \
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break; \
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case 4: \
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__put_user_x(__r2, __p, __e, 4); \
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__put_user_x(__r2, __p, __e, __l, 4); \
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break; \
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case 8: \
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__put_user_x(__r2, __p, __e, 8); \
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__put_user_x(__r2, __p, __e, __l, 8); \
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break; \
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default: __e = __put_user_bad(); break; \
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} \
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@ -16,8 +16,9 @@
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* __get_user_X
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*
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* Inputs: r0 contains the address
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* r1 contains the address limit, which must be preserved
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* Outputs: r0 is the error code
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* r2, r3 contains the zero-extended value
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* r2 contains the zero-extended value
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* lr corrupted
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*
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* No other registers must be altered. (see <asm/uaccess.h>
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@ -27,33 +28,39 @@
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* Note also that it is intended that __get_user_bad is not global.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/errno.h>
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#include <asm/domain.h>
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ENTRY(__get_user_1)
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check_uaccess r0, 1, r1, r2, __get_user_bad
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1: TUSER(ldrb) r2, [r0]
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mov r0, #0
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mov pc, lr
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ENDPROC(__get_user_1)
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ENTRY(__get_user_2)
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#ifdef CONFIG_THUMB2_KERNEL
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2: TUSER(ldrb) r2, [r0]
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3: TUSER(ldrb) r3, [r0, #1]
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check_uaccess r0, 2, r1, r2, __get_user_bad
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#ifdef CONFIG_CPU_USE_DOMAINS
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rb .req ip
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2: ldrbt r2, [r0], #1
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3: ldrbt rb, [r0], #0
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#else
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2: TUSER(ldrb) r2, [r0], #1
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3: TUSER(ldrb) r3, [r0]
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rb .req r0
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2: ldrb r2, [r0]
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3: ldrb rb, [r0, #1]
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#endif
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#ifndef __ARMEB__
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orr r2, r2, r3, lsl #8
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orr r2, r2, rb, lsl #8
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#else
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orr r2, r3, r2, lsl #8
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orr r2, rb, r2, lsl #8
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#endif
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mov r0, #0
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mov pc, lr
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ENDPROC(__get_user_2)
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ENTRY(__get_user_4)
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check_uaccess r0, 4, r1, r2, __get_user_bad
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4: TUSER(ldr) r2, [r0]
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mov r0, #0
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mov pc, lr
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@ -16,6 +16,7 @@
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* __put_user_X
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*
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* Inputs: r0 contains the address
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* r1 contains the address limit, which must be preserved
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* r2, r3 contains the value
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* Outputs: r0 is the error code
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* lr corrupted
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@ -27,16 +28,19 @@
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* Note also that it is intended that __put_user_bad is not global.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/errno.h>
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#include <asm/domain.h>
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ENTRY(__put_user_1)
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check_uaccess r0, 1, r1, ip, __put_user_bad
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1: TUSER(strb) r2, [r0]
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mov r0, #0
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mov pc, lr
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ENDPROC(__put_user_1)
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ENTRY(__put_user_2)
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check_uaccess r0, 2, r1, ip, __put_user_bad
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mov ip, r2, lsr #8
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#ifdef CONFIG_THUMB2_KERNEL
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#ifndef __ARMEB__
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@ -60,12 +64,14 @@ ENTRY(__put_user_2)
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ENDPROC(__put_user_2)
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ENTRY(__put_user_4)
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check_uaccess r0, 4, r1, ip, __put_user_bad
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4: TUSER(str) r2, [r0]
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mov r0, #0
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mov pc, lr
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ENDPROC(__put_user_4)
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ENTRY(__put_user_8)
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check_uaccess r0, 8, r1, ip, __put_user_bad
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#ifdef CONFIG_THUMB2_KERNEL
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5: TUSER(str) r2, [r0]
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6: TUSER(str) r3, [r0, #4]
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