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microblaze: use generic strncpy/strnlen from_user

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Remove the microblaze implemenation of strncpy/strnlen and instead use
the generic versions.  The microblaze version is fairly slow because it
always does byte accesses even for aligned data, and it lacks a checks
for user_addr_max().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2020-01-16 15:58:41 +01:00
parent 0cd1151886
commit b26b181651
4 changed files with 6 additions and 108 deletions
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2
arch/microblaze/Kconfig
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@ -21,6 +21,8 @@ config MICROBLAZE
select GENERIC_IRQ_SHOW
select GENERIC_PCI_IOMAP
select GENERIC_SCHED_CLOCK
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select HAVE_ARCH_HASH
select HAVE_ARCH_KGDB
select HAVE_ARCH_SECCOMP

21
arch/microblaze/include/asm/uaccess.h
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@ -35,6 +35,7 @@
# define get_fs() (current_thread_info()->addr_limit)
# define set_fs(val) (current_thread_info()->addr_limit = (val))
# define user_addr_max() get_fs().seg
# define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
@ -296,28 +297,14 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
/*
* Copy a null terminated string from userspace.
*/
extern int __strncpy_user(char *to, const char __user *from, int len);
static inline long
strncpy_from_user(char *dst, const char __user *src, long count)
{
if (!access_ok(src, 1))
return -EFAULT;
return __strncpy_user(dst, src, count);
}
__must_check long strncpy_from_user(char *dst, const char __user *src,
long count);
/*
* Return the size of a string (including the ending 0)
*
* Return 0 on exception, a value greater than N if too long
*/
extern int __strnlen_user(const char __user *sstr, int len);
static inline long strnlen_user(const char __user *src, long n)
{
if (!access_ok(src, 1))
return 0;
return __strnlen_user(src, n);
}
__must_check long strnlen_user(const char __user *sstr, long len);
#endif /* _ASM_MICROBLAZE_UACCESS_H */

1
arch/microblaze/kernel/microblaze_ksyms.c
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@ -26,7 +26,6 @@ EXPORT_SYMBOL(_mcount);
* Assembly functions that may be used (directly or indirectly) by modules
*/
EXPORT_SYMBOL(__copy_tofrom_user);
EXPORT_SYMBOL(__strncpy_user);
#ifdef CONFIG_OPT_LIB_ASM
EXPORT_SYMBOL(memcpy);

90
arch/microblaze/lib/uaccess_old.S
View File

@ -12,96 +12,6 @@
#include <linux/linkage.h>
#include <asm/page.h>
/*
* int __strncpy_user(char *to, char *from, int len);
*
* Returns:
* -EFAULT for an exception
* len if we hit the buffer limit
* bytes copied
*/
.text
.globl __strncpy_user;
.type __strncpy_user, @function
.align 4;
__strncpy_user:
/*
* r5 - to
* r6 - from
* r7 - len
* r3 - temp count
* r4 - temp val
*/
beqid r7,3f
addik r3,r7,0 /* temp_count = len */
1:
lbu r4,r6,r0
beqid r4,2f
sb r4,r5,r0
addik r5,r5,1
addik r6,r6,1 /* delay slot */
addik r3,r3,-1
bnei r3,1b /* break on len */
2:
rsubk r3,r3,r7 /* temp_count = len - temp_count */
3:
rtsd r15,8
nop
.size __strncpy_user, . - __strncpy_user
.section .fixup, "ax"
.align 2
4:
brid 3b
addik r3,r0, -EFAULT
.section __ex_table, "a"
.word 1b,4b
/*
* int __strnlen_user(char __user *str, int maxlen);
*
* Returns:
* 0 on error
* maxlen + 1 if no NUL byte found within maxlen bytes
* size of the string (including NUL byte)
*/
.text
.globl __strnlen_user;
.type __strnlen_user, @function
.align 4;
__strnlen_user:
beqid r6,3f
addik r3,r6,0
1:
lbu r4,r5,r0
beqid r4,2f /* break on NUL */
addik r3,r3,-1 /* delay slot */
bneid r3,1b
addik r5,r5,1 /* delay slot */
addik r3,r3,-1 /* for break on len */
2:
rsubk r3,r3,r6
3:
rtsd r15,8
nop
.size __strnlen_user, . - __strnlen_user
.section .fixup,"ax"
4:
brid 3b
addk r3,r0,r0
.section __ex_table,"a"
.word 1b,4b
/* Loop unrolling for __copy_tofrom_user */
#define COPY(offset) \
1: lwi r4 , r6, 0x0000 + offset; \