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csky: use generic strncpy/strnlen from_user 

Remove the csky implemenation of strncpy/strnlen and instead use the
generic versions.  The csky 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 c52801a774
commit 0cd1151886
3 changed files with 2 additions and 114 deletions
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2
arch/csky/Kconfig
View File

@ -35,6 +35,8 @@ config CSKY
select GENERIC_IRQ_MULTI_HANDLER
select GENERIC_SCHED_CLOCK
select GENERIC_SMP_IDLE_THREAD
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
select GENERIC_VDSO_32
select GENERIC_GETTIMEOFDAY

6
arch/csky/include/asm/uaccess.h
View File

@ -209,12 +209,6 @@ unsigned long raw_copy_to_user(void *to, const void *from, unsigned long n);
unsigned long __clear_user(void __user *to, unsigned long n);
#define __clear_user __clear_user
long strncpy_from_user(char *dst, const char *src, long count);
#define strncpy_from_user strncpy_from_user
long strnlen_user(const char *s, long n);
#define strnlen_user strnlen_user
#include <asm/segment.h>
#include <asm-generic/uaccess.h>

108
arch/csky/lib/usercopy.c
View File

@ -142,114 +142,6 @@ unsigned long raw_copy_to_user(void *to, const void *from,
}
EXPORT_SYMBOL(raw_copy_to_user);
/*
* __strncpy_from_user: - Copy a NUL terminated string from userspace,
* with less checking.
* @dst: Destination address, in kernel space. This buffer must be at
* least @count bytes long.
* @src: Source address, in user space.
* @count: Maximum number of bytes to copy, including the trailing NUL.
*
* Copies a NUL-terminated string from userspace to kernel space.
* Caller must check the specified block with access_ok() before calling
* this function.
*
* On success, returns the length of the string (not including the trailing
* NUL).
*
* If access to userspace fails, returns -EFAULT (some data may have been
* copied).
*
* If @count is smaller than the length of the string, copies @count bytes
* and returns @count.
*/
long strncpy_from_user(char *dst, const char *src, long count)
{
long res, faultres;
int tmp;
if (!access_ok(s, 1))
return -EFAULT;
__asm__ __volatile__(
" cmpnei %3, 0 \n"
" bf 4f \n"
"1: cmpnei %1, 0 \n"
" bf 5f \n"
"2: ldb %4, (%3, 0) \n"
" stb %4, (%2, 0) \n"
" cmpnei %4, 0 \n"
" bf 3f \n"
" addi %3, 1 \n"
" addi %2, 1 \n"
" subi %1, 1 \n"
" br 1b \n"
"3: subu %0, %1 \n"
" br 5f \n"
"4: mov %0, %5 \n"
" br 5f \n"
".section __ex_table, \"a\" \n"
".align 2 \n"
".long 2b, 4b \n"
".previous \n"
"5: \n"
: "=r"(res), "=r"(count), "=r"(dst),
"=r"(src), "=r"(tmp), "=r"(faultres)
: "5"(-EFAULT), "0"(count), "1"(count),
"2"(dst), "3"(src)
: "memory");
return res;
}
EXPORT_SYMBOL(strncpy_from_user);
/*
* strnlen_user: - Get the size of a string in user space.
* @str: The string to measure.
* @n: The maximum valid length
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
* If the string is too long, returns a value greater than @n.
*/
long strnlen_user(const char *s, long n)
{
unsigned long res, tmp;
if (!access_ok(s, 1))
return -EFAULT;
__asm__ __volatile__(
" cmpnei %1, 0 \n"
" bf 3f \n"
"1: cmpnei %0, 0 \n"
" bf 3f \n"
"2: ldb %3, (%1, 0) \n"
" cmpnei %3, 0 \n"
" bf 3f \n"
" subi %0, 1 \n"
" addi %1, 1 \n"
" br 1b \n"
"3: subu %2, %0 \n"
" addi %2, 1 \n"
" br 5f \n"
"4: movi %0, 0 \n"
" br 5f \n"
".section __ex_table, \"a\" \n"
".align 2 \n"
".long 2b, 4b \n"
".previous \n"
"5: \n"
: "=r"(n), "=r"(s), "=r"(res), "=r"(tmp)
: "0"(n), "1"(s), "2"(n)
: "memory");
return res;
}
EXPORT_SYMBOL(strnlen_user);
/*
* __clear_user: - Zero a block of memory in user space, with less checking.
* @to: Destination address, in user space.