Commit 1629372c authored by Paul Mackerras's avatar Paul Mackerras Committed by Linus Torvalds
Browse files

powerpc: Use the new generic strncpy_from_user() and strnlen_user()



This is much the same as for SPARC except that we can do the find_zero()
function more efficiently using the count-leading-zeroes instructions.
Tested on 32-bit and 64-bit PowerPC.
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 69ea6405
......@@ -135,6 +135,8 @@ config PPC
select GENERIC_CMOS_UPDATE
select GENERIC_TIME_VSYSCALL
select GENERIC_CLOCKEVENTS
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
config EARLY_PRINTK
bool
......
......@@ -40,6 +40,8 @@
#define segment_eq(a, b) ((a).seg == (b).seg)
#define user_addr_max() (get_fs().seg)
#ifdef __powerpc64__
/*
* This check is sufficient because there is a large enough
......@@ -453,42 +455,9 @@ static inline unsigned long clear_user(void __user *addr, unsigned long size)
return size;
}
extern int __strncpy_from_user(char *dst, const char __user *src, long count);
static inline long strncpy_from_user(char *dst, const char __user *src,
long count)
{
might_sleep();
if (likely(access_ok(VERIFY_READ, src, 1)))
return __strncpy_from_user(dst, src, count);
return -EFAULT;
}
/*
* Return the size of a string (including the ending 0)
*
* Return 0 for error
*/
extern int __strnlen_user(const char __user *str, long len, unsigned long top);
/*
* Returns the length of the string at str (including the null byte),
* or 0 if we hit a page we can't access,
* or something > len if we didn't find a null byte.
*
* The `top' parameter to __strnlen_user is to make sure that
* we can never overflow from the user area into kernel space.
*/
static inline int strnlen_user(const char __user *str, long len)
{
unsigned long top = current->thread.fs.seg;
if ((unsigned long)str > top)
return 0;
return __strnlen_user(str, len, top);
}
#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
extern long strncpy_from_user(char *dst, const char __user *src, long count);
extern __must_check long strlen_user(const char __user *str);
extern __must_check long strnlen_user(const char __user *str, long n);
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
......
#ifndef _ASM_WORD_AT_A_TIME_H
#define _ASM_WORD_AT_A_TIME_H
/*
* Word-at-a-time interfaces for PowerPC.
*/
#include <linux/kernel.h>
#include <asm/asm-compat.h>
struct word_at_a_time {
const unsigned long high_bits, low_bits;
};
#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
/* Bit set in the bytes that have a zero */
static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
{
unsigned long mask = (val & c->low_bits) + c->low_bits;
return ~(mask | rhs);
}
#define create_zero_mask(mask) (mask)
static inline long find_zero(unsigned long mask)
{
long leading_zero_bits;
asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask));
return leading_zero_bits >> 3;
}
static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
{
unsigned long rhs = val | c->low_bits;
*data = rhs;
return (val + c->high_bits) & ~rhs;
}
#endif /* _ASM_WORD_AT_A_TIME_H */
......@@ -85,8 +85,6 @@ EXPORT_SYMBOL(csum_tcpudp_magic);
EXPORT_SYMBOL(__copy_tofrom_user);
EXPORT_SYMBOL(__clear_user);
EXPORT_SYMBOL(__strncpy_from_user);
EXPORT_SYMBOL(__strnlen_user);
EXPORT_SYMBOL(copy_page);
#if defined(CONFIG_PCI) && defined(CONFIG_PPC32)
......
......@@ -160,48 +160,3 @@ _GLOBAL(__clear_user)
PPC_LONG 1b,91b
PPC_LONG 8b,92b
.text
_GLOBAL(__strncpy_from_user)
addi r6,r3,-1
addi r4,r4,-1
cmpwi 0,r5,0
beq 2f
mtctr r5
1: lbzu r0,1(r4)
cmpwi 0,r0,0
stbu r0,1(r6)
bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */
beq 3f
2: addi r6,r6,1
3: subf r3,r3,r6
blr
99: li r3,-EFAULT
blr
.section __ex_table,"a"
PPC_LONG 1b,99b
.text
/* r3 = str, r4 = len (> 0), r5 = top (highest addr) */
_GLOBAL(__strnlen_user)
addi r7,r3,-1
subf r6,r7,r5 /* top+1 - str */
cmplw 0,r4,r6
bge 0f
mr r6,r4
0: mtctr r6 /* ctr = min(len, top - str) */
1: lbzu r0,1(r7) /* get next byte */
cmpwi 0,r0,0
bdnzf 2,1b /* loop if --ctr != 0 && byte != 0 */
addi r7,r7,1
subf r3,r3,r7 /* number of bytes we have looked at */
beqlr /* return if we found a 0 byte */
cmpw 0,r3,r4 /* did we look at all len bytes? */
blt 99f /* if not, must have hit top */
addi r3,r4,1 /* return len + 1 to indicate no null found */
blr
99: li r3,0 /* bad address, return 0 */
blr
.section __ex_table,"a"
PPC_LONG 1b,99b
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