Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

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

arch/powerpc/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/powerpc/include/asm/uaccess.h

+5 −36
Original line number Diff line number Diff line
@@ -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__ */

arch/powerpc/include/asm/word-at-a-time.h

0 → 100644
+41 −0
Original line number Diff line number Diff line 
#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 */

arch/powerpc/kernel/ppc_ksyms.c

+0 −2
Original line number Diff line number Diff line
@@ -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)

arch/powerpc/lib/string.S

+0 −45
Original line number Diff line number Diff line
@@ -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