powerpc: Remove arch-specific strncpy() implementation

strncpy() has no remaining callers in the kernel[1]. Remove the
powerpc-specific assembly implementation from both the kernel
(arch/powerpc/lib/string.S) and the boot wrapper
(arch/powerpc/boot/string.S), along with the __HAVE_ARCH_STRNCPY
define and declaration, falling back to the generic version in
lib/string.c.

The boot wrapper's strncpy had no callers in arch/powerpc/boot/.

Link: https://github.com/KSPP/linux/issues/90 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
This commit is contained in:
Kees Cook 2026-03-23 01:17:19 +00:00
parent ad3242a9ac
commit 7eda356658
4 changed files with 0 additions and 38 deletions

View File

@ -18,19 +18,6 @@ strcpy:
bne 1b
blr
.globl strncpy
strncpy:
cmpwi 0,r5,0
beqlr
mtctr r5
addi r6,r3,-1
addi r4,r4,-1
1: lbzu r0,1(r4)
cmpwi 0,r0,0
stbu r0,1(r6)
bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */
blr
.globl strcat
strcat:
addi r5,r3,-1

View File

@ -4,7 +4,6 @@
#include <stddef.h>
extern char *strcpy(char *dest, const char *src);
extern char *strncpy(char *dest, const char *src, size_t n);
extern char *strcat(char *dest, const char *src);
extern char *strchr(const char *s, int c);
extern char *strrchr(const char *s, int c);

View File

@ -5,7 +5,6 @@
#ifdef __KERNEL__
#ifndef CONFIG_KASAN
#define __HAVE_ARCH_STRNCPY
#define __HAVE_ARCH_STRNCMP
#define __HAVE_ARCH_MEMCHR
#define __HAVE_ARCH_MEMCMP
@ -18,7 +17,6 @@
#define __HAVE_ARCH_MEMCPY_FLUSHCACHE
extern char * strcpy(char *,const char *);
extern char * strncpy(char *,const char *, __kernel_size_t);
extern __kernel_size_t strlen(const char *);
extern int strcmp(const char *,const char *);
extern int strncmp(const char *, const char *, __kernel_size_t);

View File

@ -10,28 +10,6 @@
.text
/* This clears out any unused part of the destination buffer,
just as the libc version does. -- paulus */
_GLOBAL(strncpy)
PPC_LCMPI 0,r5,0
beqlr
mtctr r5
addi r6,r3,-1
addi r4,r4,-1
.balign IFETCH_ALIGN_BYTES
1: lbzu r0,1(r4)
cmpwi 0,r0,0
stbu r0,1(r6)
bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */
bnelr /* if we didn't hit a null char, we're done */
mfctr r5
PPC_LCMPI 0,r5,0 /* any space left in destination buffer? */
beqlr /* we know r0 == 0 here */
2: stbu r0,1(r6) /* clear it out if so */
bdnz 2b
blr
EXPORT_SYMBOL(strncpy)
_GLOBAL(strncmp)
PPC_LCMPI 0,r5,0
beq- 2f