xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

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

Browse Source 
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: Paul Mackerras <paulus@samba.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Paul Mackerras
2012-05-28 13:03:47 +10:00
committed by Linus Torvalds
parent 69ea640598
commit 1629372caa
5 changed files with 48 additions and 83 deletions
Download Patch File Download Diff File Expand all files Collapse all files

45
arch/powerpc/lib/string.S
View File

@@ -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