[uclibc-ng-devel] [PATCH] arc: remove read ahead in asm strcmp code for ARCHS

From: Pavel Kozlov <pavel.kozlov(a)synopsys.com> Remove read ahead in the per-word compare loop as it can cause a segmentation fault in certain circumstances (when a string crosses a page boundary). For baremetal this relaxed approach is suitable but in Linux with MMU we should be more restrictive. Signed-off-by: Pavel Kozlov <pavel.kozlov(a)synopsys.com> --- libc/string/arc/strcmp.S | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/libc/string/arc/strcmp.S b/libc/string/arc/strcmp.S index 3f64ac421acc..48d2d7ec1d83 100644 --- a/libc/string/arc/strcmp.S +++ b/libc/string/arc/strcmp.S @@ -103,23 +103,21 @@ ENTRY(strcmp) brne r2, 0, @.Lcharloop ;;; s1 and s2 are word aligned - ld.ab r2, [r0, 4] mov_s r12, 0x01010101 ror r11, r12 .align 4 .LwordLoop: + ld.ab r2, [r0, 4] + sub r4, r2, r12 ld.ab r3, [r1, 4] ;; Detect NULL char in str1 - sub r4, r2, r12 - ld.ab r5, [r0, 4] bic r4, r4, r2 and r4, r4, r11 brne.d.nt r4, 0, .LfoundNULL ;; Check if the read locations are the same cmp r2, r3 - beq.d .LwordLoop - mov.eq r2, r5 + beq .LwordLoop ;; A match is found, spot it out #ifdef __LITTLE_ENDIAN__ -- 2.25.1