diff options
| author | Pavel Kozlov <pavel.kozlov@synopsys.com> | 2023-11-09 15:04:29 +0400 |
|---|---|---|
| committer | Waldemar Brodkorb <wbx@openadk.org> | 2023-11-10 16:14:20 +0100 |
| commit | 1762b04103e9b2c409649de1857a39867f15718f (patch) | |
| tree | c6065b406b652caf2800ca77741fb331ca0f8b33 | |
| parent | dfa72192f19f130d73e6587d0c3f7ef4e22c52c7 (diff) | |
arc: remove read ahead in asm strcmp code for ARCHS
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@synopsys.com>
| -rw-r--r-- | libc/string/arc/strcmp.S | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/libc/string/arc/strcmp.S b/libc/string/arc/strcmp.S index 3f64ac421..48d2d7ec1 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__ |