Create optimized __strcpy_chk/__strcat_chk.
This change pulls the memcpy code out into a new file so that the
__strcpy_chk and __strcat_chk can use it with an include.
The new versions of the two chk functions uses assembly versions
of strlen and memcpy to implement this check. This allows near
parity with the assembly versions of strcpy/strcat. It also means that
as memcpy implementations get faster, so do the chk functions.
Other included changes:
- Change all of the assembly labels to local labels. The other labels
confuse gdb and mess up backtracing.
- Add .cfi_startproc and .cfi_endproc directives so that gdb is not
confused when falling through from one function to another.
- Change all functions to use cfi directives since they are more powerful.
- Move the memcpy_chk fail code outside of the memcpy function definition
so that backtraces work properly.
- Preserve lr before the calls to __fortify_chk_fail so that the backtrace
actually works.
Testing:
- Ran the bionic unit tests. Verified all error messages in logs are set
correctly.
- Ran libc_test, replacing strcpy with __strcpy_chk and replacing
strcat with __strcat_chk.
- Ran the debugger on nexus10, nexus4, and old nexus7. Verified that the
backtrace is correct for all fortify check failures. Also verify that
when falling through from __memcpy_chk to memcpy that the backtrace is
still correct. Also verified the same for __memset_chk and bzero.
Verified the two different paths in the cortex-a9 memset routine that
save variables to the stack still show the backtrace properly.
Bug: 9293744
(cherry-picked from 2be91915dcecc956d14ff281db0c7d216ca98af2)
Change-Id: Ia407b74d3287d0b6af0139a90b6eb3bfaebf2155
diff --git a/libc/arch-arm/cortex-a9/bionic/memset.S b/libc/arch-arm/cortex-a9/bionic/memset.S
index d011430..bc25a3e 100644
--- a/libc/arch-arm/cortex-a9/bionic/memset.S
+++ b/libc/arch-arm/cortex-a9/bionic/memset.S
@@ -38,8 +38,14 @@
.fpu neon
ENTRY(__memset_chk)
+ .cfi_startproc
cmp r2, r3
- bls done
+ bls .L_done
+
+ // Preserve lr for backtrace.
+ push {lr}
+ .cfi_def_cfa_offset 4
+ .cfi_rel_offset lr, 0
ldr r0, error_message
ldr r1, error_code
@@ -51,24 +57,29 @@
error_message:
.word error_string-(1b+8)
+ .cfi_endproc
END(__memset_chk)
ENTRY(bzero)
+ .cfi_startproc
mov r2, r1
mov r1, #0
-done:
+.L_done:
// Fall through to memset...
+ .cfi_endproc
END(bzero)
/* memset() returns its first argument. */
ENTRY(memset)
+ .cfi_startproc
# The neon memset only wins for less than 132.
cmp r2, #132
bhi 11f
- .save {r0}
stmfd sp!, {r0}
+ .cfi_def_cfa_offset 4
+ .cfi_rel_offset r0, 0
vdup.8 q0, r1
@@ -106,8 +117,15 @@
* offset = (4-(src&3))&3 = -src & 3
*/
- .save {r0, r4-r7, lr}
stmfd sp!, {r0, r4-r7, lr}
+ .cfi_def_cfa_offset 24
+ .cfi_rel_offset r0, 0
+ .cfi_rel_offset r4, 4
+ .cfi_rel_offset r5, 8
+ .cfi_rel_offset r6, 12
+ .cfi_rel_offset r7, 16
+ .cfi_rel_offset lr, 20
+
rsb r3, r0, #0
ands r3, r3, #3
cmp r3, r2
@@ -169,6 +187,7 @@
strcsb r1, [r0]
ldmfd sp!, {r0, r4-r7, lr}
bx lr
+ .cfi_endproc
END(memset)
.data