[PATCH v4 3/8] newlib: libc: strlen M-profile PACBTI-enablement
Victor L. Do Nascimento
victor.donascimento@arm.com
Wed Oct 26 11:47:41 GMT 2022
Add function prologue/epilogue to conditionally add BTI landing pads
and/or PAC code generation & authentication instructions depending on
compilation flags.
This patch enables PACBTI for all relevant variants of strlen:
* Newlib for armv8.1-m.main+pacbti
* Newlib for armv8.1-m.main+pacbti+mve
* Newlib-nano
---
newlib/libc/machine/arm/strlen-armv7.S | 17 ++++++++++++++---
newlib/libc/machine/arm/strlen-thumb2-Os.S | 14 +++++++++++---
2 files changed, 25 insertions(+), 6 deletions(-)
diff --git a/newlib/libc/machine/arm/strlen-armv7.S b/newlib/libc/machine/arm/strlen-armv7.S
index f3dda0d60..27094040c 100644
--- a/newlib/libc/machine/arm/strlen-armv7.S
+++ b/newlib/libc/machine/arm/strlen-armv7.S
@@ -59,6 +59,7 @@
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
#include "acle-compat.h"
+#include "arm_asm.h"
.macro def_fn f p2align=0
.text
@@ -78,7 +79,11 @@
/* This code requires Thumb. */
#if __ARM_ARCH_PROFILE == 'M'
+#if __ARM_ARCH >= 8
+ /* keep config inherited from -march=. */
+#else
.arch armv7e-m
+#endif /* if __ARM_ARCH >= 8 */
#else
.arch armv6t2
#endif
@@ -100,8 +105,10 @@
#define tmp2 r5
def_fn strlen p2align=6
+ .fnstart
+ .cfi_startproc
+ prologue 4 5 push_ip=HAVE_PAC_LEAF
pld [srcin, #0]
- strd r4, r5, [sp, #-8]!
bic src, srcin, #7
mvn const_m1, #0
ands tmp1, srcin, #7 /* (8 - bytes) to alignment. */
@@ -151,6 +158,7 @@ def_fn strlen p2align=6
beq .Lloop_aligned
.Lnull_found:
+ .cfi_remember_state
cmp data1a, #0
itt eq
addeq result, result, #4
@@ -159,11 +167,11 @@ def_fn strlen p2align=6
rev data1a, data1a
#endif
clz data1a, data1a
- ldrd r4, r5, [sp], #8
add result, result, data1a, lsr #3 /* Bits -> Bytes. */
- bx lr
+ epilogue 4 5 push_ip=HAVE_PAC_LEAF
.Lmisaligned8:
+ .cfi_restore_state
ldrd data1a, data1b, [src]
and tmp2, tmp1, #3
rsb result, tmp1, #0
@@ -177,4 +185,7 @@ def_fn strlen p2align=6
movne data1a, const_m1
mov const_0, #0
b .Lstart_realigned
+ .cfi_endproc
+ .cantunwind
+ .fnend
.size strlen, . - strlen
diff --git a/newlib/libc/machine/arm/strlen-thumb2-Os.S b/newlib/libc/machine/arm/strlen-thumb2-Os.S
index 961f41a0a..a46db573c 100644
--- a/newlib/libc/machine/arm/strlen-thumb2-Os.S
+++ b/newlib/libc/machine/arm/strlen-thumb2-Os.S
@@ -25,6 +25,7 @@
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
#include "acle-compat.h"
+#include "arm_asm.h"
.macro def_fn f p2align=0
.text
@@ -33,8 +34,9 @@
.type \f, %function
\f:
.endm
-
-#if __ARM_ARCH_ISA_THUMB >= 2 && __ARM_ARCH >= 7
+#if __ARM_ARCH_PROFILE == 'M' && __ARM_ARCH >= 8
+ /* keep config inherited from -march=. */
+#elif __ARM_ARCH_ISA_THUMB >= 2 && __ARM_ARCH >= 7
.arch armv7
#else
.arch armv6t2
@@ -44,11 +46,17 @@
.syntax unified
def_fn strlen p2align=1
+ .fnstart
+ .cfi_startproc
+ prologue
mov r3, r0
1: ldrb.w r2, [r3], #1
cmp r2, #0
bne 1b
subs r0, r3, r0
subs r0, #1
- bx lr
+ epilogue
+ .cfi_endproc
+ .cantunwind
+ .fnend
.size strlen, . - strlen
--
2.36.1
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