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newlib: libc: strlen M-profile PACBTI-enablement 

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
This commit is contained in:
Victor L. Do Nascimento 2022-12-21 11:22:36 +00:00 committed by Richard Earnshaw
parent ebd922e77a
commit 5582536896
2 changed files with 25 additions and 6 deletions
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17
newlib/libc/machine/arm/strlen-armv7.S
View File

@ -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

14
newlib/libc/machine/arm/strlen-thumb2-Os.S
View File

@ -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