From: Victor Do Nascimento <victor.donascimento@arm.com>
To: <newlib@sourceware.org>
Subject: [PATCH 3/8] newlib: libc: strlen M-profile PACBTI-enablement
Date: Tue, 5 Jul 2022 14:58:13 +0100 [thread overview]
Message-ID: <20220705135818.50088-4-victor.donascimento@arm.com> (raw)
In-Reply-To: <20220705135818.50088-1-victor.donascimento@arm.com>
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 | 52 ++++++++++++++++++++--
newlib/libc/machine/arm/strlen-stub.c | 9 ++++
newlib/libc/machine/arm/strlen-thumb2-Os.S | 13 ++++--
3 files changed, 67 insertions(+), 7 deletions(-)
diff --git a/newlib/libc/machine/arm/strlen-armv7.S b/newlib/libc/machine/arm/strlen-armv7.S
index f3dda0d60..18c8226d0 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 "pacbti.h"
.macro def_fn f p2align=0
.text
@@ -77,7 +78,9 @@
#endif
/* This code requires Thumb. */
-#if __ARM_ARCH_PROFILE == 'M'
+#if __ARM_ARCH_8M_MAIN__
+ /* keep config inherited from -march= */
+#elif __ARM_ARCH_PROFILE == 'M'
.arch armv7e-m
#else
.arch armv6t2
@@ -100,8 +103,34 @@
#define tmp2 r5
def_fn strlen p2align=6
+ .fnstart
+ .cfi_startproc
+ /* common pacbti_prologue macro from pacbti.h not used.
+ handwritten prologue saves one push instruction. */
+#if __ARM_FEATURE_PAC_DEFAULT
+#if __ARM_FEATURE_BTI_DEFAULT
+ pacbti ip, lr, sp
+#else
+ pac ip, lr, sp
+#endif /* __ARM_FEATURE_BTI_DEFAULT */
+ push {r4, r5, ip}
+ .save {r4, r5, ra_auth_code}
+ .cfi_def_cfa_offset 12
+ .cfi_offset 143, -4
+ .cfi_offset 5, -8
+ .cfi_offset 4, -12
+
+#else
+#if __ARM_FEATURE_BTI_DEFAULT
+ bti
+#endif /* __ARM_FEATURE_BTI_DEFAULT */
+ push {r4, r5}
+ .save {r4, r5}
+ .cfi_def_cfa_offset 8
+ .cfi_offset 5, -4
+ .cfi_offset 4, -8
+#endif /* __ARM_FEATURE_PAC_DEFAULT */
pld [srcin, #0]
- strd r4, r5, [sp, #-8]!
bic src, srcin, #7
mvn const_m1, #0
ands tmp1, srcin, #7 /* (8 - bytes) to alignment. */
@@ -159,9 +188,22 @@ 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
+#if __ARM_FEATURE_PAC_DEFAULT
+ pop {r4, r5, ip}
+ .cfi_restore 4
+ .cfi_restore 5
+ .cfi_restore 143
+ .cfi_def_cfa_offset 0
+ aut ip, lr, sp
+#else
+ ldrd r4, r5, [sp], #8
+ .cfi_restore 4
+ .cfi_restore 5
+ .cfi_def_cfa_offset 0
+#endif /* __ARM_FEATURE_PAC_DEFAULT */
+ bx lr
+
.Lmisaligned8:
ldrd data1a, data1b, [src]
@@ -177,4 +219,6 @@ def_fn strlen p2align=6
movne data1a, const_m1
mov const_0, #0
b .Lstart_realigned
+ .cfi_endproc
+ .fnend
.size strlen, . - strlen
diff --git a/newlib/libc/machine/arm/strlen-stub.c b/newlib/libc/machine/arm/strlen-stub.c
index fc2daf16f..4a0bb8cbb 100644
--- a/newlib/libc/machine/arm/strlen-stub.c
+++ b/newlib/libc/machine/arm/strlen-stub.c
@@ -58,6 +58,11 @@ strlen (const char* str)
"data .req r3\n\t"
"addr .req r1\n\t"
+#ifdef __ARM_FEATURE_PAC_DEFAULT
+ "pac ip, lr, sp\n\t"
+ "str ip, [sp, #-4]!\n\t"
+#endif
+
#ifdef _ISA_ARM_7
"pld [r0]\n\t"
#endif
@@ -167,6 +172,10 @@ strlen (const char* str)
"it ne\n\t"
"addne len, len, #1\n\t"
# endif
+#endif
+#ifdef __ARM_FEATURE_PAC_DEFAULT
+ "ldr ip, [sp], #4\n\t"
+ "aut ip, lr, sp\n\t"
#endif
"bx lr\n\t");
}
diff --git a/newlib/libc/machine/arm/strlen-thumb2-Os.S b/newlib/libc/machine/arm/strlen-thumb2-Os.S
index 961f41a0a..823b0310e 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 "pacbti.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_8M_MAIN__
+ /* keep config inherited from -march= */
+#elif __ARM_ARCH_ISA_THUMB >= 2 && __ARM_ARCH >= 7
.arch armv7
#else
.arch armv6t2
@@ -44,11 +46,16 @@
.syntax unified
def_fn strlen p2align=1
+ .fnstart
+ .cfi_startproc
+ pacbti_prologue
mov r3, r0
1: ldrb.w r2, [r3], #1
cmp r2, #0
bne 1b
subs r0, r3, r0
subs r0, #1
- bx lr
+ pacbti_epilogue
+ .cfi_endproc
+ .fnend
.size strlen, . - strlen
--
2.36.1
next prev parent reply other threads:[~2022-07-05 13:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 13:58 [PATCH 0/8] Implement assembly cortex-M PACBTI functionality Victor Do Nascimento
2022-07-05 13:58 ` [PATCH 1/8] newlib: libc: define M-profile PACBTI-enablement macros Victor Do Nascimento
2022-07-05 13:58 ` [PATCH 2/8] newlib: libc: strcmp M-profile PACBTI-enablement Victor Do Nascimento
2022-07-05 13:58 ` Victor Do Nascimento [this message]
2022-07-05 15:39 ` [PATCH 3/8] newlib: libc: strlen " Richard Earnshaw
2022-07-05 16:30 ` Victor L. Do Nascimento
2022-07-06 9:07 ` Richard Earnshaw
2022-07-05 13:58 ` [PATCH 4/8] newlib: libc: memchr " Victor Do Nascimento
2022-07-05 13:58 ` [PATCH 5/8] newlib: libc: memcpy " Victor Do Nascimento
2022-07-05 13:58 ` [PATCH 6/8] newlib: libc: setjmp/longjmp " Victor Do Nascimento
2022-07-05 13:58 ` [PATCH 7/8] newlib: libc: aeabi_memmove " Victor Do Nascimento
2022-07-05 13:58 ` [PATCH 8/8] newlib: libc: aeabi_memset " Victor Do Nascimento
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