From: Victor Do Nascimento <victor.donascimento@arm.com>
To: <newlib@sourceware.org>
Cc: <richard.earnshaw@arm.com>,
Victor Do Nascimento <victor.donascimento@arm.com>
Subject: [PATCH v2 4/8] newlib: libc: memchr M-profile PACBTI-enablement
Date: Wed, 3 Aug 2022 16:35:20 +0100 [thread overview]
Message-ID: <20220803153524.20631-5-victor.donascimento@arm.com> (raw)
In-Reply-To: <20220803153524.20631-1-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.
---
newlib/libc/machine/arm/memchr.S | 55 ++++++++++++++++++++++++++++----
1 file changed, 48 insertions(+), 7 deletions(-)
diff --git a/newlib/libc/machine/arm/memchr.S b/newlib/libc/machine/arm/memchr.S
index 1a4c6512c..6bdccb934 100644
--- a/newlib/libc/machine/arm/memchr.S
+++ b/newlib/libc/machine/arm/memchr.S
@@ -76,6 +76,7 @@
.syntax unified
#include "acle-compat.h"
+#include "pacbti.h"
@ NOTE: This ifdef MUST match the one in memchr-stub.c
#if defined (__ARM_NEON__) || defined (__ARM_NEON)
@@ -267,10 +268,14 @@ memchr:
#elif __ARM_ARCH_ISA_THUMB >= 2 && defined (__ARM_FEATURE_DSP)
#if __ARM_ARCH_PROFILE == 'M'
- .arch armv7e-m
+#if __ARM_ARCH >= 8
+ /* keep config inherited from -march=. */
#else
- .arch armv6t2
-#endif
+ .arch armv7e-m
+#endif /* __ARM_ARCH >= 8 */
+#else
+ .arch armv6t2
+#endif /* __ARM_ARCH_PROFILE == 'M' */
@ this lets us check a flag in a 00/ff byte easily in either endianness
#ifdef __ARMEB__
@@ -287,11 +292,14 @@ memchr:
.p2align 4,,15
.global memchr
.type memchr,%function
+ .fnstart
+ .cfi_startproc
memchr:
@ r0 = start of memory to scan
@ r1 = character to look for
@ r2 = length
@ returns r0 = pointer to character or NULL if not found
+ pacbti_prologue
and r1,r1,#0xff @ Don't trust the caller to pass a char
cmp r2,#16 @ If short don't bother with anything clever
@@ -313,6 +321,19 @@ memchr:
10:
@ We are aligned, we know we have at least 8 bytes to work with
push {r4,r5,r6,r7}
+ .save {r4-r7}
+ .cfi_adjust_cfa_offset 16
+#if __HAVE_PAC_LEAF
+ .cfi_offset 4, -20
+ .cfi_offset 5, -16
+ .cfi_offset 6, -12
+ .cfi_offset 7, -8
+#else
+ .cfi_offset 4, -16
+ .cfi_offset 5, -12
+ .cfi_offset 6, -8
+ .cfi_offset 7, -4
+#endif /* __HAVE_PAC_LEAF*/
orr r1, r1, r1, lsl #8 @ expand the match word across all bytes
orr r1, r1, r1, lsl #16
bic r4, r2, #7 @ Number of double words to work with * 8
@@ -334,6 +355,11 @@ memchr:
bne 15b @ (Flags from the subs above)
pop {r4,r5,r6,r7}
+ .cfi_restore 7
+ .cfi_restore 6
+ .cfi_restore 5
+ .cfi_restore 4
+ .cfi_adjust_cfa_offset -16
and r1,r1,#0xff @ r1 back to a single character
and r2,r2,#7 @ Leave the count remaining as the number
@ after the double words have been done
@@ -350,11 +376,11 @@ memchr:
40:
movs r0,#0 @ not found
- bx lr
+ pacbti_epilogue
50:
subs r0,r0,#1 @ found
- bx lr
+ pacbti_epilogue
60: @ We're here because the fast path found a hit
@ now we have to track down exactly which word it was
@@ -378,9 +404,24 @@ memchr:
addeq r0,r0,#1
61:
- pop {r4,r5,r6,r7}
subs r0,r0,#1
- bx lr
+#if __HAVE_PAC_LEAF
+ pop {r4,r5,r6,r7,ip}
+ .cfi_restore 143
+#else
+ pop {r4,r5,r6,r7}
+#endif /* __HAVE_PAC_LEAF*/
+ .cfi_restore 7
+ .cfi_restore 6
+ .cfi_restore 5
+ .cfi_restore 4
+ .cfi_def_cfa_offset 0
+#if __HAVE_PAC_LEAF
+ aut ip, lr, sp
+#endif /* __HAVE_PAC_LEAF*/
+ bx lr
+ .cfi_endproc
+ .fnend
#else
/* Defined in memchr-stub.c. */
#endif
--
2.36.1
next prev parent reply other threads:[~2022-08-03 15:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-03 15:35 [PATCH v2 0/8] Implement assembly cortex-M PACBTI functionality Victor Do Nascimento
2022-08-03 15:35 ` [PATCH v2 1/8] newlib: libc: define M-profile PACBTI-enablement macros Victor Do Nascimento
2022-08-04 15:19 ` Richard Earnshaw
2022-08-05 9:21 ` Victor L. Do Nascimento
2022-08-16 16:11 ` Victor L. Do Nascimento
2022-08-18 16:28 ` Victor L. Do Nascimento
2022-08-03 15:35 ` [PATCH v2 2/8] newlib: libc: strcmp M-profile PACBTI-enablement Victor Do Nascimento
2022-08-04 15:48 ` Richard Earnshaw
2022-08-05 10:51 ` Victor L. Do Nascimento
2022-08-05 14:34 ` Richard Earnshaw
2022-08-05 14:58 ` Victor L. Do Nascimento
2022-08-05 15:15 ` Richard Earnshaw
2022-08-03 15:35 ` [PATCH v2 3/8] newlib: libc: strlen " Victor Do Nascimento
2022-08-03 15:35 ` Victor Do Nascimento [this message]
2022-08-03 15:35 ` [PATCH v2 5/8] newlib: libc: memcpy " Victor Do Nascimento
2022-08-03 15:35 ` [PATCH v2 6/8] newlib: libc: setjmp/longjmp " Victor Do Nascimento
2022-08-03 15:35 ` [PATCH v2 7/8] newlib: libc: aeabi_memmove " Victor Do Nascimento
2022-08-03 15:35 ` [PATCH v2 8/8] newlib: libc: aeabi_memset " Victor Do Nascimento
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