From: "Victor L. Do Nascimento" <victor.donascimento@arm.com>
To: <newlib@sourceware.org>
Cc: <Richard.Earnshaw@arm.com>
Subject: [PATCH v4 2/8] newlib: libc: strcmp M-profile PACBTI-enablement
Date: Wed, 26 Oct 2022 12:46:37 +0100 [thread overview]
Message-ID: <yw8j35balsde.fsf@arm.com> (raw)
In-Reply-To: <yw8jbkpylste.fsf@arm.com> (Victor L. Do Nascimento's message of "Wed, 26 Oct 2022 12:37:01 +0100")
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 strcmp:
* Newlib for armv8.1-m.main+pacbti
* Newlib for armv8.1-m.main+pacbti+mve
* Newlib-nano
---
newlib/libc/machine/arm/strcmp-arm-tiny.S | 8 ++++-
newlib/libc/machine/arm/strcmp-armv7.S | 44 +++++++++++++++--------
newlib/libc/machine/arm/strcmp-armv7m.S | 26 +++++++++-----
3 files changed, 54 insertions(+), 24 deletions(-)
diff --git a/newlib/libc/machine/arm/strcmp-arm-tiny.S b/newlib/libc/machine/arm/strcmp-arm-tiny.S
index 607a41daf..0bd2a2e6e 100644
--- a/newlib/libc/machine/arm/strcmp-arm-tiny.S
+++ b/newlib/libc/machine/arm/strcmp-arm-tiny.S
@@ -29,10 +29,14 @@
/* Tiny version of strcmp in ARM state. Used only when optimizing
for size. Also supports Thumb-2. */
+#include "arm_asm.h"
+
.syntax unified
def_fn strcmp
+ .fnstart
.cfi_sections .debug_frame
.cfi_startproc
+ prologue
1:
ldrb r2, [r0], #1
ldrb r3, [r1], #1
@@ -42,6 +46,8 @@ def_fn strcmp
beq 1b
2:
subs r0, r2, r3
- bx lr
+ epilogue
.cfi_endproc
+ .cantunwind
+ .fnend
.size strcmp, . - strcmp
diff --git a/newlib/libc/machine/arm/strcmp-armv7.S b/newlib/libc/machine/arm/strcmp-armv7.S
index 2f93bfb73..26ba579ae 100644
--- a/newlib/libc/machine/arm/strcmp-armv7.S
+++ b/newlib/libc/machine/arm/strcmp-armv7.S
@@ -45,6 +45,8 @@
.thumb
.syntax unified
+#include "arm_asm.h"
+
/* Parameters and result. */
#define src1 r0
#define src2 r1
@@ -91,8 +93,9 @@
ldrd r4, r5, [sp], #16
.cfi_restore 4
.cfi_restore 5
+ .cfi_adjust_cfa_offset -16
sub result, result, r1, lsr #24
- bx lr
+ epilogue push_ip=HAVE_PAC_LEAF
#else
/* To use the big-endian trick we'd have to reverse all three words.
that's slower than this approach. */
@@ -112,22 +115,30 @@
ldrd r4, r5, [sp], #16
.cfi_restore 4
.cfi_restore 5
+ .cfi_adjust_cfa_offset -16
sub result, result, r1
- bx lr
+ epilogue push_ip=HAVE_PAC_LEAF
#endif
.endm
+
.text
.p2align 5
+ .fnstart
+ .cfi_sections .debug_frame
+ .cfi_startproc
.Lstrcmp_start_addr:
#ifndef STRCMP_NO_PRECHECK
.Lfastpath_exit:
+ .cfi_remember_state
sub r0, r2, r3
- bx lr
+ epilogue push_ip=HAVE_PAC_LEAF
nop
#endif
def_fn strcmp
+ .cfi_restore_state
+ prologue push_ip=HAVE_PAC_LEAF
#ifndef STRCMP_NO_PRECHECK
ldrb r2, [src1]
ldrb r3, [src2]
@@ -136,16 +147,14 @@ def_fn strcmp
cmpcs r2, r3
bne .Lfastpath_exit
#endif
- .cfi_sections .debug_frame
- .cfi_startproc
strd r4, r5, [sp, #-16]!
- .cfi_def_cfa_offset 16
- .cfi_offset 4, -16
- .cfi_offset 5, -12
+ .cfi_adjust_cfa_offset 16
+ .cfi_rel_offset 4, 0
+ .cfi_rel_offset 5, 4
orr tmp1, src1, src2
strd r6, r7, [sp, #8]
- .cfi_offset 6, -8
- .cfi_offset 7, -4
+ .cfi_rel_offset 6, 8
+ .cfi_rel_offset 7, 12
mvn const_m1, #0
lsl r2, tmp1, #29
cbz r2, .Lloop_aligned8
@@ -270,7 +279,6 @@ def_fn strcmp
ldr data1, [src1], #4
beq .Laligned_m2
bcs .Laligned_m1
-
#ifdef STRCMP_NO_PRECHECK
ldrb data2, [src2, #1]
uxtb tmp1, data1, ror #BYTE1_OFFSET
@@ -314,7 +322,8 @@ def_fn strcmp
mov result, tmp1
ldr r4, [sp], #16
.cfi_restore 4
- bx lr
+ .cfi_adjust_cfa_offset -16
+ epilogue push_ip=HAVE_PAC_LEAF
#ifndef STRCMP_NO_PRECHECK
.Laligned_m1:
@@ -364,8 +373,9 @@ def_fn strcmp
/* R6/7 Not used in this sequence. */
.cfi_restore 6
.cfi_restore 7
+ .cfi_adjust_cfa_offset -16
neg result, result
- bx lr
+ epilogue push_ip=HAVE_PAC_LEAF
6:
.cfi_restore_state
@@ -441,7 +451,8 @@ def_fn strcmp
/* R6/7 not used in this sequence. */
.cfi_restore 6
.cfi_restore 7
- bx lr
+ .cfi_adjust_cfa_offset -16
+ epilogue push_ip=HAVE_PAC_LEAF
.Lstrcmp_tail:
.cfi_restore_state
@@ -463,7 +474,10 @@ def_fn strcmp
/* R6/7 not used in this sequence. */
.cfi_restore 6
.cfi_restore 7
+ .cfi_adjust_cfa_offset -16
sub result, result, data2, lsr #24
- bx lr
+ epilogue push_ip=HAVE_PAC_LEAF
.cfi_endproc
+ .cantunwind
+ .fnend
.size strcmp, . - .Lstrcmp_start_addr
diff --git a/newlib/libc/machine/arm/strcmp-armv7m.S b/newlib/libc/machine/arm/strcmp-armv7m.S
index cdb4912df..825b6e77f 100644
--- a/newlib/libc/machine/arm/strcmp-armv7m.S
+++ b/newlib/libc/machine/arm/strcmp-armv7m.S
@@ -29,6 +29,8 @@
/* Very similar to the generic code, but uses Thumb2 as implemented
in ARMv7-M. */
+#include "arm_asm.h"
+
/* Parameters and result. */
#define src1 r0
#define src2 r1
@@ -44,8 +46,10 @@
.thumb
.syntax unified
def_fn strcmp
+ .fnstart
.cfi_sections .debug_frame
.cfi_startproc
+ prologue push_ip=HAVE_PAC_LEAF
eor tmp1, src1, src2
tst tmp1, #3
/* Strings not at same byte offset from a word boundary. */
@@ -82,6 +86,7 @@ def_fn strcmp
ldreq data2, [src2], #4
beq 4b
2:
+ .cfi_remember_state
/* There's a zero or a different byte in the word */
S2HI result, data1, #24
S2LO data1, data1, #8
@@ -106,7 +111,7 @@ def_fn strcmp
lsrs result, result, #24
subs result, result, data2
#endif
- bx lr
+ epilogue push_ip=HAVE_PAC_LEAF
#if 0
@@ -205,8 +210,10 @@ def_fn strcmp
/* First of all, compare bytes until src1(sp1) is word-aligned. */
.Lstrcmp_unaligned:
+ .cfi_restore_state
tst src1, #3
beq 2f
+ .cfi_remember_state
ldrb data1, [src1], #1
ldrb data2, [src2], #1
cmp data1, #1
@@ -214,12 +221,13 @@ def_fn strcmp
cmpcs data1, data2
beq .Lstrcmp_unaligned
sub result, data1, data2
- bx lr
+ epilogue push_ip=HAVE_PAC_LEAF
2:
+ .cfi_restore_state
stmfd sp!, {r5}
- .cfi_def_cfa_offset 4
- .cfi_offset 5, -4
+ .cfi_adjust_cfa_offset 4
+ .cfi_rel_offset 5, 0
ldr data1, [src1], #4
and tmp2, src2, #3
@@ -355,8 +363,8 @@ def_fn strcmp
.cfi_remember_state
ldmfd sp!, {r5}
.cfi_restore 5
- .cfi_def_cfa_offset 0
- bx lr
+ .cfi_adjust_cfa_offset -4
+ epilogue push_ip=HAVE_PAC_LEAF
.Lstrcmp_tail:
.cfi_restore_state
@@ -372,7 +380,9 @@ def_fn strcmp
sub result, r2, result
ldmfd sp!, {r5}
.cfi_restore 5
- .cfi_def_cfa_offset 0
- bx lr
+ .cfi_adjust_cfa_offset -4
+ epilogue push_ip=HAVE_PAC_LEAF
.cfi_endproc
+ .cantunwind
+ .fnend
.size strcmp, . - strcmp
--
2.36.1
next prev parent reply other threads:[~2022-10-26 11:46 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-26 11:37 [PATCH v4 0/8] Implement assembly cortex-M PACBTI functionality Victor L. Do Nascimento
2022-10-26 11:45 ` [PATCH v4 1/8] newlib: libc: define M-profile PACBTI-enablement macros Victor L. Do Nascimento
2022-11-22 15:04 ` Richard Earnshaw
2022-10-26 11:46 ` Victor L. Do Nascimento [this message]
2022-11-22 15:04 ` [PATCH v4 2/8] newlib: libc: strcmp M-profile PACBTI-enablement Richard Earnshaw
2022-10-26 11:47 ` [PATCH v4 3/8] newlib: libc: strlen " Victor L. Do Nascimento
2022-11-22 15:20 ` Richard Earnshaw
2022-10-26 11:49 ` [PATCH v4 4/8] newlib: libc: memchr " Victor L. Do Nascimento
2022-11-22 15:33 ` Richard Earnshaw
2022-10-26 11:50 ` [PATCH v4 5/8] newlib: libc: memcpy " Victor L. Do Nascimento
2022-11-22 16:03 ` Richard Earnshaw
2022-10-26 11:51 ` [PATCH v4 6/8] newlib: libc: setjmp/longjmp " Victor L. Do Nascimento
2022-11-22 16:17 ` Richard Earnshaw
2022-10-26 11:52 ` [PATCH v4 7/8] newlib: libc: aeabi_memmove " Victor L. Do Nascimento
2022-11-22 16:18 ` Richard Earnshaw
2022-10-26 11:53 ` [PATCH v4 8/8] newlib: libc: aeabi_memset " Victor L. Do Nascimento
2022-11-22 16:19 ` Richard Earnshaw
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