From: Will Newton <will.newton@linaro.org>
To: libc-ports@sourceware.org
Cc: patches@linaro.org
Subject: [PATCH] ARM: Add SystemTap probes to longjmp and setjmp.
Date: Mon, 27 Jan 2014 09:37:00 -0000 [thread overview]
Message-ID: <1390815426-10792-1-git-send-email-will.newton@linaro.org> (raw)
Now the ARM port implements pointer encryption for jmpbufs, gdb needs
a SystemTap probe point in longjmp to determine the target PC of
a call to longjmp. This patch implements the probe point in longjmp
and a similar probe point in setjmp.
In order to have all the appropriate registers available to pass to the
probe this reorders the layout of jmpbuf, putting the sp and lr registers
at the start rather than the end.
Tested on armv7, no new failures in the glibc testsuite and confirmed
that this fixes the gdb.base/longjmp.exp failures in the gdb testsuite.
ports/ChangeLog.arm:
2014-01-27 Will Newton <will.newton@linaro.org>
* sysdeps/arm/__longjmp.S: Include stap-probe.h.
(__longjmp): Restore sp and lr before restoring callee
saved registers. Add longjmp SystemTap probe point.
* sysdeps/arm/include/bits/setjmp.h (__JMP_BUF_SP):
Define to zero to match jmpbuf layout.
* sysdeps/arm/setjmp.S: Include stap-probe.h.
(__sigsetjmp): Save sp and lr before saving callee
saved registers. Add setjmp SystemTap probe point.
---
ports/sysdeps/arm/__longjmp.S | 21 ++++++++++++++-------
ports/sysdeps/arm/include/bits/setjmp.h | 2 +-
ports/sysdeps/arm/setjmp.S | 12 +++++++++---
3 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/ports/sysdeps/arm/__longjmp.S b/ports/sysdeps/arm/__longjmp.S
index 27c57a1..ad5fa9f 100644
--- a/ports/sysdeps/arm/__longjmp.S
+++ b/ports/sysdeps/arm/__longjmp.S
@@ -17,6 +17,7 @@
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
+#include <stap-probe.h>
#include <bits/setjmp.h>
#include <rtld-global-offsets.h>
#include <arm-features.h>
@@ -25,24 +26,21 @@
ENTRY (__longjmp)
mov ip, r0
- movs r0, r1 /* get the return value in place */
- it eq
- moveq r0, #1 /* can't let setjmp() return zero! */
#ifdef CHECK_SP
sfi_breg ip, \
- ldr r4, [\B, #32] /* jmpbuf's sp */
+ ldr r4, [\B] /* jmpbuf's sp */
cfi_undefined (r4)
#ifdef PTR_DEMANGLE
PTR_DEMANGLE (r4, r4, a3, a4)
#endif
CHECK_SP (r4)
#endif
- sfi_sp sfi_breg ip, \
- ldmia \B!, JMP_BUF_REGLIST
+
#ifdef PTR_DEMANGLE
ldr a4, [ip], #4
- PTR_DEMANGLE (a4, a4, a3, a2)
+ PTR_DEMANGLE (a4, a4, a3, r4)
+ cfi_undefined (r4)
mov sp, a4
ldr a4, [ip], #4
PTR_DEMANGLE2 (lr, a4, a3)
@@ -50,6 +48,11 @@ ENTRY (__longjmp)
ldr sp, [ip], #4
ldr lr, [ip], #4
#endif
+ /* longjmp probe expects longjmp first argument (4@r0), second
+ argument (-4@r1), and target address (4@r14), respectively. */
+ LIBC_PROBE (longjmp, 3, 4@r0, -4@r1, 4@r14)
+ sfi_sp sfi_breg ip, \
+ ldmia \B!, JMP_BUF_REGLIST
cfi_restore (v1)
cfi_restore (v2)
cfi_restore (v3)
@@ -61,6 +64,10 @@ ENTRY (__longjmp)
cfi_restore (sp)
cfi_restore (lr)
+ movs r0, r1 /* get the return value in place */
+ it eq
+ moveq r0, #1 /* can't let setjmp() return zero! */
+
#if !defined ARM_ASSUME_NO_IWMMXT || defined __SOFTFP__
# define NEED_HWCAP 1
#endif
diff --git a/ports/sysdeps/arm/include/bits/setjmp.h b/ports/sysdeps/arm/include/bits/setjmp.h
index 220dfe8..5877c1f 100644
--- a/ports/sysdeps/arm/include/bits/setjmp.h
+++ b/ports/sysdeps/arm/include/bits/setjmp.h
@@ -30,7 +30,7 @@
# define JMP_BUF_REGLIST {v1-v6, sl, fp}
/* Index of __jmp_buf where the sp register resides. */
-# define __JMP_BUF_SP 8
+# define __JMP_BUF_SP 0
#endif
#endif /* include/bits/setjmp.h */
diff --git a/ports/sysdeps/arm/setjmp.S b/ports/sysdeps/arm/setjmp.S
index b0b45ed..5e55ca5 100644
--- a/ports/sysdeps/arm/setjmp.S
+++ b/ports/sysdeps/arm/setjmp.S
@@ -17,6 +17,7 @@
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
+#include <stap-probe.h>
#include <bits/setjmp.h>
#include <rtld-global-offsets.h>
#include <arm-features.h>
@@ -27,9 +28,11 @@ ENTRY (__sigsetjmp)
#endif
mov ip, r0
- /* Save registers */
- sfi_breg ip, \
- stmia \B!, JMP_BUF_REGLIST
+ /* setjmp probe expects sigsetjmp first argument (4@r0), second
+ argument (-4@r1), and target address (4@r14), respectively. */
+ LIBC_PROBE (setjmp, 3, 4@r0, -4@r1, 4@r14)
+
+ /* Save sp and lr */
#ifdef PTR_MANGLE
mov a4, sp
PTR_MANGLE2 (a4, a4, a3)
@@ -40,6 +43,9 @@ ENTRY (__sigsetjmp)
str sp, [ip], #4
str lr, [ip], #4
#endif
+ /* Save registers */
+ sfi_breg ip, \
+ stmia \B!, JMP_BUF_REGLIST
#if !defined ARM_ASSUME_NO_IWMMXT || defined __SOFTFP__
# define NEED_HWCAP 1
--
1.8.1.4
next reply other threads:[~2014-01-27 9:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-27 9:37 Will Newton [this message]
2014-01-27 18:22 ` Joseph S. Myers
2014-01-27 20:51 ` Will Newton
2014-01-27 22:25 ` Joseph S. Myers
2014-01-28 21:35 ` Joseph S. Myers
2014-01-28 22:03 ` Roland McGrath
2014-01-29 10:15 ` Will Newton
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