ARM: Add SystemTap probes to longjmp and setjmp.

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, allowing them to be read and
written sequentially.

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.

ChangeLog:

2014-02-25  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 and longjmp_target
	SystemTap probe point.
	* sysdeps/arm/bits/setjmp.h (__jmp_buf): Update comment.
	* 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.
This commit is contained in:
Will Newton 2014-01-27 09:01:03 +00:00
parent 3ea0f74e1d
commit 80a56cc3ee
5 changed files with 62 additions and 31 deletions

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@ -1,3 +1,16 @@
2014-02-25 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 and longjmp_target
SystemTap probe point.
* sysdeps/arm/bits/setjmp.h (__jmp_buf): Update comment.
* 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.
2014-02-24 Stefan Liebler <stli@linux.vnet.ibm.com> 2014-02-24 Stefan Liebler <stli@linux.vnet.ibm.com>
* sysdeps/s390/fpu/libm-test-ulps: Regenerate. * sysdeps/s390/fpu/libm-test-ulps: Regenerate.

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@ -17,6 +17,7 @@
<http://www.gnu.org/licenses/>. */ <http://www.gnu.org/licenses/>. */
#include <sysdep.h> #include <sysdep.h>
#include <stap-probe.h>
#include <bits/setjmp.h> #include <bits/setjmp.h>
#include <rtld-global-offsets.h> #include <rtld-global-offsets.h>
#include <arm-features.h> #include <arm-features.h>
@ -25,31 +26,35 @@
ENTRY (__longjmp) ENTRY (__longjmp)
mov ip, r0 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 #ifdef CHECK_SP
sfi_breg ip, \ sfi_breg ip, \
ldr r4, [\B, #32] /* jmpbuf's sp */ ldr r4, [\B] /* jmpbuf's sp */
cfi_undefined (r4) cfi_undefined (r4)
#ifdef PTR_DEMANGLE #ifdef PTR_DEMANGLE
PTR_DEMANGLE (r4, r4, a3, a4) PTR_DEMANGLE (r4, r4, a3, a4)
#endif #endif
CHECK_SP (r4) CHECK_SP (r4)
#endif #endif
sfi_sp sfi_breg ip, \
ldmia \B!, JMP_BUF_REGLIST
#ifdef PTR_DEMANGLE #ifdef PTR_DEMANGLE
ldr a4, [ip], #4 ldr a4, [ip], #4
PTR_DEMANGLE (a4, a4, a3, a2) PTR_DEMANGLE (a4, a4, a3, r4)
mov sp, a4 cfi_undefined (r4)
ldr a4, [ip], #4 ldr r4, [ip], #4
PTR_DEMANGLE2 (lr, a4, a3) PTR_DEMANGLE2 (r4, r4, a3)
#else #else
ldr sp, [ip], #4 ldr a4, [ip], #4
ldr lr, [ip], #4 ldr r4, [ip], #4
cfi_undefined (r4)
#endif #endif
/* longjmp probe expects longjmp first argument (4@r0), second
argument (-4@r1), and target address (4@r4), respectively. */
LIBC_PROBE (longjmp, 3, 4@r0, -4@r1, 4@r4)
mov sp, a4
mov lr, r4
sfi_sp sfi_breg ip, \
ldmia \B!, JMP_BUF_REGLIST
cfi_restore (v1) cfi_restore (v1)
cfi_restore (v2) cfi_restore (v2)
cfi_restore (v3) cfi_restore (v3)
@ -67,27 +72,27 @@ ENTRY (__longjmp)
#ifdef NEED_HWCAP #ifdef NEED_HWCAP
# ifdef IS_IN_rtld # ifdef IS_IN_rtld
ldr a2, 1f ldr a4, 1f
ldr a3, .Lrtld_local_ro ldr a3, .Lrtld_local_ro
0: add a2, pc, a2 0: add a4, pc, a4
add a2, a2, a3 add a4, a4, a3
ldr a2, [a2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET] ldr a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
# else # else
# ifdef PIC # ifdef PIC
ldr a2, 1f ldr a4, 1f
ldr a3, .Lrtld_global_ro ldr a3, .Lrtld_global_ro
0: add a2, pc, a2 0: add a4, pc, a4
ldr a2, [a2, a3] ldr a4, [a4, a3]
ldr a2, [a2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET] ldr a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
# else # else
ldr a2, .Lhwcap ldr a4, .Lhwcap
ldr a2, [a2, #0] ldr a4, [a4, #0]
# endif # endif
# endif # endif
#endif #endif
#ifdef __SOFTFP__ #ifdef __SOFTFP__
tst a2, #HWCAP_ARM_VFP tst a4, #HWCAP_ARM_VFP
beq .Lno_vfp beq .Lno_vfp
#endif #endif
@ -98,7 +103,7 @@ ENTRY (__longjmp)
.Lno_vfp: .Lno_vfp:
#ifndef ARM_ASSUME_NO_IWMMXT #ifndef ARM_ASSUME_NO_IWMMXT
tst a2, #HWCAP_ARM_IWMMXT tst a4, #HWCAP_ARM_IWMMXT
beq .Lno_iwmmxt beq .Lno_iwmmxt
/* Restore the call-preserved iWMMXt registers. */ /* Restore the call-preserved iWMMXt registers. */
@ -118,6 +123,14 @@ ENTRY (__longjmp)
.Lno_iwmmxt: .Lno_iwmmxt:
#endif #endif
/* longjmp_target probe expects longjmp first argument (4@r0), second
argument (-4@r1), and target address (4@r14), respectively. */
LIBC_PROBE (longjmp_target, 3, 4@r0, -4@r1, 4@r14)
movs r0, r1 /* get the return value in place */
it eq
moveq r0, #1 /* can't let setjmp() return zero! */
DO_RET(lr) DO_RET(lr)
#ifdef NEED_HWCAP #ifdef NEED_HWCAP

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@ -28,9 +28,8 @@
/* The exact set of registers saved may depend on the particular core /* The exact set of registers saved may depend on the particular core
in use, as some coprocessor registers may need to be saved. The C in use, as some coprocessor registers may need to be saved. The C
Library ABI requires that the buffer be 8-byte aligned, and Library ABI requires that the buffer be 8-byte aligned, and
recommends that the buffer contain 64 words. The first 27 words recommends that the buffer contain 64 words. The first 26 words
are occupied by v1-v6, sl, fp, sp, pc, and d8-d15. (Note that are occupied by sp, lr, v1-v6, sl, fp, and d8-d15. */
d8-15 require 17 words, due to the use of fstmx.) */
typedef int __jmp_buf[64] __attribute__((__aligned__ (8))); typedef int __jmp_buf[64] __attribute__((__aligned__ (8)));
#endif #endif

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@ -30,7 +30,7 @@
# define JMP_BUF_REGLIST {v1-v6, sl, fp} # define JMP_BUF_REGLIST {v1-v6, sl, fp}
/* Index of __jmp_buf where the sp register resides. */ /* Index of __jmp_buf where the sp register resides. */
# define __JMP_BUF_SP 8 # define __JMP_BUF_SP 0
#endif #endif
#endif /* include/bits/setjmp.h */ #endif /* include/bits/setjmp.h */

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@ -17,6 +17,7 @@
<http://www.gnu.org/licenses/>. */ <http://www.gnu.org/licenses/>. */
#include <sysdep.h> #include <sysdep.h>
#include <stap-probe.h>
#include <bits/setjmp.h> #include <bits/setjmp.h>
#include <rtld-global-offsets.h> #include <rtld-global-offsets.h>
#include <arm-features.h> #include <arm-features.h>
@ -27,9 +28,11 @@ ENTRY (__sigsetjmp)
#endif #endif
mov ip, r0 mov ip, r0
/* Save registers */ /* setjmp probe expects sigsetjmp first argument (4@r0), second
sfi_breg ip, \ argument (-4@r1), and target address (4@r14), respectively. */
stmia \B!, JMP_BUF_REGLIST LIBC_PROBE (setjmp, 3, 4@r0, -4@r1, 4@r14)
/* Save sp and lr */
#ifdef PTR_MANGLE #ifdef PTR_MANGLE
mov a4, sp mov a4, sp
PTR_MANGLE2 (a4, a4, a3) PTR_MANGLE2 (a4, a4, a3)
@ -40,6 +43,9 @@ ENTRY (__sigsetjmp)
str sp, [ip], #4 str sp, [ip], #4
str lr, [ip], #4 str lr, [ip], #4
#endif #endif
/* Save registers */
sfi_breg ip, \
stmia \B!, JMP_BUF_REGLIST
#if !defined ARM_ASSUME_NO_IWMMXT || defined __SOFTFP__ #if !defined ARM_ASSUME_NO_IWMMXT || defined __SOFTFP__
# define NEED_HWCAP 1 # define NEED_HWCAP 1