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.

diff --git a/ChangeLog b/ChangeLog
index 5789022a6c08159e105d96ccad897e24506b0a3a..caa89170d73a62ac4f13d19d0ef47dcae70deb87 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -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>
 
        * sysdeps/s390/fpu/libm-test-ulps: Regenerate.

diff --git a/sysdeps/arm/__longjmp.S b/sysdeps/arm/__longjmp.S
index 27c57a12df49686e9481de4852a98c5d6c5d00a7..08521e5374ac78f58fcaa3898504dba5e141e9cd 100644 (file)
--- a/sysdeps/arm/__longjmp.S
+++ b/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>
@@ -25,31 +26,35 @@
 
 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)
-       mov     sp, a4
-       ldr     a4, [ip], #4
-       PTR_DEMANGLE2 (lr, a4, a3)
+       PTR_DEMANGLE (a4, a4, a3, r4)
+       cfi_undefined (r4)
+       ldr     r4, [ip], #4
+       PTR_DEMANGLE2 (r4, r4, a3)
 #else
-       ldr     sp, [ip], #4
-       ldr     lr, [ip], #4
+       ldr     a4, [ip], #4
+       ldr     r4, [ip], #4
+       cfi_undefined (r4)
 #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 (v2)
        cfi_restore (v3)
@@ -67,27 +72,27 @@ ENTRY (__longjmp)
 
 #ifdef NEED_HWCAP
 # ifdef IS_IN_rtld
-       ldr     a2, 1f
+       ldr     a4, 1f
        ldr     a3, .Lrtld_local_ro
-0:     add     a2, pc, a2
-       add     a2, a2, a3
-       ldr     a2, [a2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
+0:     add     a4, pc, a4
+       add     a4, a4, a3
+       ldr     a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
 # else
 #  ifdef PIC
-       ldr     a2, 1f
+       ldr     a4, 1f
        ldr     a3, .Lrtld_global_ro
-0:     add     a2, pc, a2
-       ldr     a2, [a2, a3]
-       ldr     a2, [a2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
+0:     add     a4, pc, a4
+       ldr     a4, [a4, a3]
+       ldr     a4, [a4, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
 #  else
-       ldr     a2, .Lhwcap
-       ldr     a2, [a2, #0]
+       ldr     a4, .Lhwcap
+       ldr     a4, [a4, #0]
 #  endif
 # endif
 #endif
 
 #ifdef __SOFTFP__
-       tst     a2, #HWCAP_ARM_VFP
+       tst     a4, #HWCAP_ARM_VFP
        beq     .Lno_vfp
 #endif
 
@@ -98,7 +103,7 @@ ENTRY (__longjmp)
 .Lno_vfp:
 
 #ifndef ARM_ASSUME_NO_IWMMXT
-       tst     a2, #HWCAP_ARM_IWMMXT
+       tst     a4, #HWCAP_ARM_IWMMXT
        beq     .Lno_iwmmxt
 
        /* Restore the call-preserved iWMMXt registers.  */
@@ -118,6 +123,14 @@ ENTRY (__longjmp)
 .Lno_iwmmxt:
 #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)
 
 #ifdef NEED_HWCAP

diff --git a/sysdeps/arm/bits/setjmp.h b/sysdeps/arm/bits/setjmp.h
index 41423b2c3bc657cc3c4e0dffdea83353e486c555..a68735993a0dc744dcb3a715fb2f9769f2aef3ab 100644 (file)
--- a/sysdeps/arm/bits/setjmp.h
+++ b/sysdeps/arm/bits/setjmp.h
@@ -28,9 +28,8 @@
 /* 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
    Library ABI requires that the buffer be 8-byte aligned, and
-   recommends that the buffer contain 64 words.  The first 27 words
-   are occupied by v1-v6, sl, fp, sp, pc, and d8-d15.  (Note that
-   d8-15 require 17 words, due to the use of fstmx.)  */
+   recommends that the buffer contain 64 words.  The first 26 words
+   are occupied by sp, lr, v1-v6, sl, fp, and d8-d15.  */
 typedef int __jmp_buf[64] __attribute__((__aligned__ (8)));
 #endif
 

diff --git a/sysdeps/arm/include/bits/setjmp.h b/sysdeps/arm/include/bits/setjmp.h
index 220dfe8d9668c967596f89c791d42290df9de0ac..5877c1f6597faf0333028d0d518dc3818157646f 100644 (file)
--- a/sysdeps/arm/include/bits/setjmp.h
+++ b/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/sysdeps/arm/setjmp.S b/sysdeps/arm/setjmp.S
index b0b45ed8da1e6f5215209fa4b2f971d947a0956e..5e55ca50616910f70a56a6d5c2d83691b7bafc56 100644 (file)
--- a/sysdeps/arm/setjmp.S
+++ b/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