aboutsummaryrefslogtreecommitdiff
path: root/sysdeps
diff options
context:
space:
mode:
authorAdhemerval Zanella <azanella@linux.vnet.ibm.com>2013-08-20 15:01:59 -0500
committerAdhemerval Zanella <azanella@linux.vnet.ibm.com>2013-08-20 15:05:49 -0500
commitd400dcac5e66047f86291d1a4b90fffb6327dc43 (patch)
treed2ff562dde1ad639f96e9fbe163e07b94d782854 /sysdeps
parentc980f2f4fe0f5d301f706017a1f7e4e942193ec0 (diff)
downloadglibc-d400dcac5e66047f86291d1a4b90fffb6327dc43.tar
glibc-d400dcac5e66047f86291d1a4b90fffb6327dc43.tar.gz
glibc-d400dcac5e66047f86291d1a4b90fffb6327dc43.tar.bz2
glibc-d400dcac5e66047f86291d1a4b90fffb6327dc43.zip
PowerPC: fix backtrace to handle signal trampolines
This patch fixes backtrace for PPC32 and PPC64 to correctly handle signal trampolines. The 'debug/tst-backtrace6.c' also check for SA_SIGINFO handling, where is triggers another vDSO symbols for PPC32.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/powerpc/powerpc32/backtrace.c66
-rw-r--r--sysdeps/powerpc/powerpc64/backtrace.c36
-rw-r--r--sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h7
-rw-r--r--sysdeps/unix/sysv/linux/powerpc/init-first.c16
4 files changed, 123 insertions, 2 deletions
diff --git a/sysdeps/powerpc/powerpc32/backtrace.c b/sysdeps/powerpc/powerpc32/backtrace.c
index b4b11dd03c..8d413e620f 100644
--- a/sysdeps/powerpc/powerpc32/backtrace.c
+++ b/sysdeps/powerpc/powerpc32/backtrace.c
@@ -18,6 +18,9 @@
#include <execinfo.h>
#include <stddef.h>
+#include <string.h>
+#include <signal.h>
+#include <bits/libc-vdso.h>
/* This is the stack layout we see with every stack frame.
Note that every routine is required by the ABI to lay out the stack
@@ -35,6 +38,46 @@ struct layout
void *return_address;
};
+#define SIGNAL_FRAMESIZE 64
+
+/* Since the signal handler is just like any other function it needs to
+ save/restore its LR and it will save it into callers stack frame.
+ Since a signal handler doesn't have a caller, the kernel creates a
+ dummy frame to make it look like it has a caller. */
+struct signal_frame_32 {
+ char dummy[SIGNAL_FRAMESIZE];
+ struct sigcontext sctx;
+ mcontext_t mctx;
+ /* We don't care about the rest, since IP value is at 'mctx' field. */
+};
+
+static inline int
+is_sigtramp_address (unsigned int nip)
+{
+#ifdef SHARED
+ if (nip == (unsigned int)__vdso_sigtramp32)
+ return 1;
+#endif
+ return 0;
+}
+
+struct rt_signal_frame_32 {
+ char dummy[SIGNAL_FRAMESIZE + 16];
+ siginfo_t info;
+ struct ucontext uc;
+ /* We don't care about the rest, since IP value is at 'uc' field. */
+};
+
+static inline int
+is_sigtramp_address_rt (unsigned int nip)
+{
+#ifdef SHARED
+ if (nip == (unsigned int)__vdso_sigtramp_rt32)
+ return 1;
+#endif
+ return 0;
+}
+
int
__backtrace (void **array, int size)
{
@@ -50,7 +93,28 @@ __backtrace (void **array, int size)
for ( count = 0;
current != NULL && count < size;
current = current->next, count++)
- array[count] = current->return_address;
+ {
+ gregset_t *gregset = NULL;
+
+ array[count] = current->return_address;
+
+ /* Check if the symbol is the signal trampoline and get the interrupted
+ * symbol address from the trampoline saved area. */
+ if (is_sigtramp_address ((unsigned int)current->return_address))
+ {
+ struct signal_frame_32 *sigframe =
+ (struct signal_frame_32*) current;
+ gregset = &sigframe->mctx.gregs;
+ }
+ else if (is_sigtramp_address_rt ((unsigned int)current->return_address))
+ {
+ struct rt_signal_frame_32 *sigframe =
+ (struct rt_signal_frame_32*) current;
+ gregset = &sigframe->uc.uc_mcontext.uc_regs->gregs;
+ }
+ if (gregset)
+ array[++count] = (void*)((*gregset)[PT_NIP]);
+ }
/* It's possible the second-last stack frame can't return
(that is, it's __libc_start_main), in which case
diff --git a/sysdeps/powerpc/powerpc64/backtrace.c b/sysdeps/powerpc/powerpc64/backtrace.c
index 2d3e051cb9..9b9a9f19da 100644
--- a/sysdeps/powerpc/powerpc64/backtrace.c
+++ b/sysdeps/powerpc/powerpc64/backtrace.c
@@ -18,6 +18,9 @@
#include <execinfo.h>
#include <stddef.h>
+#include <string.h>
+#include <signal.h>
+#include <bits/libc-vdso.h>
/* This is the stack layout we see with every stack frame.
Note that every routine is required by the ABI to lay out the stack
@@ -38,6 +41,27 @@ struct layout
void *return_address;
};
+/* Since the signal handler is just like any other function it needs to
+ save/restore its LR and it will save it into callers stack frame.
+ Since a signal handler doesn't have a caller, the kernel creates a
+ dummy frame to make it look like it has a caller. */
+struct signal_frame_64 {
+#define SIGNAL_FRAMESIZE 128
+ char dummy[SIGNAL_FRAMESIZE];
+ struct ucontext uc;
+ /* We don't care about the rest, since the IP value is at 'uc' field. */
+};
+
+static inline int
+is_sigtramp_address (unsigned long nip)
+{
+#ifdef SHARED
+ if (nip == (unsigned long)__vdso_sigtramp_rt64)
+ return 1;
+#endif
+ return 0;
+}
+
int
__backtrace (void **array, int size)
{
@@ -53,7 +77,17 @@ __backtrace (void **array, int size)
for ( count = 0;
current != NULL && count < size;
current = current->next, count++)
- array[count] = current->return_address;
+ {
+ array[count] = current->return_address;
+
+ /* Check if the symbol is the signal trampoline and get the interrupted
+ * symbol address from the trampoline saved area. */
+ if (is_sigtramp_address ((unsigned long)current->return_address))
+ {
+ struct signal_frame_64 *sigframe = (struct signal_frame_64*) current;
+ array[++count] = (void*)sigframe->uc.uc_mcontext.gp_regs[PT_NIP];
+ }
+ }
/* It's possible the second-last stack frame can't return
(that is, it's __libc_start_main), in which case
diff --git a/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h b/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h
index 8b195db1bf..ba54de4eb0 100644
--- a/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h
+++ b/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h
@@ -34,6 +34,13 @@ extern void *__vdso_getcpu;
extern void *__vdso_time;
+#if defined(__PPC64__) || defined(__powerpc64__)
+extern void *__vdso_sigtramp_rt64;
+#else
+extern void *__vdso_sigtramp32;
+extern void *__vdso_sigtramp_rt32;
+#endif
+
/* This macro is needed for PPC64 to return a skeleton OPD entry of a vDSO
symbol. This works because _dl_vdso_vsym always return the function
address, and no vDSO symbols use the TOC or chain pointers from the OPD
diff --git a/sysdeps/unix/sysv/linux/powerpc/init-first.c b/sysdeps/unix/sysv/linux/powerpc/init-first.c
index f6f05f0ba2..061715f875 100644
--- a/sysdeps/unix/sysv/linux/powerpc/init-first.c
+++ b/sysdeps/unix/sysv/linux/powerpc/init-first.c
@@ -29,6 +29,12 @@ void *__vdso_clock_getres;
void *__vdso_get_tbfreq;
void *__vdso_getcpu;
void *__vdso_time;
+#if defined(__PPC64__) || defined(__powerpc64__)
+void *__vdso_sigtramp_rt64;
+#else
+void *__vdso_sigtramp32;
+void *__vdso_sigtramp_rt32;
+#endif
static inline void
_libc_vdso_platform_setup (void)
@@ -46,6 +52,16 @@ _libc_vdso_platform_setup (void)
__vdso_getcpu = _dl_vdso_vsym ("__kernel_getcpu", &linux2615);
__vdso_time = _dl_vdso_vsym ("__kernel_time", &linux2615);
+
+ /* PPC64 uses only one signal trampoline symbol, while PPC32 will use
+ two depending if SA_SIGINFO is used (__kernel_sigtramp_rt32) or not
+ (__kernel_sigtramp32). */
+#if defined(__PPC64__) || defined(__powerpc64__)
+ __vdso_sigtramp_rt64 = _dl_vdso_vsym ("__kernel_sigtramp_rt64", &linux2615);
+#else
+ __vdso_sigtramp32 = _dl_vdso_vsym ("__kernel_sigtramp32", &linux2615);
+ __vdso_sigtramp_rt32 = _dl_vdso_vsym ("__kernel_sigtramp_rt32", &linux2615);
+#endif
}
# define VDSO_SETUP _libc_vdso_platform_setup