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S390: Fix backtrace in vdso functions.

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On s390, GDB fails to show the complete backtrace from within vdso functions.
The macro INTERNAL_VSYSCALL_CALL saves the return address in r14 to r10
before branching to the vdso function. The branch-instruction updates r14
in order to let the vdso function return. Then the original address in r14 is
restored from r10. Unfortunately, there are no cfi-rules and GDB fails.

Furthermore the call of the vdso function does not comply with the s390 ABI
as no stack-frame for the vdso-function is generated.

This patch removes the s390 specific macro INTERNAL_VSYSCALL_CALL
and the common implementation in sysdeps/unix/sysv/linux/sysdep-vdso.h is used.
Then the vdso function is called via function-pointer and GCC generates a
new stack-frame and emits all needed cfi-rules.

The defines CLOBBER_[0-6] are removed as they  were only used in macro
INTERNAL_VSYSCALL_CALL.

The macro INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK is not used on s390.
The only user is power. Thus it is removed from s390 sysdep.h.

ChangeLog:

	* sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
	(INTERNAL_VSYSCALL_CALL, CLOBBER_0, CLOBBER_1, CLOBBER_2,
	 CLOBBER_3, CLOBBER_4, CLOBBER_5, CLOBBER_6,
	INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK): Remove.
	* sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h: Likewise.
This commit is contained in:
Stefan Liebler 2017-12-04 16:40:13 +01:00
parent 7863a71181
commit 478593e637
3 changed files with 8 additions and 72 deletions
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8
ChangeLog
View File

@ -1,3 +1,11 @@
2017-12-04 Stefan Liebler <stli@linux.vnet.ibm.com>
* sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
(INTERNAL_VSYSCALL_CALL, CLOBBER_0, CLOBBER_1, CLOBBER_2,
CLOBBER_3, CLOBBER_4, CLOBBER_5, CLOBBER_6,
INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK): Remove.
* sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h: Likewise.
2017-12-04 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
[BZ #5997]

36
sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h
View File

@ -271,48 +271,12 @@
#define ASMFMT_5 , "0" (gpr2), "d" (gpr3), "d" (gpr4), "d" (gpr5), "d" (gpr6)
#define ASMFMT_6 , "0" (gpr2), "d" (gpr3), "d" (gpr4), "d" (gpr5), "d" (gpr6), "d" (gpr7)
#define CLOBBER_0 , "3", "4", "5"
#define CLOBBER_1 , "3", "4", "5"
#define CLOBBER_2 , "4", "5"
#define CLOBBER_3 , "5"
#define CLOBBER_4
#define CLOBBER_5
#define CLOBBER_6
/* List of system calls which are supported as vsyscalls. */
#define HAVE_CLOCK_GETRES_VSYSCALL 1
#define HAVE_CLOCK_GETTIME_VSYSCALL 1
#define HAVE_GETTIMEOFDAY_VSYSCALL 1
#define HAVE_GETCPU_VSYSCALL 1
/* This version is for internal uses when there is no desire
to set errno */
#define INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK(name, err, nr, args...) \
({ \
long int _ret = ENOSYS; \
\
__typeof (__vdso_##name) vdsop = __vdso_##name; \
PTR_DEMANGLE (vdsop); \
if (vdsop != NULL) \
_ret = INTERNAL_VSYSCALL_CALL (vdsop, err, nr, ##args); \
else \
err = 1 << 28; \
_ret; \
})
#define INTERNAL_VSYSCALL_CALL(fn, err, nr, args...) \
({ \
DECLARGS_##nr(args) \
register long _ret __asm__("2"); \
__asm__ __volatile__ ( \
"lr 10,14\n\t" \
"basr 14,%1\n\t" \
"lr 14,10\n\t" \
: "=d" (_ret) \
: "d" (fn) ASMFMT_##nr \
: "cc", "memory", "0", "1", "10" CLOBBER_##nr); \
_ret; })
/* Pointer mangling support. */
#if IS_IN (rtld)
/* We cannot use the thread descriptor because in ld.so we use setjmp

36
sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
View File

@ -277,14 +277,6 @@
#define ASMFMT_5 , "0" (gpr2), "d" (gpr3), "d" (gpr4), "d" (gpr5), "d" (gpr6)
#define ASMFMT_6 , "0" (gpr2), "d" (gpr3), "d" (gpr4), "d" (gpr5), "d" (gpr6), "d" (gpr7)
#define CLOBBER_0 , "3", "4", "5"
#define CLOBBER_1 , "3", "4", "5"
#define CLOBBER_2 , "4", "5"
#define CLOBBER_3 , "5"
#define CLOBBER_4
#define CLOBBER_5
#define CLOBBER_6
/* List of system calls which are supported as vsyscalls. */
#define HAVE_CLOCK_GETRES_VSYSCALL 1
#define HAVE_CLOCK_GETTIME_VSYSCALL 1
@ -293,34 +285,6 @@
#define SINGLE_THREAD_BY_GLOBAL 1
/* This version is for internal uses when there is no desire
to set errno */
#define INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK(name, err, nr, args...) \
({ \
long int _ret = ENOSYS; \
\
__typeof (__vdso_##name) vdsop = __vdso_##name; \
PTR_DEMANGLE (vdsop); \
if (vdsop != NULL) \
_ret = INTERNAL_VSYSCALL_CALL (vdsop, err, nr, ##args); \
else \
err = 1 << 28; \
_ret; \
})
#define INTERNAL_VSYSCALL_CALL(fn, err, nr, args...) \
({ \
DECLARGS_##nr(args) \
register long _ret __asm__("2"); \
__asm__ __volatile__ ( \
"lgr 10,14\n\t" \
"basr 14,%1\n\t" \
"lgr 14,10\n\t" \
: "=d" (_ret) \
: "a" (fn) ASMFMT_##nr \
: "cc", "memory", "0", "1", "10" CLOBBER_##nr); \
_ret; })
/* Pointer mangling support. */
#if IS_IN (rtld)
/* We cannot use the thread descriptor because in ld.so we use setjmp