[S390] fix system call parameter functions.

syscall_get_nr() currently returns a valid result only if the call
chain of the traced process includes do_syscall_trace_enter(). But
collect_syscall() can be called for any sleeping task, the result of
syscall_get_nr() in general is completely bogus.

To make syscall_get_nr() work for any sleeping task the traps field
in pt_regs is replace with svcnr - the system call number the process
is executing. If svcnr == 0 the process is not on a system call path.

The syscall_get_arguments and syscall_set_arguments use regs->gprs[2]
for the first system call parameter. This is incorrect since gprs[2]
may have been overwritten with the system call number if the call
chain includes do_syscall_trace_enter. Use regs->orig_gprs2 instead.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index fa28ecae636b..3d144e6020c6 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -32,7 +32,7 @@ int main(void)
         DEFINE(__PT_GPRS, offsetof(struct pt_regs, gprs));
         DEFINE(__PT_ORIG_GPR2, offsetof(struct pt_regs, orig_gpr2));
         DEFINE(__PT_ILC, offsetof(struct pt_regs, ilc));
-        DEFINE(__PT_TRAP, offsetof(struct pt_regs, trap));
+        DEFINE(__PT_SVCNR, offsetof(struct pt_regs, svcnr));
         DEFINE(__PT_SIZE, sizeof(struct pt_regs));
         BLANK();
         DEFINE(__SF_BACKCHAIN, offsetof(struct stack_frame, back_chain));