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[S390] fix system call parameter functions.

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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>
This commit is contained in:
Martin Schwidefsky
2008-11-27 11:05:55 +01:00
parent ed313489ba
commit 59da21398e
8 changed files with 44 additions and 42 deletions
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6
arch/s390/kernel/signal.c
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@@ -160,7 +160,7 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
current->thread.fp_regs.fpc &= FPC_VALID_MASK;
restore_fp_regs(&current->thread.fp_regs);
regs->trap = -1; /* disable syscall checks */
regs->svcnr = 0; /* disable syscall checks */
return 0;
}
@@ -445,7 +445,7 @@ void do_signal(struct pt_regs *regs)
oldset = &current->blocked;
/* Are we from a system call? */
if (regs->trap == __LC_SVC_OLD_PSW) {
if (regs->svcnr) {
continue_addr = regs->psw.addr;
restart_addr = continue_addr - regs->ilc;
retval = regs->gprs[2];
@@ -462,7 +462,7 @@ void do_signal(struct pt_regs *regs)
case -ERESTART_RESTARTBLOCK:
regs->gprs[2] = -EINTR;
}
regs->trap = -1; /* Don't deal with this again. */
regs->svcnr = 0; /* Don't deal with this again. */
}
/* Get signal to deliver. When running under ptrace, at this point