diff options
| author | Bodo Stroesser <bstroesser@fujitsu-siemens.com> | 2005-06-04 15:43:32 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-06-04 17:13:00 -0700 |
| commit | c5c3a6d8fe923b8780b9cd10e72344b8cf8518b5 (patch) | |
| tree | 7b6b663ae1668befa18f8ff0b95f0cc2e254471d /arch/s390 | |
| parent | 778959db97c7ed8eed4025916916b17a4629ce3d (diff) | |
[PATCH] s390: uml ptrace fixes
To make UML build and run on s390, I needed to do these two little
changes:
1) UML includes some of the subarch's (s390) headers. I had to
change one of them with the following one-liner, to make this
compile. AFAICS, this change doesn't break compilation of s390
itself.
2) UML needs to intercept syscalls via ptrace to invalidate the syscall,
read syscall's parameters and write the result with the result of
UML's syscall processing. Also, UML needs to make sure, that the host
does no syscall restart processing. On i386 for example, this can be
done by writing -1 to orig_eax on the 2nd syscall interception
(orig_eax is the syscall number, which after the interception is used
as a "interrupt was a syscall" flag only.
Unfortunately, s390 holds syscall number and syscall result in gpr2 and
its "interrupt was a syscall" flag (trap) is unreachable via ptrace.
So I changed the host to set trap to -1, if the syscall number is changed
to an invalid value on the first syscall interception.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kernel/ptrace.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index 329d9391c83..06afa3103ac 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -761,6 +761,13 @@ syscall_trace(struct pt_regs *regs, int entryexit) ? 0x80 : 0)); /* + * If the debuffer has set an invalid system call number, + * we prepare to skip the system call restart handling. + */ + if (!entryexit && regs->gprs[2] >= NR_syscalls) + regs->trap = -1; + + /* * this isn't the same as continuing with a signal, but it will do * for normal use. strace only continues with a signal if the * stopping signal is not SIGTRAP. -brl |