Hi Will, Kees

#Sorry for this late ping,

On 10/09/2014 06:23 PM, Will Deacon wrote:

On Wed, Oct 08, 2014 at 04:30:18PM +0100, Kees Cook wrote:

quoted

On Wed, Oct 8, 2014 at 9:13 AM, Will Deacon [off-list ref] wrote:

quoted

On Thu, Oct 02, 2014 at 10:46:11AM +0100, AKASHI Takahiro wrote:

quoted

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index fe63ac5..2842f9f 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c

@@ -1082,7 +1082,19 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
  long arch_ptrace(struct task_struct *child, long request,
                unsigned long addr, unsigned long data)
  {
-     return ptrace_request(child, request, addr, data);
+     int ret;
+
+     switch (request) {
+             case PTRACE_SET_SYSCALL:
+                     task_pt_regs(child)->syscallno = data;
+                     ret = 0;
+                     break;
+             default:
+                     ret = ptrace_request(child, request, addr, data);
+                     break;
+     }
+
+     return ret;
  }

I still don't understand why this needs to be in arch-specific code. Can't
we implement this in generic code and get architectures to implement
something like syscall_set_nr if they want the generic interface?

Personally, I'd rather see this land as-is in the arm64 tree, and then
later optimize PTRACE_SET_SYSCALL out of arm/ and arm64/, especially
since only these architectures implement this at the moment.

Why? It should be really straightforward to do this in core code from the
get-go and experience shows that, if we don't do it now, it will never
happen.

How should I deal with this issue? I would be able to go either way.

Other than that, I will submit v8 patch series with a few very minor updates:
- use compat_uint_t in struct compat_siginfo
- use a new call interface of secure_computing(void)
- modify and clarify comments in syscall_trace_enter()

Thanks,
-Takahiro AKASHI

quoted

This is my plan for the asm-generic seccomp.h too -- I'd rather avoid
touching other architectures in this series, as it's easier to review
this way. Then we can optimize the code in a separate series, which
will have those changes isolated, etc.

But this doesn't need to touch any other architectures...

Will