Messages in this thread | | | Date | Thu, 9 Oct 2014 10:23:58 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v7 1/6] arm64: ptrace: add PTRACE_SET_SYSCALL |
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On Wed, Oct 08, 2014 at 04:30:18PM +0100, Kees Cook wrote: > On Wed, Oct 8, 2014 at 9:13 AM, Will Deacon <will.deacon@arm.com> wrote: > > On Thu, Oct 02, 2014 at 10:46:11AM +0100, AKASHI Takahiro wrote: > >> 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.
> 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
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