On 11/12/2014 08:00 PM, Will Deacon wrote:
On Wed, Nov 12, 2014 at 10:46:01AM +0000, AKASHI Takahiro wrote:
On 11/07/2014 11:04 PM, Oleg Nesterov wrote:
To me the fact that PTRACE_SET_SYSCALL can be undefined and syscall_set_nr() is very much arch-dependant (but most probably trivial) means that this code should live in arch_ptrace().
Thinking of Oleg's comment above, it doesn't make sense neither to define generic NT_SYSTEM_CALL (user_regset) in uapi/linux/elf.h and implement it in ptrace_regset() in kernel/ptrace.c with arch-defined syscall_(g)set_nr().
Since we should have the same interface on arm and arm64, we'd better implement ptrace(PTRACE_SET_SYSCALL) locally on arm64 for now (as I originally submitted).
I think the regset approach is cleaner. We already do something similar for TLS. That would be implemented under arch/arm64/ with it's own NT type.
Okey, so arm64 goes its own way :) Or do you want to have a similar regset on arm, too? (In this case, NT_ARM_SYSTEM_CALL can be shared in uapi/linux/elf.h)
-Takahiro AKASHI
Will