Messages in this thread | | | Date | Fri, 7 Nov 2014 12:11:19 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [RFC] ptrace: add generic SET_SYSCALL request |
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On Fri, Nov 07, 2014 at 01:03:00PM +0100, Arnd Bergmann wrote: > On Friday 07 November 2014 11:55:51 Will Deacon wrote: > > We need this for arm64 and, since all architectures seem to have a mechanism > > for setting a system call via ptrace, moving it to generic code should make > > sense for new architectures too, no? > > It makes a little more sense now, but I still don't understand why you > need to set the system call number via ptrace. What is this used for, > and why doesn't any other architecture have this?
All other architectures have a way. x86, for example, you set orig_eax (or orig_rax) to change the syscall number. On ARM, that doesn't work because we don't always pass the syscall number in a register.
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