Messages in this thread | | | Date | Thu, 30 Oct 2014 11:35:23 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH] tracing/syscalls: ignore numbers outside NR_syscalls' range |
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On Thu, Oct 30, 2014 at 07:30:28AM -0400, Steven Rostedt wrote: > On Thu, 30 Oct 2014 11:14:41 +0000 > Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > > > > We have always had syscall number range of 0x900000 or so. The tracing > > design does not expect that. Therefore, the tracing design did not take > > account of ARM when it was created. Therefore, it's up to the tracing > > people to decide how to properly fit their ill-designed subsystem into > > one of the popular and well-established kernel architectures - or at > > least suggest a way to work around this issue. > > > > > Fine, lets define a MAX_SYSCALL_NR that is by default NR_syscalls, but > an architecture can override it. > > In trace_syscalls.c, where the checks are done, have this: > > #ifndef MAX_SYSCALL_NR > # define MAX_SYSCALL_NR NR_syscalls > #endif > > change all the checks to test against MAX_SYSCALL_NR instead of > NR_syscalls. > > Then in arch/arm/include/asm/syscall.h have: > > #define MAX_SYSCALL_NR 0xa00000 > > or whatever would be the highest syscall number for ARM.
Or do we just ignore the high "special" ARM syscalls and treat them (from the tracing point of view) as non-syscalls, avoiding the allocation of something around 1.2MB for the syscall bitmap. I really don't know, I don't use any of this tracing stuff, so it isn't something I care about.
Maybe those who do use the facility should have an input here?
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