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Date: Thu, 30 Oct 2014 07:30:28 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>, Rabin Vincent <rabin@rab.in>,
        linux-arm-kernel@lists.infradead.org, Ingo Molnar <mingo@redhat.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tracing/syscalls: ignore numbers outside NR_syscalls'
 range
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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.

-- Steve