From: Hans-Christian Egtvedt <egtvedt@samfundet.no>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
Haavard Skinnemoen <hskinnemoen@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
David Howells <dhowells@redhat.com>,
Dave Jones <davej@redhat.com>, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arch: avr32: add dummy syscalls
Date: Sun, 27 Jan 2013 21:39:54 +0100 [thread overview]
Message-ID: <20130127203954.GA22063@samfundet.no> (raw)
In-Reply-To: <20130127203009.GG4503@ZenIV.linux.org.uk>
Around Sun 27 Jan 2013 20:30:09 +0000 or thereabout, Al Viro wrote:
> On Sun, Jan 27, 2013 at 08:57:14PM +0100, Hans-Christian Egtvedt wrote:
>> Around Sun 27 Jan 2013 13:50:15 +0100 or thereabout, Matthias Brugger wrote:
>> > This patch adds dummy syscalls so that compiling
>> > for this architecture does not provoke warnings when
>> > checksyscalls.sh is called.
>>
>> Does any of these syscalls take more than 5 arguments? If so, it is also
>> needed to do some stack handling. I would rather not add syscalls that cause
>> the kernel to misbehave.
>
> BTW, it might make sense to teach SYSCALL_DEFINE6 to generate such a wrapper
> on avr32. How about something along the lines of
> * SYSCALL_DEFINE6(foo, ...) generating (via asm volatile, right next to
> sys_foo())
> __sys_##foo:
> pushm lr
> st.w --sp, r3
> call sys_##foo
> sub sp, -4
> popm pc
> * SYSCALL_DEFINE[0..5](foo, ...) generating
> SYSCALL_ALIAS(__sys_foo, sys_foo)
> * syscall_table.S beginning with
> .section .rodata,"a",@progbits
> .type sys_call_table,@object
> .global sys_call_table
> .align 2
> #define SYS(name) __sys_##name
> sys_call_table:
> SYS(restart_syscall)
> SYS(exit)
> SYS(fork)
> ...
>
> If you are OK with going that way, I could probably put together patches doing
> just that. Note that for rt_sigsuspend/rt_sigreturn/sigaltstack the wrappers
> are not needed at all - they can just use current_pt_regs() in syscall body.
> IOW, all of syscall-stubs.S could be killed.
Nice, could you put together the preprocessor stuff in a patch? It would be
great to not having to write a re-occuring stub for each syscall that has 6+
arguments.
Thanks for looking at this.
--
mvh
Hans-Christian Egtvedt
next prev parent reply other threads:[~2013-01-27 20:40 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-27 12:50 [PATCH] arch: avr32: add dummy syscalls Matthias Brugger
2013-01-27 19:57 ` Hans-Christian Egtvedt
2013-01-27 20:30 ` Al Viro
2013-01-27 20:39 ` Hans-Christian Egtvedt [this message]
2013-02-04 0:10 ` Al Viro
2013-02-04 0:30 ` Al Viro
2013-02-04 1:31 ` Al Viro
2013-02-04 3:02 ` Al Viro
2013-02-04 4:52 ` Håvard Skinnemoen
2013-02-04 5:05 ` Al Viro
2013-02-04 5:35 ` Håvard Skinnemoen
2013-02-04 15:39 ` Al Viro
2013-02-04 16:34 ` Håvard Skinnemoen
2013-02-04 22:53 ` Al Viro
2013-02-05 8:06 ` Hans-Christian Egtvedt
2013-02-04 3:21 ` H. Peter Anvin
2013-01-28 2:45 ` Håvard Skinnemoen
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