[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <4F210D9B.3030808@redhat.com>
Date: Thu, 26 Jan 2012 08:23:55 +0000
From: Pedro Alves <palves@...hat.com>
To: Jamie Lokier <jamie@...reable.org>
CC: Denys Vlasenko <vda.linux@...glemail.com>,
Oleg Nesterov <oleg@...hat.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Indan Zupancic <indan@....nu>,
Andi Kleen <andi@...stfloor.org>,
Andrew Lutomirski <luto@....edu>,
Will Drewry <wad@...omium.org>, linux-kernel@...r.kernel.org,
keescook@...omium.org, john.johansen@...onical.com,
serge.hallyn@...onical.com, coreyb@...ux.vnet.ibm.com,
pmoore@...hat.com, eparis@...hat.com, djm@...drot.org,
segoon@...nwall.com, rostedt@...dmis.org, jmorris@...ei.org,
scarybeasts@...il.com, avi@...hat.com, penberg@...helsinki.fi,
viro@...iv.linux.org.uk, mingo@...e.hu, akpm@...ux-foundation.org,
khilman@...com, borislav.petkov@....com, amwang@...hat.com,
ak@...ux.intel.com, eric.dumazet@...il.com, gregkh@...e.de,
dhowells@...hat.com, daniel.lezcano@...e.fr,
linux-fsdevel@...r.kernel.org,
linux-security-module@...r.kernel.org, olofj@...omium.org,
mhalcrow@...gle.com, dlaor@...hat.com,
Roland McGrath <mcgrathr@...omium.org>
Subject: Re: Compat 32-bit syscall entry from 64-bit task!?
On 01/26/2012 12:59 AM, Jamie Lokier wrote:
> Tracers mainly want to know if it's a 32-bit or 64-bit syscall, not
> whether it's compat as such.
Another idea, avoiding new PTRACE_EVENTs per arch, would be to make
the abi32/abi64/compat/whatnot discriminator retrievable with PTRACE_GETEVENTMSG
instead. So you'd get PTRACE_EVENT_SYSCALL_ENTRY|EXIT, or the regular old
0x80|SIGTRAP, you'd still fetch the syscall number from $orig_ax (or whatever means
for other archs), as usual, then have extra syscall info in PTRACE_GETEVENTMSG.
I don't know if it'd be simple to make it possible to do PTRACE_GETEVENTMSG
on a 0x80|SIGTRAP trap, but I imagine it so.
-> wait
<- 0x80|SIGTRAP (or PTRACE_EVENT_SYSCALL_ENTRY)
-> read regs, find out syscall number
-> PTRACE_GETEVENTMSG, figure out which entry mode was used.
--
Pedro Alves
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists