x32 shares most system calls with x86-64, but unfortunately some
subsystem (the input subsystem is the chief offender) which require
is_compat() when operating with a 32-bit userspace.  The input system
actually has text files in sysfs whose meaning is dependent on
sizeof(long) in userspace!

We could solve this by having two completely disjoint system call
tables; requiring that each system call be duplicated.  This patch
takes a different approach: we add a flag to the system call number;
this flag doesn't affect the system call dispatch but requests compat
treatment from affected subsystems for the duration of the system call.

The change of cmpq to cmpl is safe since it immediately follows the
and.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This reverts commit d5e553d6, which
caused large numbers of build warnings on PowerPC.

This moves the #include <asm/asm-offsets.h> to <asm/syscall.h>, which
makes some kind of sense since NR_syscalls is syscalls related.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/20111214181545.6e13bc954cb7ddce9086e861@canb.auug.org.au

Most implementations of arch_syscall_addr() are the same, so create a
default version in common code and move the one piece that differs (the
syscall table) to asm/syscall.h.  New arch ports don't have to waste
time copying & pasting this simple function.

The s390/sparc versions need to be different, so document why.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1264498803-17278-1-git-send-email-vapier@gentoo.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Make syscall_get_nr() return int, so we always sign-extend
the low 32 bits of orig_ax in checks.
Signed-off-by: NRoland McGrath <roland@redhat.com>

Canonicalize a few remaining header guards, with the exception for
those which are still in subarchitecture directories.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Petr Tesarik noticed that I'd bungled the syscall_get_arguments code for
64-bit kernels, so it inverted the order of the syscall argument registers.
Petr wrote a patch to fix that, and I've amended it to fix the same braino
in the syscall_set_arguments code.
Original-by: NPetr Tesarik <ptesarik@suse.cz>
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The x86-tracehook code now contains this line in syscall_get_error():

	return error >= -4095L ? error : 0;

Hard-wiring a constant is not nice. Let's use the IS_ERR_VALUE macro
from linux/err.h instead.
Signed-off-by: NPetr Tesarik <ptesarik@suse.cz>
Cc: utrace-devel@redhat.com
Acked-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add asm/syscall.h for x86 with all the required entry points.
This will allow arch-independent tracing code for system calls.
Signed-off-by: NRoland McGrath <roland@redhat.com>