Impact: cleanup

With the recent changes in the 32-bit code to make system calls which
use struct pt_regs take a pointer, sys_rt_sigreturn() have become
identical between 32 and 64 bits, and both are empty wrappers around
do_rt_sigreturn().  Remove both wrappers and rename both to
sys_rt_sigreturn().

Cc: Brian Gerst <brgerst@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Some syscalls need to access the pt_regs structure, either to copy
user register state or to modifiy it.  This patch adds stubs to load
the address of the pt_regs struct into the %eax register, and changes
the syscalls to take the pointer as an argument instead of relying on
the assumption that the pt_regs structure overlaps the function
arguments.

Drop the use of regparm(1) due to concern about gcc bugs, and to move
in the direction of the eventual removal of regparm(0) for asmlinkage.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Some syscalls need to access the pt_regs structure, either to copy
user register state or to modifiy it.  This patch adds stubs to load
the address of the pt_regs struct into the %eax register, and changes
the syscalls to regparm(1) to receive the pt_regs pointer as the
first argument.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

fix the following 'make headers_check' warning:

  usr/include/asm/prctl.h:10: extern's make no sense in userspace
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>

This reverts commit 4217458d.

Justin Madru bisected this commit, it was causing weird Firefox
crashes.

The reason is that GCC mis-optimizes (re-uses) the on-stack parameters of
the calling frame, which corrupts the syscall return pt_regs state and
thus corrupts user-space register state.

So we go back to the slightly less clean but more optimization-safe
method of getting to pt_regs. Also add a comment to explain this.

Resolves: http://bugzilla.kernel.org/show_bug.cgi?id=12505Reported-and-bisected-by: NJustin Madru <jdm64@gawab.com>
Tested-by: NJustin Madru <jdm64@gawab.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

In asm/syscalls.h move out sys_set_thread_area() and sys_get_thread_area()
as they are common for both 32 and 64 bit.
Signed-off-by: NJaswinder Singh <jaswinder@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

In asm/syscalls.h moved out sys_modify_ldt from CONFIG_X86_32 as it is
common for both 32 and 64 bit.
Signed-off-by: NJaswinder Singh <jaswinder@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup on 32-bit

Peter pointed this parameter can be changed.
Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

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

Signed-off-by: NJaswinder Singh <jaswinder@infradead.org>

declared following syscalls in asm-x86/syscalls.h:
sys_vm86old, sys_vm86
Signed-off-by: NJaswinder Singh <jaswinder@infradead.org>

Declaring arch-dependent syscalls for x86 architecture
Signed-off-by: NJaswinder Singh <jaswinder@infradead.org>