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: Brian Gerst <brgerst@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
On x86_32, %gs is handled lazily. It's not saved and restored on
kernel entry/exit but only when necessary which usually is during task
switch but there are few other places. Currently, it's done by
calling savesegment() and loadsegment() explicitly. Define
get_user_gs(), set_user_gs() and task_user_gs() and use them instead.
While at it, clean up register access macros in signal.c.
This cleans up code a bit and will help future changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: use new framework
Use {get|put}_user_try, catch, and _ex in arch/x86/kernel/signal.c.
Note: this patch contains "WARNING: line over 80 characters", because when
introducing new block I insert an indent to avoid mistakes by edit.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This reverts commit 4217458daf.
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=12505
Reported-and-bisected-by: Justin Madru <jdm64@gawab.com>
Tested-by: Justin Madru <jdm64@gawab.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, move header file
Move arch/x86/kernel/sigframe.h to arch/x86/include/asm/sigframe.h.
It will be used in arch/x86/ia32/ia32_signal.c.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Move declarations of ia32_setup_rt_frame() and ia32_setup_frame() into
arch/x86/kernel/signal.c.
This is for future use of sigframe.h.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Call signal_fault() in error route of sys_sigreturn().
Change log level to KERN_EMERG if current is init.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup on 32-bit
Peter pointed this parameter can be changed.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Brian Gerst