do_device_not_available() is the handler for #NM and it declares that
it takes a unsigned long and calls math_emu(), which takes a long
argument and surprisingly expects the stack frame starting at the zero
argument would match struct math_emu_info, which isn't true regardless
of configuration in the current code.

This patch makes do_device_not_available() take struct pt_regs like
other exception handlers and initialize struct math_emu_info with
pointer to it and pass pointer to the math_emu_info to math_emulate()
like normal C functions do.  This way, unless gcc makes a copy of
struct pt_regs in do_device_not_available(), the register frame is
correctly accessed regardless of kernel configuration or compiler
used.

This doesn't fix all math_emu problems but it at least gets it
somewhat working.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

* Come on, struct info?  s/struct info/struct math_emu_info/

* Use struct pt_regs and kernel_vm86_regs instead of defining its own
  register frame structure.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Before:
total: 6 errors, 1 warnings, 117 lines checked

After:
total: 0 errors, 1 warnings, 117 lines checked

paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/reg_constant.o.*
780388a3056d58fb759efaf190d5d3d1  /tmp/reg_constant.o.after
780388a3056d58fb759efaf190d5d3d1  /tmp/reg_constant.o.before

paolo@paolo-desktop:~/linux.trees.git$ size /tmp/reg_constant.o.*
   text    data     bss     dec     hex filename
    457       0       0     457     1c9 /tmp/reg_constant.o.after
    457       0       0     457     1c9 /tmp/reg_constant.o.before
Signed-off-by: NPaolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix the math emulation that got broken with the recent lazy allocation of FPU
area. init_fpu() need to be added for the math-emulation path aswell
for the FPU area allocation.

math emulation enabled kernel booted fine with this, in the presence
of "no387 nofxsr" boot param.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: hpa@zytor.com
Cc: mingo@elte.hu
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Split the FPU save area from the task struct. This allows easy migration
of FPU context, and it's generally cleaner. It also allows the following
two optimizations:

1) only allocate when the application actually uses FPU, so in the first
lazy FPU trap. This could save memory for non-fpu using apps. Next patch
does this lazy allocation.

2) allocate the right size for the actual cpu rather than 512 bytes always.
Patches enabling xsave/xrstor support (coming shortly) will take advantage
of this.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/math-emu/reg_ld_str.c:380: warning: 'l[0]' may be used uninitialized in this function
arch/x86/math-emu/reg_ld_str.c:380: warning: 'l[1]' may be used uninitialized in this function

I can't actually spot the bug here.  There's one obvious place, but fixing
that didn't shut the warning up.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/math-emu/fpu_entry.c:555: warning: 'entry_sel_off.empty' is used uninitialized in this function

Presumably it's harmless, but I'll sleep better at night knowing that we
initialised it.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/math-emu/errors.c:163: warning: format '%ld' expects type 'long int', but argument 3 has type 'u32'
arch/x86/math-emu/errors.c:175: warning: format '%ld' expects type 'long int', but argument 3 has type 'u32'
arch/x86/math-emu/errors.c:175: warning: format '%ld' expects type 'long int', but argument 4 has type 'u32'
arch/x86/math-emu/errors.c:175: warning: format '%ld' expects type 'long int', but argument 5 has type 'u32'
arch/x86/math-emu/errors.c:175: warning: format '%ld' expects type 'long int', but argument 6 has type 'u32'
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This removes a bunch of dead code that is no longer needed now
that the user_regset interfaces are being used for all these jobs.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This converts the ptrace/signal accessors for i387 math_emu
state to the user_regset interface style, and calls these
from the old interfaces.

It also cleans up math_emulate's ptrace check to be a
single-step check, which is what it really wants.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

manually clean up some of the damage that lindent caused.
(this is a separate commit so that in the unlikely case of
a typo we can bisect it down to the manual edits.)
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

lindent these files:
                                       errors   lines of code   errors/KLOC
 arch/x86/math-emu/                      2236            9424         237.2
 arch/x86/math-emu/                       128            8706          14.7

no other changes. No code changed:

   text    data     bss     dec     hex filename
   5589802  612739 3833856 10036397         9924ad vmlinux.before
   5589802  612739 3833856 10036397         9924ad vmlinux.after

the intent of this patch is to ease the automated tracking of kernel
code quality - it's just much easier for us to maintain it if every file
in arch/x86 is supposed to be clean.

NOTE: it is a known problem of lindent that it causes some style damage
of its own, but it's a safe tool (well, except for the gcc array range
initializers extension), so we did the bulk of the changes via lindent,
and did the manual fixups in a followup patch.

the resulting math-emu code has been tested by Thomas Gleixner on a real
386 DX CPU as well, and it works fine.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Only in very rare cases is it needed to change CFLAGS
outside of arch/*/Makefile.
Fix up all wrong cases - in most cases
the use of EXTRA_CFLAGS is the only thing needed.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>