Commit Graph

3 Commits

Author SHA1 Message Date
Daniel Glöckner
ab9e18587f x86, math-emu: fix init_fpu for task != current
Impact: fix math-emu related crash while using GDB/ptrace

init_fpu() calls finit to initialize a task's xstate, while finit always
works on the current task. If we use PTRACE_GETFPREGS on another
process and both processes did not already use floating point, we get
a null pointer exception in finit.

This patch creates a new function finit_task that takes a task_struct
parameter. finit becomes a wrapper that simply calls finit_task with
current. On the plus side this avoids many calls to get_current which
would each resolve to an inline assembler mov instruction.

An empty finit_task has been added to i387.h to avoid linker errors in
case the compiler still emits the call in init_fpu when
CONFIG_MATH_EMULATION is not defined.

The declaration of finit in i387.h has been removed as the remaining
code using this function gets its prototype from fpu_proto.h.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Bill Metzenthen <billm@melbpc.org.au>
LKML-Reference: <E1Lew31-0004il-Fg@mailer.emlix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-04 20:33:16 +01:00
Ingo Molnar
3d0d14f983 x86: lindent arch/i386/math-emu
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: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:11 +01:00
Thomas Gleixner
da957e111b i386: move math-emu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-11 11:16:31 +02:00