x86, mm: fault.c, unify oops handling

Impact: add oops-recursion check to 32-bit

Unify the oops state-machine, to the 64-bit version. It is
slightly more careful in that it does a recursion check
in oops_begin(), and is thus more likely to show the relevant
oops.

It also means that 32-bit will print one more line at the
end of pagefault triggered oopses:

 	printk(KERN_EMERG "CR2: %016lx\n", address);

Which is generally good information to be seen in partial-dump
digital-camera jpegs ;-)

The downside is the somewhat more complex critical path. Both
variants have been tested well meanwhile by kernel developers
crashing their boxes so i dont think this is a practical worry.

This removes 3 ugly #ifdefs from no_context() and makes the
function a lot nicer read.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/fault.c

@@ -659,11 +659,8 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 {
 	struct task_struct *tsk = current;
 	unsigned long *stackend;
-
-#ifdef CONFIG_X86_64
 	unsigned long flags;
 	int sig;
-#endif
 
 	/* Are we prepared to handle this kernel fault? */
 	if (fixup_exception(regs))
@@ -690,11 +687,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 	 * Oops. The kernel tried to access some bad page. We'll have to
 	 * terminate things with extreme prejudice:
 	 */
-#ifdef CONFIG_X86_32
-	bust_spinlocks(1);
-#else
 	flags = oops_begin();
-#endif
 
 	show_fault_oops(regs, error_code, address);
 
@@ -706,11 +699,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 	tsk->thread.trap_no	= 14;
 	tsk->thread.error_code	= error_code;
 
-#ifdef CONFIG_X86_32
-	die("Oops", regs, error_code);
-	bust_spinlocks(0);
-	do_exit(SIGKILL);
-#else
 	sig = SIGKILL;
 	if (__die("Oops", regs, error_code))
 		sig = 0;
@@ -719,7 +707,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 	printk(KERN_EMERG "CR2: %016lx\n", address);
 
 	oops_end(flags, regs, sig);
-#endif
 }
 
 /*