uml: throw out CONFIG_MODE_TT

This patchset throws out tt mode, which has been non-functional for a while.

This is done in phases, interspersed with code cleanups on the affected files.

The removal is done as follows:
	remove all code, config options, and files which depend on
CONFIG_MODE_TT
	get rid of the CHOOSE_MODE macro, which decided whether to
call tt-mode or skas-mode code, and replace invocations with their
skas portions
	replace all now-trivial procedures with their skas equivalents

There are now a bunch of now-redundant pieces of data structures, including
mode-specific pieces of the thread structure, pt_regs, and mm_context.  These
are all replaced with their skas-specific contents.

As part of the ongoing style compliance project, I made a style pass over all
files that were changed.  There are three such patches, one for each phase,
covering the files affected by that phase but no later ones.

I noticed that we weren't freeing the LDT state associated with a process when
it exited, so that's fixed in one of the later patches.

The last patch is a tidying patch which I've had for a while, but which caused
inexplicable crashes under tt mode.  Since that is no longer a problem, this
can now go in.

This patch:

Start getting rid of tt mode support.

This patch throws out CONFIG_MODE_TT and all config options, code, and files
which depend on it.

CONFIG_MODE_SKAS is gone and everything that depends on it is included
unconditionally.

The few changed lines are in re-written Kconfig help, lines which needed
something skas-related removed from them, and a few more which weren't
strictly deletions.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-um/processor-generic.h

@@ -34,20 +34,10 @@ struct thread_struct {
 	void *exec_buf;
 	struct arch_thread arch;
 	union {
-#ifdef CONFIG_MODE_TT
-		struct {
-			int extern_pid;
-			int tracing;
-			int switch_pipe[2];
-			int vm_seq;
-		} tt;
-#endif
-#ifdef CONFIG_MODE_SKAS
 		struct {
 			jmp_buf switch_buf;
 			int mm_count;
 		} skas;
-#endif
 	} mode;
 	struct {
 		int op;
@@ -136,12 +126,8 @@ extern struct cpuinfo_um cpu_data[];
 #endif
 
 
-#ifdef CONFIG_MODE_SKAS
 #define KSTK_REG(tsk, reg) \
 	get_thread_reg(reg, &tsk->thread.mode.skas.switch_buf)
-#else
-#define KSTK_REG(tsk, reg) (0xbadbabe)
-#endif
 #define get_wchan(p) (0)
 
 #endif