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>

4 files changed, 2 insertions, 113 deletions

diff --git a/arch/um/sys-x86_64/Makefile b/arch/um/sys-x86_64/Makefile
index ea8185d85404..002bb020f96a 100644
--- a/arch/um/sys-x86_64/Makefile
+++ b/arch/um/sys-x86_64/Makefile
@@ -5,10 +5,9 @@
 #
 
 obj-y = bug.o bugs.o delay.o fault.o ldt.o mem.o ptrace.o ptrace_user.o \
-	setjmp.o sigcontext.o signal.o syscalls.o syscall_table.o sysrq.o \
-	ksyms.o tls.o
+	setjmp.o sigcontext.o signal.o stub.o stub_segv.o syscalls.o \
+	syscall_table.o sysrq.o ksyms.o tls.o
 
-obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
 obj-$(CONFIG_MODULES) += um_module.o
 
 subarch-obj-y = lib/bitops_64.o lib/csum-partial_64.o lib/memcpy_64.o lib/thunk_64.o
@@ -21,11 +20,7 @@ USER_OBJS := ptrace_user.o sigcontext.o
 USER_OBJS += user-offsets.s
 extra-y += user-offsets.s
 
-extra-$(CONFIG_MODE_TT) += unmap.o
-
 UNPROFILE_OBJS := stub_segv.o
 CFLAGS_stub_segv.o := $(CFLAGS_NO_HARDENING)
 
 include arch/um/scripts/Makefile.rules
-
-$(obj)/unmap.%: _c_flags = $(call unprofile,$(CFLAGS))
diff --git a/arch/um/sys-x86_64/signal.c b/arch/um/sys-x86_64/signal.c
index fe8ec04d35bb..c18d929e69bc 100644
--- a/arch/um/sys-x86_64/signal.c
+++ b/arch/um/sys-x86_64/signal.c
@@ -15,9 +15,6 @@
 #include "choose-mode.h"
 #include "sysdep/ptrace.h"
 #include "frame_kern.h"
-
-#ifdef CONFIG_MODE_SKAS
-
 #include "skas.h"
 
 void copy_sc(union uml_pt_regs *regs, void *from)
@@ -134,53 +131,6 @@ int copy_sc_to_user_skas(struct sigcontext __user *to,
 	return(err);
 }
 
-#endif
-
-#ifdef CONFIG_MODE_TT
-int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
-			 int fpsize)
-{
-	struct _fpstate *to_fp;
-	struct _fpstate __user *from_fp;
-	unsigned long sigs;
-	int err;
-
-	to_fp = to->fpstate;
-	sigs = to->oldmask;
-	err = copy_from_user(to, from, sizeof(*to));
-	from_fp = to->fpstate;
-	to->fpstate = to_fp;
-	to->oldmask = sigs;
-	if(to_fp != NULL)
-		err |= copy_from_user(to_fp, from_fp, fpsize);
-	return(err);
-}
-
-int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
-		       struct sigcontext *from, int fpsize, unsigned long sp)
-{
-	struct _fpstate __user *to_fp;
-	struct _fpstate *from_fp;
-	int err;
-
-	to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
-	from_fp = from->fpstate;
-	err = copy_to_user(to, from, sizeof(*to));
-	/* The SP in the sigcontext is the updated one for the signal
-	 * delivery.  The sp passed in is the original, and this needs
-	 * to be restored, so we stick it in separately.
-	 */
-	err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
-
-	if(from_fp != NULL){
-		err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
-		err |= copy_to_user(to_fp, from_fp, fpsize);
-	}
-	return err;
-}
-
-#endif
-
 static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 {
        int ret;
diff --git a/arch/um/sys-x86_64/syscalls.c b/arch/um/sys-x86_64/syscalls.c
index b3f6350cac44..d0ff832c9eaf 100644
--- a/arch/um/sys-x86_64/syscalls.c
+++ b/arch/um/sys-x86_64/syscalls.c
@@ -29,36 +29,6 @@ asmlinkage long sys_uname64(struct new_utsname __user * name)
 	return err ? -EFAULT : 0;
 }
 
-#ifdef CONFIG_MODE_TT
-extern long arch_prctl(int code, unsigned long addr);
-
-static long arch_prctl_tt(int code, unsigned long addr)
-{
-	unsigned long tmp;
-	long ret;
-
-	switch(code){
-	case ARCH_SET_GS:
-	case ARCH_SET_FS:
-		ret = arch_prctl(code, addr);
-		break;
-	case ARCH_GET_FS:
-	case ARCH_GET_GS:
-		ret = arch_prctl(code, (unsigned long) &tmp);
-		if(!ret)
-			ret = put_user(tmp, (long __user *)addr);
-		break;
-	default:
-		ret = -EINVAL;
-		break;
-	}
-
-	return(ret);
-}
-#endif
-
-#ifdef CONFIG_MODE_SKAS
-
 long arch_prctl_skas(struct task_struct *task, int code,
                      unsigned long __user *addr)
 {
@@ -119,7 +89,6 @@ long arch_prctl_skas(struct task_struct *task, int code,
 
 	return ret;
 }
-#endif
 
 long sys_arch_prctl(int code, unsigned long addr)
 {
diff --git a/arch/um/sys-x86_64/unmap.c b/arch/um/sys-x86_64/unmap.c
deleted file mode 100644
index f4a4bffd8a18..000000000000
--- a/arch/um/sys-x86_64/unmap.c
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
- * Licensed under the GPL
- */
-
-#include <linux/mman.h>
-#include <asm/unistd.h>
-
-static int errno;
-
-static inline _syscall2(int,munmap,void *,start,size_t,len)
-static inline _syscall6(void *,mmap,void *,addr,size_t,len,int,prot,int,flags,int,fd,off_t,offset)
-int switcheroo(int fd, int prot, void *from, void *to, int size)
-{
-	if(munmap(to, size) < 0){
-		return(-1);
-	}
-	if(mmap(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) == (void*) -1){
-		return(-1);
-	}
-	if(munmap(from, size) < 0){
-		return(-1);
-	}
-	return(0);
-}