uml: header untangling

Untangle UML headers somewhat and add some includes where they were
needed explicitly, but gotten accidentally via some other header.

arch/um/include/um_uaccess.h loses asm/fixmap.h because it uses no
fixmap stuff and gains elf.h, because it needs FIXADDR_USER_*, and
archsetjmp.h, because it needs jmp_buf.

pmd_alloc_one is uninlined because it needs mm_struct, and that's
inconvenient to provide in asm-um/pgtable-3level.h.

elf_core_copy_fpregs is also uninlined from elf-i386.h and
elf-x86_64.h, which duplicated the code anyway, to
arch/um/kernel/process.c, so that the reference to current_thread
doesn't pull sched.h or anything related into asm/elf.h.

arch/um/sys-i386/ldt.c, arch/um/kernel/tlb.c and
arch/um/kernel/skas/uaccess.c got sched.h because they dereference
task_structs.  Its includes of linux and asm headers got turned from
"" to <>.

arch/um/sys-i386/bug.c gets asm/errno.h because it needs errno
constants.

asm/elf-i386 gets asm/user.h because it needs user_regs_struct.

asm/fixmap.h gets page.h because it needs PAGE_SIZE and PAGE_MASK and
system.h for BUG_ON.

asm/pgtable doesn't need sched.h.

asm/processor-generic.h defined mm_segment_t, but didn't use it.  So,
that definition is moved to uaccess.h, which defines a bunch of
mm_segment_t-related stuff.  thread_info.h uses mm_segment_t, and
includes uaccess.h, which causes a recursion.  So, the definition is
placed above the include of thread_info. in uaccess.h.  thread_info.h
also gets page.h because it needs PAGE_SIZE.

ObCheckpatchViolationJustification - I'm not adding a typedef; I'm
moving mm_segment_t from one place to another.

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>
diff --git a/include/asm-um/elf-i386.h b/include/asm-um/elf-i386.h
index ca94a13..22bbb75 100644
--- a/include/asm-um/elf-i386.h
+++ b/include/asm-um/elf-i386.h
@@ -5,7 +5,7 @@
 #ifndef __UM_ELF_I386_H
 #define __UM_ELF_I386_H
 
-#include <linux/sched.h>
+#include <asm/user.h>
 #include "skas.h"
 
 #define R_386_NONE	0
@@ -76,12 +76,7 @@
 	pr_reg[16] = PT_REGS_SS(regs);		\
 } while(0);
 
-static inline int elf_core_copy_fpregs(struct task_struct *t,
-				       elf_fpregset_t *fpu)
-{
-	int cpu = ((struct thread_info *) t->stack)->cpu;
-	return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);
-}
+extern int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu);
 
 #define ELF_CORE_COPY_FPREGS(t, fpu) elf_core_copy_fpregs(t, fpu)