uml: stop saving process FP state

Throw out a lot of code dealing with saving and restoring floating-point
state.  In skas mode, where processes run in a restoring floating-point state
on kernel entry and exit is pointless.

This eliminates most of arch/um/os-Linux/sys-{i386,x86_64}/registers.c.  Most
of what remained is now arch-indpendent, and can be moved up to
arch/um/os-Linux/registers.c.  Both arches need the jmp_buf accessor
get_thread_reg, and i386 needs {save,restore}_fp_regs because it cheats during
sigreturn by getting the fp state using ptrace rather than copying it out of
the process sigcontext.

After this, it turns out that arch/um/include/skas/mode-skas.h is almost
completely unneeded.  The declarations in it are variables which either don't
exist or which don't have global scope.  The one exception is
kill_off_processes_skas.  If that's removed, this header can be deleted.

This uncovered a bug in user.h, which wasn't correctly making sure that a
size_t definition was available to both userspace and kernelspace files.

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>

2 files changed, 4 insertions, 73 deletions

diff --git a/arch/um/os-Linux/sys-x86_64/Makefile b/arch/um/os-Linux/sys-x86_64/Makefile
index 7955e061a678..eac8c0db3001 100644
--- a/arch/um/os-Linux/sys-x86_64/Makefile
+++ b/arch/um/os-Linux/sys-x86_64/Makefile
@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
+# Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 # Licensed under the GPL
 #
 
diff --git a/arch/um/os-Linux/sys-x86_64/registers.c b/arch/um/os-Linux/sys-x86_64/registers.c
index 9467315b8059..9bfa789992de 100644
--- a/arch/um/os-Linux/sys-x86_64/registers.c
+++ b/arch/um/os-Linux/sys-x86_64/registers.c
@@ -1,23 +1,15 @@
 /*
- * Copyright (C) 2004 PathScale, Inc
+ * Copyright (C) 2006-2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
 #include <errno.h>
 #include <sys/ptrace.h>
-#include <string.h>
-#include "ptrace_user.h"
-#include "uml-config.h"
-#include "skas_ptregs.h"
-#include "registers.h"
+#define __FRAME_OFFSETS
+#include <asm/ptrace.h>
 #include "longjmp.h"
 #include "user.h"
 
-/* These are set once at boot time and not changed thereafter */
-
-static unsigned long exec_regs[MAX_REG_NR];
-static unsigned long exec_fp_regs[HOST_FP_SIZE];
-
 int save_fp_registers(int pid, unsigned long *fp_regs)
 {
         if(ptrace(PTRACE_GETFPREGS, pid, 0, fp_regs) < 0)
@@ -32,67 +24,6 @@ int restore_fp_registers(int pid, unsigned long *fp_regs)
         return 0;
 }
 
-void init_thread_registers(union uml_pt_regs *to)
-{
-        memcpy(to->skas.regs, exec_regs, sizeof(to->skas.regs));
-        memcpy(to->skas.fp, exec_fp_regs, sizeof(to->skas.fp));
-}
-
-static int move_registers(int pid, int int_op, int fp_op,
-                          union uml_pt_regs *regs)
-{
-        if(ptrace(int_op, pid, 0, regs->skas.regs) < 0)
-                return -errno;
-
-        if(ptrace(fp_op, pid, 0, regs->skas.fp) < 0)
-                return -errno;
-
-        return 0;
-}
-
-void save_registers(int pid, union uml_pt_regs *regs)
-{
-        int err;
-
-        err = move_registers(pid, PTRACE_GETREGS, PTRACE_GETFPREGS, regs);
-        if(err)
-                panic("save_registers - saving registers failed, errno = %d\n",
-                      -err);
-}
-
-void restore_registers(int pid, union uml_pt_regs *regs)
-{
-        int err;
-
-        err = move_registers(pid, PTRACE_SETREGS, PTRACE_SETFPREGS, regs);
-        if(err)
-                panic("restore_registers - saving registers failed, "
-                      "errno = %d\n", -err);
-}
-
-void init_registers(int pid)
-{
-        int err;
-
-        err = ptrace(PTRACE_GETREGS, pid, 0, exec_regs);
-        if(err)
-                panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",
-                      errno);
-
-        err = ptrace(PTRACE_GETFPREGS, pid, 0, exec_fp_regs);
-        if(err)
-                panic("check_ptrace : PTRACE_GETFPREGS failed, errno = %d",
-                      errno);
-}
-
-void get_safe_registers(unsigned long *regs, unsigned long *fp_regs)
-{
-        memcpy(regs, exec_regs, sizeof(exec_regs));
-        if(fp_regs != NULL)
-                memcpy(fp_regs, exec_fp_regs,
-                       HOST_FP_SIZE * sizeof(unsigned long));
-}
-
 unsigned long get_thread_reg(int reg, jmp_buf *buf)
 {
         switch(reg){