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>

1 files changed, 1 insertions, 107 deletions

diff --git a/arch/um/os-Linux/sys-i386/registers.c b/arch/um/os-Linux/sys-i386/registers.c
index 84b44f9..f171204 100644
--- a/arch/um/os-Linux/sys-i386/registers.c
+++ b/arch/um/os-Linux/sys-i386/registers.c
@@ -4,30 +4,10 @@
  */
 
 #include <errno.h>
-#include <string.h>
-#include "sysdep/ptrace_user.h"
-#include "sysdep/ptrace.h"
-#include "uml-config.h"
-#include "skas_ptregs.h"
-#include "registers.h"
+#include <sysdep/ptrace_user.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];
-static unsigned long exec_fpx_regs[HOST_XFP_SIZE];
-static int have_fpx_regs = 1;
-
-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));
-	if(have_fpx_regs)
-		memcpy(to->skas.xfp, exec_fpx_regs, sizeof(to->skas.xfp));
-}
-
 /* XXX These need to use [GS]ETFPXREGS and copy_sc_{to,from}_user_skas needs
  * to pass in a sufficiently large buffer
  */
@@ -45,92 +25,6 @@ int restore_fp_registers(int pid, unsigned long *fp_regs)
 	return 0;
 }
 
-static int move_registers(int pid, int int_op, union uml_pt_regs *regs,
-			  int fp_op, unsigned long *fp_regs)
-{
-	if(ptrace(int_op, pid, 0, regs->skas.regs) < 0)
-		return -errno;
-
-	if(ptrace(fp_op, pid, 0, fp_regs) < 0)
-		return -errno;
-
-	return 0;
-}
-
-void save_registers(int pid, union uml_pt_regs *regs)
-{
-	unsigned long *fp_regs;
-	int err, fp_op;
-
-	if(have_fpx_regs){
-		fp_op = PTRACE_GETFPXREGS;
-		fp_regs = regs->skas.xfp;
-	}
-	else {
-		fp_op = PTRACE_GETFPREGS;
-		fp_regs = regs->skas.fp;
-	}
-
-	err = move_registers(pid, PTRACE_GETREGS, regs, fp_op, fp_regs);
-	if(err)
-		panic("save_registers - saving registers failed, errno = %d\n",
-		      -err);
-}
-
-void restore_registers(int pid, union uml_pt_regs *regs)
-{
-	unsigned long *fp_regs;
-	int err, fp_op;
-
-	if(have_fpx_regs){
-		fp_op = PTRACE_SETFPXREGS;
-		fp_regs = regs->skas.xfp;
-	}
-	else {
-		fp_op = PTRACE_SETFPREGS;
-		fp_regs = regs->skas.fp;
-	}
-
-	err = move_registers(pid, PTRACE_SETREGS, regs, fp_op, fp_regs);
-	if(err)
-		panic("restore_registers - saving registers failed, "
-		      "errno = %d\n", -err);
-}
-
-void init_registers(int pid)
-{
-	int err;
-
-	memset(exec_regs, 0, sizeof(exec_regs));
-	err = ptrace(PTRACE_GETREGS, pid, 0, exec_regs);
-	if(err)
-		panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",
-		      errno);
-
-	errno = 0;
-	err = ptrace(PTRACE_GETFPXREGS, pid, 0, exec_fpx_regs);
-	if(!err)
-		return;
-	if(errno != EIO)
-		panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d",
-		      errno);
-
-	have_fpx_regs = 0;
-
-	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){