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uml: stop saving process FP state

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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>
This commit is contained in:
Jeff Dike
2007-10-16 01:26:47 -07:00
committed by Linus Torvalds
parent 5c8aaceab8
commit 42daba3165
12 changed files with 74 additions and 215 deletions
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2
arch/um/include/os.h
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@@ -307,6 +307,8 @@ extern int protect(struct mm_id * mm_idp, unsigned long addr,
extern int is_skas_winch(int pid, int fd, void *data);
extern int start_userspace(unsigned long stub_stack);
extern int copy_context_skas0(unsigned long stack, int pid);
extern void save_registers(int pid, union uml_pt_regs *regs);
extern void restore_registers(int pid, union uml_pt_regs *regs);
extern void userspace(union uml_pt_regs *regs);
extern void map_stub_pages(int fd, unsigned long code,
unsigned long data, unsigned long stack);