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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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8
arch/um/os-Linux/skas/process.c
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@ -357,11 +357,10 @@ void userspace(union uml_pt_regs *regs)
}
static unsigned long thread_regs[MAX_REG_NR];
static unsigned long thread_fp_regs[HOST_FP_SIZE];
static int __init init_thread_regs(void)
{
get_safe_registers(thread_regs, thread_fp_regs);
get_safe_registers(thread_regs);
/* Set parent's instruction pointer to start of clone-stub */
thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
(unsigned long) stub_clone_handler -
@ -398,11 +397,6 @@ int copy_context_skas0(unsigned long new_stack, int pid)
panic("copy_context_skas0 : PTRACE_SETREGS failed, "
"pid = %d, errno = %d\n", pid, -err);
err = ptrace_setfpregs(pid, thread_fp_regs);
if(err < 0)
panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
"pid = %d, errno = %d\n", pid, -err);
/* set a well known return code for detection of child write failure */
child_data->err = 12345678;