From 42daba316557e597a90a730f61c762602b7f0e0c Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Tue, 16 Oct 2007 01:26:47 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/os-Linux/registers.c | 54 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 arch/um/os-Linux/registers.c (limited to 'arch/um/os-Linux/registers.c') diff --git a/arch/um/os-Linux/registers.c b/arch/um/os-Linux/registers.c new file mode 100644 index 000000000000..9dc3fad9ea29 --- /dev/null +++ b/arch/um/os-Linux/registers.c @@ -0,0 +1,54 @@ +/* + * Copyright (C) 2004 PathScale, Inc + * Licensed under the GPL + */ + +#include +#include +#include +#include "user.h" +#include "sysdep/ptrace.h" + +/* This is set once at boot time and not changed thereafter */ + +static unsigned long exec_regs[MAX_REG_NR]; + +void init_thread_registers(union uml_pt_regs *to) +{ + memcpy(to->skas.regs, exec_regs, sizeof(to->skas.regs)); +} + +void save_registers(int pid, union uml_pt_regs *regs) +{ + int err; + + err = ptrace(PTRACE_GETREGS, pid, 0, regs->skas.regs); + if(err < 0) + panic("save_registers - saving registers failed, errno = %d\n", + errno); +} + +void restore_registers(int pid, union uml_pt_regs *regs) +{ + int err; + + err = ptrace(PTRACE_SETREGS, pid, 0, regs->skas.regs); + if(err < 0) + panic("restore_registers - saving registers failed, " + "errno = %d\n", errno); +} + +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); +} + +void get_safe_registers(unsigned long *regs) +{ + memcpy(regs, exec_regs, sizeof(exec_regs)); +} -- cgit v1.2.1