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authorJeff Dike <jdike@addtoit.com>2007-10-16 12:26:47 +0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 20:43:05 +0400
commit42daba316557e597a90a730f61c762602b7f0e0c (patch)
tree9b7e9da84cef7d2547c577f1cf94b408cf308619 /arch/um/os-Linux/registers.c
parent5c8aaceab88ac787c0a4038b29143c954c2a45e0 (diff)
downloadlinux-42daba316557e597a90a730f61c762602b7f0e0c.tar.xz
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>
Diffstat (limited to 'arch/um/os-Linux/registers.c')
-rw-r--r--arch/um/os-Linux/registers.c54
1 files changed, 54 insertions, 0 deletions
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 <errno.h>
+#include <string.h>
+#include <sys/ptrace.h>
+#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));
+}