uml: use ptrace directly in libc code

Some register accessor cleanups -
	userspace() was calling restore_registers and save_registers for no
reason, since userspace() is on the libc side of the house, and these
add no value over calling ptrace directly
	init_thread_registers and get_safe_registers were the same thing,
so init_thread_registers is gone

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>

4 files changed, 13 insertions, 14 deletions

diff --git a/arch/um/include/registers.h b/arch/um/include/registers.h
index 0e27406a43a4..6df37480cb8c 100644
--- a/arch/um/include/registers.h
+++ b/arch/um/include/registers.h
@@ -9,7 +9,6 @@
 #include "sysdep/ptrace.h"
 #include "sysdep/archsetjmp.h"
 
-extern void init_thread_registers(struct uml_pt_regs *to);
 extern int save_fp_registers(int pid, unsigned long *fp_regs);
 extern int restore_fp_registers(int pid, unsigned long *fp_regs);
 extern int save_fpx_registers(int pid, unsigned long *fp_regs);
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index ae1942eeb994..7a291239242b 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -199,7 +199,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
                 arch_copy_thread(&current->thread.arch, &p->thread.arch);
         }
         else {
-                init_thread_registers(&p->thread.regs.regs);
+                get_safe_registers(p->thread.regs.regs.gp);
                 p->thread.request.u.thread = current->thread.request.u.thread;
                 handler = new_thread_handler;
         }
diff --git a/arch/um/os-Linux/registers.c b/arch/um/os-Linux/registers.c
index a32ba6ab1211..c78fae3aba81 100644
--- a/arch/um/os-Linux/registers.c
+++ b/arch/um/os-Linux/registers.c
@@ -10,15 +10,6 @@
 #include "sysdep/ptrace.h"
 #include "user.h"
 
-/* This is set once at boot time and not changed thereafter */
-
-static unsigned long exec_regs[MAX_REG_NR];
-
-void init_thread_registers(struct uml_pt_regs *to)
-{
-        memcpy(to->gp, exec_regs, sizeof(to->gp));
-}
-
 void save_registers(int pid, struct uml_pt_regs *regs)
 {
         int err;
@@ -39,6 +30,10 @@ void restore_registers(int pid, struct uml_pt_regs *regs)
                       "errno = %d\n", errno);
 }
 
+/* This is set once at boot time and not changed thereafter */
+
+static unsigned long exec_regs[MAX_REG_NR];
+
 void init_registers(int pid)
 {
         int err;
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 2cc2071112bc..7dc24e3cb190 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -300,7 +300,9 @@ void userspace(struct uml_pt_regs *regs)
         nsecs += os_nsecs();
 
         while (1) {
-                restore_registers(pid, regs);
+                if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp))
+                        panic("userspace - PTRACE_SETREGS failed, "
+                              "errno = %d\n", errno);
 
                 /* Now we set local_using_sysemu to be used for one loop */
                 local_using_sysemu = get_using_sysemu();
@@ -320,7 +322,10 @@ void userspace(struct uml_pt_regs *regs)
                               errno);
 
                 regs->is_user = 1;
-                save_registers(pid, regs);
+                if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp))
+                        panic("userspace - saving registers failed, "
+                              "errno = %d\n", errno);
+
                 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
 
                 if (WIFSTOPPED(status)) {
@@ -343,7 +348,7 @@ void userspace(struct uml_pt_regs *regs)
                                 break;
                         case SIGVTALRM:
                                 now = os_nsecs();
-                                if(now < nsecs)
+                                if (now < nsecs)
                                         break;
                                 block_signals();
                                 (*sig_info[sig])(sig, regs);