1 files changed, 371 insertions, 227 deletions

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index ba9af8d6205..908579f2b0a 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -1,64 +1,46 @@
 /*
- * Copyright (C) 2002- 2004 Jeff Dike (jdike@addtoit.com)
+ * Copyright (C) 2002- 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
-#include <errno.h>
-#include <signal.h>
 #include <sched.h>
-#include "ptrace_user.h"
-#include <sys/wait.h>
+#include <errno.h>
+#include <string.h>
 #include <sys/mman.h>
-#include <sys/user.h>
-#include <sys/time.h>
-#include <sys/syscall.h>
-#include <asm/types.h>
-#include "user.h"
-#include "sysdep/ptrace.h"
-#include "kern_util.h"
-#include "skas.h"
-#include "stub-data.h"
-#include "mm_id.h"
-#include "sysdep/sigcontext.h"
-#include "sysdep/stub.h"
-#include "os.h"
-#include "proc_mm.h"
-#include "skas_ptrace.h"
-#include "chan_user.h"
-#include "registers.h"
-#include "mem.h"
-#include "uml-config.h"
-#include "process.h"
-#include "longjmp.h"
-#include "kern_constants.h"
-#include "as-layout.h"
+#include <sys/wait.h>
+#include <asm/unistd.h>
+#include <as-layout.h>
+#include <init.h>
+#include <kern_util.h>
+#include <mem.h>
+#include <os.h>
+#include <proc_mm.h>
+#include <ptrace_user.h>
+#include <registers.h>
+#include <skas.h>
+#include <skas_ptrace.h>
+#include <sysdep/stub.h>
 
 int is_skas_winch(int pid, int fd, void *data)
 {
-	if(pid != os_getpgrp())
-		return(0);
-
-	register_winch_irq(-1, fd, -1, data, 0);
-	return(1);
+	return pid == getpgrp();
 }
 
 static int ptrace_dump_regs(int pid)
 {
-        unsigned long regs[MAX_REG_NR];
-        int i;
-
-        if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
-                return -errno;
-        else {
-                printk("Stub registers -\n");
-                for(i = 0; i < ARRAY_SIZE(regs); i++)
-                        printk("\t%d - %lx\n", i, regs[i]);
-        }
-
-        return 0;
+	unsigned long regs[MAX_REG_NR];
+	int i;
+
+	if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
+		return -errno;
+
+	printk(UM_KERN_ERR "Stub registers -\n");
+	for (i = 0; i < ARRAY_SIZE(regs); i++)
+		printk(UM_KERN_ERR "\t%d - %lx\n", i, regs[i]);
+
+	return 0;
 }
 
 /*
@@ -68,48 +50,55 @@ static int ptrace_dump_regs(int pid)
 #define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
 
 /* Signals that the stub will finish with - anything else is an error */
-#define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP))
+#define STUB_DONE_MASK (1 << SIGTRAP)
 
 void wait_stub_done(int pid)
 {
 	int n, status, err;
 
-	while(1){
-		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
-		if((n < 0) || !WIFSTOPPED(status))
+	while (1) {
+		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
+		if ((n < 0) || !WIFSTOPPED(status))
 			goto bad_wait;
 
-		if(((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
+		if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
 			break;
 
 		err = ptrace(PTRACE_CONT, pid, 0, 0);
-		if(err)
-			panic("wait_stub_done : continue failed, errno = %d\n",
-			      errno);
+		if (err) {
+			printk(UM_KERN_ERR "wait_stub_done : continue failed, "
+			       "errno = %d\n", errno);
+			fatal_sigsegv();
+		}
 	}
 
-	if(((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
+	if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
 		return;
 
 bad_wait:
 	err = ptrace_dump_regs(pid);
-	if(err)
-		printk("Failed to get registers from stub, errno = %d\n", -err);
-	panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, "
-	      "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status);
+	if (err)
+		printk(UM_KERN_ERR "Failed to get registers from stub, "
+		       "errno = %d\n", -err);
+	printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, "
+	       "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno,
+	       status);
+	fatal_sigsegv();
 }
 
 extern unsigned long current_stub_stack(void);
 
-void get_skas_faultinfo(int pid, struct faultinfo * fi)
+static void get_skas_faultinfo(int pid, struct faultinfo *fi)
 {
 	int err;
 
-	if(ptrace_faultinfo){
+	if (ptrace_faultinfo) {
 		err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
-		if(err)
-			panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
-			      "errno = %d\n", errno);
+		if (err) {
+			printk(UM_KERN_ERR "get_skas_faultinfo - "
+			       "PTRACE_FAULTINFO failed, errno = %d\n", errno);
+			fatal_sigsegv();
+		}
 
 		/* Special handling for i386, which has different structs */
 		if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
@@ -118,56 +107,87 @@ void get_skas_faultinfo(int pid, struct faultinfo * fi)
 			       sizeof(struct ptrace_faultinfo));
 	}
 	else {
+		unsigned long fpregs[FP_SIZE];
+
+		err = get_fp_registers(pid, fpregs);
+		if (err < 0) {
+			printk(UM_KERN_ERR "save_fp_registers returned %d\n",
+			       err);
+			fatal_sigsegv();
+		}
 		err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
-		if(err)
-			panic("Failed to continue stub, pid = %d, errno = %d\n",
-			      pid, errno);
+		if (err) {
+			printk(UM_KERN_ERR "Failed to continue stub, pid = %d, "
+			       "errno = %d\n", pid, errno);
+			fatal_sigsegv();
+		}
 		wait_stub_done(pid);
 
-		/* faultinfo is prepared by the stub-segv-handler at start of
+		/*
+		 * faultinfo is prepared by the stub-segv-handler at start of
 		 * the stub stack page. We just have to copy it.
 		 */
 		memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
+
+		err = put_fp_registers(pid, fpregs);
+		if (err < 0) {
+			printk(UM_KERN_ERR "put_fp_registers returned %d\n",
+			       err);
+			fatal_sigsegv();
+		}
 	}
 }
 
-static void handle_segv(int pid, union uml_pt_regs * regs)
+static void handle_segv(int pid, struct uml_pt_regs * regs)
 {
-	get_skas_faultinfo(pid, &regs->skas.faultinfo);
-	segv(regs->skas.faultinfo, 0, 1, NULL);
+	get_skas_faultinfo(pid, &regs->faultinfo);
+	segv(regs->faultinfo, 0, 1, NULL);
 }
 
-/*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
-static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
+/*
+ * To use the same value of using_sysemu as the caller, ask it that value
+ * (in local_using_sysemu
+ */
+static void handle_trap(int pid, struct uml_pt_regs *regs,
+			int local_using_sysemu)
 {
 	int err, status;
 
+	if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
+		fatal_sigsegv();
+
 	/* Mark this as a syscall */
-	UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
+	UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp);
 
 	if (!local_using_sysemu)
 	{
-		err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
+		err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
 			     __NR_getpid);
-		if(err < 0)
-			panic("handle_trap - nullifying syscall failed errno = %d\n",
-			      errno);
+		if (err < 0) {
+			printk(UM_KERN_ERR "handle_trap - nullifying syscall "
+			       "failed, errno = %d\n", errno);
+			fatal_sigsegv();
+		}
 
 		err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
-		if(err < 0)
-			panic("handle_trap - continuing to end of syscall failed, "
-			      "errno = %d\n", errno);
-
-		CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
-		if((err < 0) || !WIFSTOPPED(status) ||
-		   (WSTOPSIG(status) != SIGTRAP + 0x80)){
-                        err = ptrace_dump_regs(pid);
-                        if(err)
-                                printk("Failed to get registers from process, "
-                                       "errno = %d\n", -err);
-			panic("handle_trap - failed to wait at end of syscall, "
-			      "errno = %d, status = %d\n", errno, status);
-                }
+		if (err < 0) {
+			printk(UM_KERN_ERR "handle_trap - continuing to end of "
+			       "syscall failed, errno = %d\n", errno);
+			fatal_sigsegv();
+		}
+
+		CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
+		if ((err < 0) || !WIFSTOPPED(status) ||
+		    (WSTOPSIG(status) != SIGTRAP + 0x80)) {
+			err = ptrace_dump_regs(pid);
+			if (err)
+				printk(UM_KERN_ERR "Failed to get registers "
+				       "from process, errno = %d\n", -err);
+			printk(UM_KERN_ERR "handle_trap - failed to wait at "
+			       "end of syscall, errno = %d, status = %d\n",
+			       errno, status);
+			fatal_sigsegv();
+		}
 	}
 
 	handle_syscall(regs);
@@ -182,63 +202,65 @@ static int userspace_tramp(void *stack)
 
 	ptrace(PTRACE_TRACEME, 0, 0, 0);
 
-	init_new_thread_signals();
-	err = set_interval(1);
-	if(err)
-		panic("userspace_tramp - setting timer failed, errno = %d\n",
-		      err);
+	signal(SIGTERM, SIG_DFL);
+	signal(SIGWINCH, SIG_IGN);
+	err = set_interval();
+	if (err) {
+		printk(UM_KERN_ERR "userspace_tramp - setting timer failed, "
+		       "errno = %d\n", err);
+		exit(1);
+	}
 
-	if(!proc_mm){
-		/* This has a pte, but it can't be mapped in with the usual
+	if (!proc_mm) {
+		/*
+		 * This has a pte, but it can't be mapped in with the usual
 		 * tlb_flush mechanism because this is part of that mechanism
 		 */
 		int fd;
-		__u64 offset;
+		unsigned long long offset;
 		fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
-		addr = mmap64((void *) UML_CONFIG_STUB_CODE, UM_KERN_PAGE_SIZE,
+		addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
 			      PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
-		if(addr == MAP_FAILED){
-			printk("mapping mmap stub failed, errno = %d\n",
-			       errno);
+		if (addr == MAP_FAILED) {
+			printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
+			       "errno = %d\n", STUB_CODE, errno);
 			exit(1);
 		}
 
-		if(stack != NULL){
+		if (stack != NULL) {
 			fd = phys_mapping(to_phys(stack), &offset);
-			addr = mmap((void *) UML_CONFIG_STUB_DATA,
+			addr = mmap((void *) STUB_DATA,
 				    UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
 				    MAP_FIXED | MAP_SHARED, fd, offset);
-			if(addr == MAP_FAILED){
-				printk("mapping segfault stack failed, "
-				       "errno = %d\n", errno);
+			if (addr == MAP_FAILED) {
+				printk(UM_KERN_ERR "mapping segfault stack "
+				       "at 0x%lx failed, errno = %d\n",
+				       STUB_DATA, errno);
 				exit(1);
 			}
 		}
 	}
-	if(!ptrace_faultinfo && (stack != NULL)){
+	if (!ptrace_faultinfo && (stack != NULL)) {
 		struct sigaction sa;
 
-		unsigned long v = UML_CONFIG_STUB_CODE +
+		unsigned long v = STUB_CODE +
 				  (unsigned long) stub_segv_handler -
 				  (unsigned long) &__syscall_stub_start;
 
-		set_sigstack((void *) UML_CONFIG_STUB_DATA, UM_KERN_PAGE_SIZE);
+		set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
 		sigemptyset(&sa.sa_mask);
-		sigaddset(&sa.sa_mask, SIGIO);
-		sigaddset(&sa.sa_mask, SIGWINCH);
-		sigaddset(&sa.sa_mask, SIGALRM);
-		sigaddset(&sa.sa_mask, SIGVTALRM);
-		sigaddset(&sa.sa_mask, SIGUSR1);
-		sa.sa_flags = SA_ONSTACK;
-		sa.sa_handler = (void *) v;
+		sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
+		sa.sa_sigaction = (void *) v;
 		sa.sa_restorer = NULL;
-		if(sigaction(SIGSEGV, &sa, NULL) < 0)
-			panic("userspace_tramp - setting SIGSEGV handler "
-			      "failed - errno = %d\n", errno);
+		if (sigaction(SIGSEGV, &sa, NULL) < 0) {
+			printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV "
+			       "handler failed - errno = %d\n", errno);
+			exit(1);
+		}
 	}
 
-	os_stop_process(os_getpid());
-	return(0);
+	kill(os_getpid(), SIGSTOP);
+	return 0;
 }
 
 /* Each element set once, and only accessed by a single processor anyway */
@@ -250,50 +272,105 @@ int start_userspace(unsigned long stub_stack)
 {
 	void *stack;
 	unsigned long sp;
-	int pid, status, n, flags;
+	int pid, status, n, flags, err;
 
 	stack = mmap(NULL, UM_KERN_PAGE_SIZE,
 		     PROT_READ | PROT_WRITE | PROT_EXEC,
 		     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-	if(stack == MAP_FAILED)
-		panic("start_userspace : mmap failed, errno = %d", errno);
+	if (stack == MAP_FAILED) {
+		err = -errno;
+		printk(UM_KERN_ERR "start_userspace : mmap failed, "
+		       "errno = %d\n", errno);
+		return err;
+	}
+
 	sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
 
-	flags = CLONE_FILES | SIGCHLD;
-	if(proc_mm) flags |= CLONE_VM;
+	flags = CLONE_FILES;
+	if (proc_mm)
+		flags |= CLONE_VM;
+	else
+		flags |= SIGCHLD;
+
 	pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
-	if(pid < 0)
-		panic("start_userspace : clone failed, errno = %d", errno);
+	if (pid < 0) {
+		err = -errno;
+		printk(UM_KERN_ERR "start_userspace : clone failed, "
+		       "errno = %d\n", errno);
+		return err;
+	}
 
 	do {
-		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
-		if(n < 0)
-			panic("start_userspace : wait failed, errno = %d",
-			      errno);
-	} while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
+		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
+		if (n < 0) {
+			err = -errno;
+			printk(UM_KERN_ERR "start_userspace : wait failed, "
+			       "errno = %d\n", errno);
+			goto out_kill;
+		}
+	} while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
+
+	if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
+		err = -EINVAL;
+		printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got "
+		       "status = %d\n", status);
+		goto out_kill;
+	}
 
-	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
-		panic("start_userspace : expected SIGSTOP, got status = %d",
-		      status);
+	if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
+		   (void *) PTRACE_O_TRACESYSGOOD) < 0) {
+		err = -errno;
+		printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS "
+		       "failed, errno = %d\n", errno);
+		goto out_kill;
+	}
 
-	if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0)
-		panic("start_userspace : PTRACE_OLDSETOPTIONS failed, errno=%d\n",
-		      errno);
+	if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) {
+		err = -errno;
+		printk(UM_KERN_ERR "start_userspace : munmap failed, "
+		       "errno = %d\n", errno);
+		goto out_kill;
+	}
 
-	if(munmap(stack, UM_KERN_PAGE_SIZE) < 0)
-		panic("start_userspace : munmap failed, errno = %d\n", errno);
+	return pid;
 
-	return(pid);
+ out_kill:
+	os_kill_ptraced_process(pid, 1);
+	return err;
 }
 
-void userspace(union uml_pt_regs *regs)
+void userspace(struct uml_pt_regs *regs)
 {
+	struct itimerval timer;
+	unsigned long long nsecs, now;
 	int err, status, op, pid = userspace_pid[0];
 	/* To prevent races if using_sysemu changes under us.*/
 	int local_using_sysemu;
+	siginfo_t si;
+
+	/* Handle any immediate reschedules or signals */
+	interrupt_end();
+
+	if (getitimer(ITIMER_VIRTUAL, &timer))
+		printk(UM_KERN_ERR "Failed to get itimer, errno = %d\n", errno);
+	nsecs = timer.it_value.tv_sec * UM_NSEC_PER_SEC +
+		timer.it_value.tv_usec * UM_NSEC_PER_USEC;
+	nsecs += os_nsecs();
+
+	while (1) {
+		/*
+		 * This can legitimately fail if the process loads a
+		 * bogus value into a segment register.  It will
+		 * segfault and PTRACE_GETREGS will read that value
+		 * out of the process.  However, PTRACE_SETREGS will
+		 * fail.  In this case, there is nothing to do but
+		 * just kill the process.
+		 */
+		if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp))
+			fatal_sigsegv();
 
-	while(1){
-		restore_registers(pid, regs);
+		if (put_fp_registers(pid, regs->fp))
+			fatal_sigsegv();
 
 		/* Now we set local_using_sysemu to be used for one loop */
 		local_using_sysemu = get_using_sysemu();
@@ -301,28 +378,47 @@ void userspace(union uml_pt_regs *regs)
 		op = SELECT_PTRACE_OPERATION(local_using_sysemu,
 					     singlestepping(NULL));
 
-		err = ptrace(op, pid, 0, 0);
-		if(err)
-			panic("userspace - could not resume userspace process, "
-			      "pid=%d, ptrace operation = %d, errno = %d\n",
-			      pid, op, errno);
+		if (ptrace(op, pid, 0, 0)) {
+			printk(UM_KERN_ERR "userspace - ptrace continue "
+			       "failed, op = %d, errno = %d\n", op, errno);
+			fatal_sigsegv();
+		}
+
+		CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
+		if (err < 0) {
+			printk(UM_KERN_ERR "userspace - wait failed, "
+			       "errno = %d\n", errno);
+			fatal_sigsegv();
+		}
+
+		regs->is_user = 1;
+		if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) {
+			printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, "
+			       "errno = %d\n", errno);
+			fatal_sigsegv();
+		}
 
-		CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
-		if(err < 0)
-			panic("userspace - waitpid failed, errno = %d\n",
-			      errno);
+		if (get_fp_registers(pid, regs->fp)) {
+			printk(UM_KERN_ERR "userspace -  get_fp_registers failed, "
+			       "errno = %d\n", errno);
+			fatal_sigsegv();
+		}
 
-		regs->skas.is_user = 1;
-		save_registers(pid, regs);
 		UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
 
-		if(WIFSTOPPED(status)){
+		if (WIFSTOPPED(status)) {
 			int sig = WSTOPSIG(status);
-		  	switch(sig){
+
+			ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si);
+
+			switch (sig) {
 			case SIGSEGV:
-				if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo){
-					get_skas_faultinfo(pid, &regs->skas.faultinfo);
-					(*sig_info[SIGSEGV])(SIGSEGV, regs);
+				if (PTRACE_FULL_FAULTINFO ||
+				    !ptrace_faultinfo) {
+					get_skas_faultinfo(pid,
+							   &regs->faultinfo);
+					(*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
+							     regs);
 				}
 				else handle_segv(pid, regs);
 				break;
@@ -330,43 +426,56 @@ void userspace(union uml_pt_regs *regs)
 			        handle_trap(pid, regs, local_using_sysemu);
 				break;
 			case SIGTRAP:
-				relay_signal(SIGTRAP, regs);
+				relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
 				break;
-			case SIGIO:
 			case SIGVTALRM:
+				now = os_nsecs();
+				if (now < nsecs)
+					break;
+				block_signals();
+				(*sig_info[sig])(sig, (struct siginfo *)&si, regs);
+				unblock_signals();
+				nsecs = timer.it_value.tv_sec *
+					UM_NSEC_PER_SEC +
+					timer.it_value.tv_usec *
+					UM_NSEC_PER_USEC;
+				nsecs += os_nsecs();
+				break;
+			case SIGIO:
 			case SIGILL:
 			case SIGBUS:
 			case SIGFPE:
 			case SIGWINCH:
 				block_signals();
-				(*sig_info[sig])(sig, regs);
+				(*sig_info[sig])(sig, (struct siginfo *)&si, regs);
 				unblock_signals();
 				break;
 			default:
-			        printk("userspace - child stopped with signal "
-				       "%d\n", sig);
+				printk(UM_KERN_ERR "userspace - child stopped "
+				       "with signal %d\n", sig);
+				fatal_sigsegv();
 			}
 			pid = userspace_pid[0];
 			interrupt_end();
 
 			/* Avoid -ERESTARTSYS handling in host */
-			if(PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
-				PT_SYSCALL_NR(regs->skas.regs) = -1;
+			if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
+				PT_SYSCALL_NR(regs->gp) = -1;
 		}
 	}
 }
 
 static unsigned long thread_regs[MAX_REG_NR];
-static unsigned long thread_fp_regs[HOST_FP_SIZE];
+static unsigned long thread_fp_regs[FP_SIZE];
 
 static int __init init_thread_regs(void)
 {
 	get_safe_registers(thread_regs, thread_fp_regs);
 	/* Set parent's instruction pointer to start of clone-stub */
-	thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+	thread_regs[REGS_IP_INDEX] = STUB_CODE +
 				(unsigned long) stub_clone_handler -
 				(unsigned long) &__syscall_stub_start;
-	thread_regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + UM_KERN_PAGE_SIZE -
+	thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
 		sizeof(void *);
 #ifdef __SIGNAL_FRAMESIZE
 	thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
@@ -378,62 +487,88 @@ __initcall(init_thread_regs);
 
 int copy_context_skas0(unsigned long new_stack, int pid)
 {
+	struct timeval tv = { .tv_sec = 0, .tv_usec = UM_USEC_PER_SEC / UM_HZ };
 	int err;
 	unsigned long current_stack = current_stub_stack();
 	struct stub_data *data = (struct stub_data *) current_stack;
 	struct stub_data *child_data = (struct stub_data *) new_stack;
-	__u64 new_offset;
+	unsigned long long new_offset;
 	int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
 
-	/* prepare offset and fd of child's stack as argument for parent's
+	/*
+	 * prepare offset and fd of child's stack as argument for parent's
 	 * and child's mmap2 calls
 	 */
 	*data = ((struct stub_data) { .offset	= MMAP_OFFSET(new_offset),
 				      .fd	= new_fd,
 				      .timer    = ((struct itimerval)
-					            { { 0, 1000000 / hz() },
-						      { 0, 1000000 / hz() }})});
+					           { .it_value = tv,
+						     .it_interval = tv }) });
+
 	err = ptrace_setregs(pid, thread_regs);
-	if(err < 0)
-		panic("copy_context_skas0 : PTRACE_SETREGS failed, "
-		      "pid = %d, errno = %d\n", pid, -err);
+	if (err < 0) {
+		err = -errno;
+		printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS "
+		       "failed, pid = %d, errno = %d\n", pid, -err);
+		return 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);
+	err = put_fp_registers(pid, thread_fp_regs);
+	if (err < 0) {
+		printk(UM_KERN_ERR "copy_context_skas0 : put_fp_registers "
+		       "failed, pid = %d, err = %d\n", pid, err);
+		return err;
+	}
 
 	/* set a well known return code for detection of child write failure */
 	child_data->err = 12345678;
 
-	/* Wait, until parent has finished its work: read child's pid from
+	/*
+	 * Wait, until parent has finished its work: read child's pid from
 	 * parent's stack, and check, if bad result.
 	 */
 	err = ptrace(PTRACE_CONT, pid, 0, 0);
-	if(err)
-		panic("Failed to continue new process, pid = %d, "
-		      "errno = %d\n", pid, errno);
+	if (err) {
+		err = -errno;
+		printk(UM_KERN_ERR "Failed to continue new process, pid = %d, "
+		       "errno = %d\n", pid, errno);
+		return err;
+	}
+
 	wait_stub_done(pid);
 
 	pid = data->err;
-	if(pid < 0)
-		panic("copy_context_skas0 - stub-parent reports error %d\n",
-		      -pid);
+	if (pid < 0) {
+		printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports "
+		       "error %d\n", -pid);
+		return pid;
+	}
 
-	/* Wait, until child has finished too: read child's result from
+	/*
+	 * Wait, until child has finished too: read child's result from
 	 * child's stack and check it.
 	 */
 	wait_stub_done(pid);
-	if (child_data->err != UML_CONFIG_STUB_DATA)
-		panic("copy_context_skas0 - stub-child reports error %ld\n",
-		      child_data->err);
+	if (child_data->err != STUB_DATA) {
+		printk(UM_KERN_ERR "copy_context_skas0 - stub-child reports "
+		       "error %ld\n", child_data->err);
+		err = child_data->err;
+		goto out_kill;
+	}
 
 	if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
-		   (void *)PTRACE_O_TRACESYSGOOD) < 0)
-		panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, "
-		      "errno = %d\n", errno);
+		   (void *)PTRACE_O_TRACESYSGOOD) < 0) {
+		err = -errno;
+		printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS "
+		       "failed, errno = %d\n", errno);
+		goto out_kill;
+	}
 
 	return pid;
+
+ out_kill:
+	os_kill_ptraced_process(pid, 1);
+	return err;
 }
 
 /*
@@ -441,12 +576,12 @@ int copy_context_skas0(unsigned long new_stack, int pid)
  * available. Opening /proc/mm creates a new mm_context, which lacks
  * the stub-pages. Thus, we map them using /proc/mm-fd
  */
-void map_stub_pages(int fd, unsigned long code,
-		    unsigned long data, unsigned long stack)
+int map_stub_pages(int fd, unsigned long code, unsigned long data,
+		   unsigned long stack)
 {
 	struct proc_mm_op mmop;
 	int n;
-	__u64 code_offset;
+	unsigned long long code_offset;
 	int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
 				   &code_offset);
 
@@ -461,16 +596,18 @@ void map_stub_pages(int fd, unsigned long code,
 					  .offset  = code_offset
 	} } });
 	CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
-	if(n != sizeof(mmop)){
+	if (n != sizeof(mmop)) {
 		n = errno;
-		printk("mmap args - addr = 0x%lx, fd = %d, offset = %llx\n",
-		       code, code_fd, (unsigned long long) code_offset);
-		panic("map_stub_pages : /proc/mm map for code failed, "
-		      "err = %d\n", n);
+		printk(UM_KERN_ERR "mmap args - addr = 0x%lx, fd = %d, "
+		       "offset = %llx\n", code, code_fd,
+		       (unsigned long long) code_offset);
+		printk(UM_KERN_ERR "map_stub_pages : /proc/mm map for code "
+		       "failed, err = %d\n", n);
+		return -n;
 	}
 
-	if ( stack ) {
-		__u64 map_offset;
+	if (stack) {
+		unsigned long long map_offset;
 		int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
 		mmop = ((struct proc_mm_op)
 				{ .op        = MM_MMAP,
@@ -484,10 +621,15 @@ void map_stub_pages(int fd, unsigned long code,
 				      .offset  = map_offset
 		} } });
 		CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
-		if(n != sizeof(mmop))
-			panic("map_stub_pages : /proc/mm map for data failed, "
-			      "err = %d\n", errno);
+		if (n != sizeof(mmop)) {
+			n = errno;
+			printk(UM_KERN_ERR "map_stub_pages : /proc/mm map for "
+			       "data failed, err = %d\n", n);
+			return -n;
+		}
 	}
+
+	return 0;
 }
 
 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
@@ -504,7 +646,7 @@ void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
 
 void switch_threads(jmp_buf *me, jmp_buf *you)
 {
-	if(UML_SETJMP(me) == 0)
+	if (UML_SETJMP(me) == 0)
 		UML_LONGJMP(you, 1);
 }
 
@@ -519,9 +661,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
 {
 	int n;
 
-	set_handler(SIGWINCH, (__sighandler_t) sig_handler,
-		    SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
-		    SIGVTALRM, -1);
+	set_handler(SIGWINCH);
 
 	/*
 	 * Can't use UML_SETJMP or UML_LONGJMP here because they save
@@ -532,7 +672,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
 	 * after returning to the jumper.
 	 */
 	n = setjmp(initial_jmpbuf);
-	switch(n){
+	switch (n) {
 	case INIT_JMP_NEW_THREAD:
 		(*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
 		(*switch_buf)[0].JB_SP = (unsigned long) stack +
@@ -544,12 +684,14 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
 		break;
 	case INIT_JMP_HALT:
 		kmalloc_ok = 0;
-		return(0);
+		return 0;
 	case INIT_JMP_REBOOT:
 		kmalloc_ok = 0;
-		return(1);
+		return 1;
 	default:
-		panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
+		printk(UM_KERN_ERR "Bad sigsetjmp return in "
+		       "start_idle_thread - %d\n", n);
+		fatal_sigsegv();
 	}
 	longjmp(*switch_buf, 1);
 }
@@ -563,7 +705,7 @@ void initial_thread_cb_skas(void (*proc)(void *), void *arg)
 	cb_back = &here;
 
 	block_signals();
-	if(UML_SETJMP(&here) == 0)
+	if (UML_SETJMP(&here) == 0)
 		UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
 	unblock_signals();
 
@@ -584,17 +726,19 @@ void reboot_skas(void)
 	UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
 }
 
-void switch_mm_skas(struct mm_id *mm_idp)
+void __switch_mm(struct mm_id *mm_idp)
 {
 	int err;
 
-	/* FIXME: need cpu pid in switch_mm_skas */
-	if(proc_mm){
+	/* FIXME: need cpu pid in __switch_mm */
+	if (proc_mm) {
 		err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
 			     mm_idp->u.mm_fd);
-		if(err)
-			panic("switch_mm_skas - PTRACE_SWITCH_MM failed, "
-			      "errno = %d\n", errno);
+		if (err) {
+			printk(UM_KERN_ERR "__switch_mm - PTRACE_SWITCH_MM "
+			       "failed, errno = %d\n", errno);
+			fatal_sigsegv();
+		}
 	}
 	else userspace_pid[0] = mm_idp->u.pid;
 }