1 files changed, 423 insertions, 0 deletions

diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
new file mode 100644
index 000000000000..f76a2692adca
--- /dev/null
+++ b/arch/um/kernel/process.c
@@ -0,0 +1,423 @@
+/* 
+ * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sched.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <setjmp.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <sys/mman.h>
+#include <asm/unistd.h>
+#include <asm/page.h>
+#include "user_util.h"
+#include "kern_util.h"
+#include "user.h"
+#include "process.h"
+#include "signal_kern.h"
+#include "signal_user.h"
+#include "sysdep/ptrace.h"
+#include "sysdep/sigcontext.h"
+#include "irq_user.h"
+#include "ptrace_user.h"
+#include "time_user.h"
+#include "init.h"
+#include "os.h"
+#include "uml-config.h"
+#include "ptrace_user.h"
+#include "choose-mode.h"
+#include "mode.h"
+#ifdef UML_CONFIG_MODE_SKAS
+#include "skas.h"
+#include "skas_ptrace.h"
+#include "registers.h"
+#endif
+
+void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
+{
+        int flags = 0, pages;
+
+        if(sig_stack != NULL){
+                pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
+                set_sigstack(sig_stack, pages * page_size());
+                flags = SA_ONSTACK;
+        }
+        if(usr1_handler) set_handler(SIGUSR1, usr1_handler, flags, -1);
+}
+
+void init_new_thread_signals(int altstack)
+{
+        int flags = altstack ? SA_ONSTACK : 0;
+
+        set_handler(SIGSEGV, (__sighandler_t) sig_handler, flags,
+                    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
+        set_handler(SIGTRAP, (__sighandler_t) sig_handler, flags, 
+                    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
+        set_handler(SIGFPE, (__sighandler_t) sig_handler, flags, 
+                    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
+        set_handler(SIGILL, (__sighandler_t) sig_handler, flags, 
+                    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
+        set_handler(SIGBUS, (__sighandler_t) sig_handler, flags, 
+                    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
+        set_handler(SIGWINCH, (__sighandler_t) sig_handler, flags, 
+                    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
+        set_handler(SIGUSR2, (__sighandler_t) sig_handler, 
+                    flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
+        signal(SIGHUP, SIG_IGN);
+
+        init_irq_signals(altstack);
+}
+
+struct tramp {
+        int (*tramp)(void *);
+        void *tramp_data;
+        unsigned long temp_stack;
+        int flags;
+        int pid;
+};
+
+/* See above for why sigkill is here */
+
+int sigkill = SIGKILL;
+
+int outer_tramp(void *arg)
+{
+        struct tramp *t;
+        int sig = sigkill;
+
+        t = arg;
+        t->pid = clone(t->tramp, (void *) t->temp_stack + page_size()/2,
+                       t->flags, t->tramp_data);
+        if(t->pid > 0) wait_for_stop(t->pid, SIGSTOP, PTRACE_CONT, NULL);
+        kill(os_getpid(), sig);
+        _exit(0);
+}
+
+int start_fork_tramp(void *thread_arg, unsigned long temp_stack, 
+                     int clone_flags, int (*tramp)(void *))
+{
+        struct tramp arg;
+        unsigned long sp;
+        int new_pid, status, err;
+
+        /* The trampoline will run on the temporary stack */
+        sp = stack_sp(temp_stack);
+
+        clone_flags |= CLONE_FILES | SIGCHLD;
+
+        arg.tramp = tramp;
+        arg.tramp_data = thread_arg;
+        arg.temp_stack = temp_stack;
+        arg.flags = clone_flags;
+
+        /* Start the process and wait for it to kill itself */
+        new_pid = clone(outer_tramp, (void *) sp, clone_flags, &arg);
+        if(new_pid < 0)
+                return(new_pid);
+
+        CATCH_EINTR(err = waitpid(new_pid, &status, 0));
+        if(err < 0)
+                panic("Waiting for outer trampoline failed - errno = %d",
+                      errno);
+
+        if(!WIFSIGNALED(status) || (WTERMSIG(status) != SIGKILL))
+                panic("outer trampoline didn't exit with SIGKILL, "
+                      "status = %d", status);
+
+        return(arg.pid);
+}
+
+static int ptrace_child(void *arg)
+{
+        int ret;
+        int pid = os_getpid(), ppid = getppid();
+        int sc_result;
+
+        if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
+                perror("ptrace");
+                os_kill_process(pid, 0);
+        }
+        os_stop_process(pid);
+
+        /*This syscall will be intercepted by the parent. Don't call more than
+         * once, please.*/
+        sc_result = os_getpid();
+
+        if (sc_result == pid)
+                ret = 1; /*Nothing modified by the parent, we are running
+                           normally.*/
+        else if (sc_result == ppid)
+                ret = 0; /*Expected in check_ptrace and check_sysemu when they
+                           succeed in modifying the stack frame*/
+        else
+                ret = 2; /*Serious trouble! This could be caused by a bug in
+                           host 2.6 SKAS3/2.6 patch before release -V6, together
+                           with a bug in the UML code itself.*/
+        _exit(ret);
+}
+
+static int start_ptraced_child(void **stack_out)
+{
+        void *stack;
+        unsigned long sp;
+        int pid, n, status;
+        
+        stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
+                     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+        if(stack == MAP_FAILED)
+                panic("check_ptrace : mmap failed, errno = %d", errno);
+        sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
+        pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
+        if(pid < 0)
+                panic("check_ptrace : clone failed, errno = %d", errno);
+        CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+        if(n < 0)
+                panic("check_ptrace : wait failed, errno = %d", errno);
+        if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
+                panic("check_ptrace : expected SIGSTOP, got status = %d",
+                      status);
+
+        *stack_out = stack;
+        return(pid);
+}
+
+/* When testing for SYSEMU support, if it is one of the broken versions, we must
+ * just avoid using sysemu, not panic, but only if SYSEMU features are broken.
+ * So only for SYSEMU features we test mustpanic, while normal host features
+ * must work anyway!*/
+static int stop_ptraced_child(int pid, void *stack, int exitcode, int mustpanic)
+{
+        int status, n, ret = 0;
+
+        if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
+                panic("check_ptrace : ptrace failed, errno = %d", errno);
+        CATCH_EINTR(n = waitpid(pid, &status, 0));
+        if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
+                int exit_with = WEXITSTATUS(status);
+                if (exit_with == 2)
+                        printk("check_ptrace : child exited with status 2. "
+                               "Serious trouble happening! Try updating your "
+                               "host skas patch!\nDisabling SYSEMU support.");
+                printk("check_ptrace : child exited with exitcode %d, while "
+                      "expecting %d; status 0x%x", exit_with,
+                      exitcode, status);
+                if (mustpanic)
+                        panic("\n");
+                else
+                        printk("\n");
+                ret = -1;
+        }
+
+        if(munmap(stack, PAGE_SIZE) < 0)
+                panic("check_ptrace : munmap failed, errno = %d", errno);
+        return ret;
+}
+
+static int force_sysemu_disabled = 0;
+
+static int __init nosysemu_cmd_param(char *str, int* add)
+{
+        force_sysemu_disabled = 1;
+        return 0;
+}
+
+__uml_setup("nosysemu", nosysemu_cmd_param,
+                "nosysemu\n"
+                "    Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
+                "    SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
+                "    behaviour of ptrace() and helps reducing host context switch rate.\n"
+                "    To make it working, you need a kernel patch for your host, too.\n"
+                "    See http://perso.wanadoo.fr/laurent.vivier/UML/ for further information.\n\n");
+
+static void __init check_sysemu(void)
+{
+        void *stack;
+        int pid, syscall, n, status, count=0;
+
+        printk("Checking syscall emulation patch for ptrace...");
+        sysemu_supported = 0;
+        pid = start_ptraced_child(&stack);
+
+        if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
+                goto fail;
+
+        CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+        if (n < 0)
+                panic("check_sysemu : wait failed, errno = %d", errno);
+        if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
+                panic("check_sysemu : expected SIGTRAP, "
+                      "got status = %d", status);
+
+        n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
+                   os_getpid());
+        if(n < 0)
+                panic("check_sysemu : failed to modify system "
+                      "call return, errno = %d", errno);
+
+        if (stop_ptraced_child(pid, stack, 0, 0) < 0)
+                goto fail_stopped;
+
+        sysemu_supported = 1;
+        printk("OK\n");
+        set_using_sysemu(!force_sysemu_disabled);
+
+        printk("Checking advanced syscall emulation patch for ptrace...");
+        pid = start_ptraced_child(&stack);
+        while(1){
+                count++;
+                if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
+                        goto fail;
+                CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+                if(n < 0)
+                        panic("check_ptrace : wait failed, errno = %d", errno);
+                if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
+                        panic("check_ptrace : expected (SIGTRAP|SYSCALL_TRAP), "
+                              "got status = %d", status);
+
+                syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
+                                 0);
+                if(syscall == __NR_getpid){
+                        if (!count)
+                                panic("check_ptrace : SYSEMU_SINGLESTEP doesn't singlestep");
+                        n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
+                                   os_getpid());
+                        if(n < 0)
+                                panic("check_sysemu : failed to modify system "
+                                      "call return, errno = %d", errno);
+                        break;
+                }
+        }
+        if (stop_ptraced_child(pid, stack, 0, 0) < 0)
+                goto fail_stopped;
+
+        sysemu_supported = 2;
+        printk("OK\n");
+
+        if ( !force_sysemu_disabled )
+                set_using_sysemu(sysemu_supported);
+        return;
+
+fail:
+        stop_ptraced_child(pid, stack, 1, 0);
+fail_stopped:
+        printk("missing\n");
+}
+
+void __init check_ptrace(void)
+{
+        void *stack;
+        int pid, syscall, n, status;
+
+        printk("Checking that ptrace can change system call numbers...");
+        pid = start_ptraced_child(&stack);
+
+        if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
+                panic("check_ptrace: PTRACE_SETOPTIONS failed, errno = %d", errno);
+
+        while(1){
+                if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
+                        panic("check_ptrace : ptrace failed, errno = %d", 
+                              errno);
+                CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+                if(n < 0)
+                        panic("check_ptrace : wait failed, errno = %d", errno);
+                if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80))
+                        panic("check_ptrace : expected SIGTRAP + 0x80, "
+                              "got status = %d", status);
+                
+                syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
+                                 0);
+                if(syscall == __NR_getpid){
+                        n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
+                                   __NR_getppid);
+                        if(n < 0)
+                                panic("check_ptrace : failed to modify system "
+                                      "call, errno = %d", errno);
+                        break;
+                }
+        }
+        stop_ptraced_child(pid, stack, 0, 1);
+        printk("OK\n");
+        check_sysemu();
+}
+
+int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
+{
+        sigjmp_buf buf;
+        int n;
+
+        *jmp_ptr = &buf;
+        n = sigsetjmp(buf, 1);
+        if(n != 0)
+                return(n);
+        (*fn)(arg);
+        return(0);
+}
+
+void forward_pending_sigio(int target)
+{
+        sigset_t sigs;
+
+        if(sigpending(&sigs)) 
+                panic("forward_pending_sigio : sigpending failed");
+        if(sigismember(&sigs, SIGIO))
+                kill(target, SIGIO);
+}
+
+#ifdef UML_CONFIG_MODE_SKAS
+static inline int check_skas3_ptrace_support(void)
+{
+        struct ptrace_faultinfo fi;
+        void *stack;
+        int pid, n, ret = 1;
+
+        printf("Checking for the skas3 patch in the host...");
+        pid = start_ptraced_child(&stack);
+
+        n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
+        if (n < 0) {
+                if(errno == EIO)
+                        printf("not found\n");
+                else {
+                        perror("not found");
+                }
+                ret = 0;
+        } else {
+                printf("found\n");
+        }
+
+        init_registers(pid);
+        stop_ptraced_child(pid, stack, 1, 1);
+
+        return(ret);
+}
+
+int can_do_skas(void)
+{
+        int ret = 1;
+
+        printf("Checking for /proc/mm...");
+        if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
+                printf("not found\n");
+                ret = 0;
+                goto out;
+        } else {
+                printf("found\n");
+        }
+
+        ret = check_skas3_ptrace_support();
+out:
+        return ret;
+}
+#else
+int can_do_skas(void)
+{
+        return(0);
+}
+#endif