1d7173baf2
This patch implements soft interrupts. Interrupt enabling and disabling no longer map to sigprocmask. Rather, a flag is set indicating whether interrupts may be handled. If a signal comes in and interrupts are marked as OK, then it is handled normally. If interrupts are marked as off, then the signal handler simply returns after noting that a signal needs handling. When interrupts are enabled later on, this pending signals flag is checked, and the IRQ handlers are called at that point. The point of this is to reduce the cost of local_irq_save et al, since they are very much more common than the signals that they are enabling and disabling. Soft interrupts produce a speed-up of ~25% on a kernel build. Subtleties - UML uses sigsetjmp/siglongjmp to switch contexts. sigsetjmp has been wrapped in a save_flags-like macro which remembers the interrupt state at setjmp time, and restores it when it is longjmp-ed back to. The enable_signals function has to loop because the IRQ handler disables interrupts before returning. enable_signals has to return with signals enabled, and signals may come in between the disabling and the return to enable_signals. So, it loops for as long as there are pending signals, ensuring that signals are enabled when it finally returns, and that there are no pending signals that need to be dealt with. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
218 lines
4.9 KiB
C
218 lines
4.9 KiB
C
/*
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* Copyright (C) 2002 Jeff Dike (jdike@addtoit.com)
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* Licensed under the GPL
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*/
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#include <unistd.h>
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#include <stdio.h>
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#include <errno.h>
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#include <signal.h>
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#include <setjmp.h>
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#include <linux/unistd.h>
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#include <sys/mman.h>
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#include <sys/wait.h>
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#include "ptrace_user.h"
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#include "os.h"
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#include "user.h"
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#include "user_util.h"
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#include "process.h"
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#include "irq_user.h"
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#include "kern_util.h"
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#include "longjmp.h"
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#define ARBITRARY_ADDR -1
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#define FAILURE_PID -1
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#define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
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#define COMM_SCANF "%*[^)])"
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unsigned long os_process_pc(int pid)
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{
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char proc_stat[STAT_PATH_LEN], buf[256];
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unsigned long pc;
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int fd, err;
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sprintf(proc_stat, "/proc/%d/stat", pid);
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fd = os_open_file(proc_stat, of_read(OPENFLAGS()), 0);
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if(fd < 0){
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printk("os_process_pc - couldn't open '%s', err = %d\n",
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proc_stat, -fd);
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return(ARBITRARY_ADDR);
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}
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err = os_read_file(fd, buf, sizeof(buf));
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if(err < 0){
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printk("os_process_pc - couldn't read '%s', err = %d\n",
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proc_stat, -err);
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os_close_file(fd);
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return(ARBITRARY_ADDR);
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}
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os_close_file(fd);
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pc = ARBITRARY_ADDR;
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if(sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
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"%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
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"%*d %*d %*d %*d %*d %lu", &pc) != 1){
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printk("os_process_pc - couldn't find pc in '%s'\n", buf);
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}
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return(pc);
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}
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int os_process_parent(int pid)
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{
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char stat[STAT_PATH_LEN];
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char data[256];
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int parent, n, fd;
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if(pid == -1) return(-1);
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snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
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fd = os_open_file(stat, of_read(OPENFLAGS()), 0);
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if(fd < 0){
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printk("Couldn't open '%s', err = %d\n", stat, -fd);
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return(FAILURE_PID);
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}
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n = os_read_file(fd, data, sizeof(data));
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os_close_file(fd);
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if(n < 0){
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printk("Couldn't read '%s', err = %d\n", stat, -n);
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return(FAILURE_PID);
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}
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parent = FAILURE_PID;
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n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
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if(n != 1)
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printk("Failed to scan '%s'\n", data);
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return(parent);
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}
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void os_stop_process(int pid)
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{
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kill(pid, SIGSTOP);
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}
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void os_kill_process(int pid, int reap_child)
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{
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kill(pid, SIGKILL);
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if(reap_child)
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CATCH_EINTR(waitpid(pid, NULL, 0));
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}
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/* Kill off a ptraced child by all means available. kill it normally first,
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* then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
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* which it can't exit directly.
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*/
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void os_kill_ptraced_process(int pid, int reap_child)
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{
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kill(pid, SIGKILL);
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ptrace(PTRACE_KILL, pid);
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ptrace(PTRACE_CONT, pid);
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if(reap_child)
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CATCH_EINTR(waitpid(pid, NULL, 0));
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}
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void os_usr1_process(int pid)
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{
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kill(pid, SIGUSR1);
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}
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/* Don't use the glibc version, which caches the result in TLS. It misses some
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* syscalls, and also breaks with clone(), which does not unshare the TLS.
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*/
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inline _syscall0(pid_t, getpid)
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int os_getpid(void)
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{
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return(getpid());
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}
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int os_getpgrp(void)
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{
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return getpgrp();
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}
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int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
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int r, int w, int x)
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{
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void *loc;
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int prot;
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prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
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(x ? PROT_EXEC : 0);
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loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
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fd, off);
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if(loc == MAP_FAILED)
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return(-errno);
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return(0);
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}
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int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
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{
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int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
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(x ? PROT_EXEC : 0));
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if(mprotect(addr, len, prot) < 0)
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return(-errno);
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return(0);
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}
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int os_unmap_memory(void *addr, int len)
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{
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int err;
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err = munmap(addr, len);
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if(err < 0)
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return(-errno);
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return(0);
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}
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void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
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{
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int flags = 0, pages;
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if(sig_stack != NULL){
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pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
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set_sigstack(sig_stack, pages * page_size());
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flags = SA_ONSTACK;
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}
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if(usr1_handler) set_handler(SIGUSR1, usr1_handler, flags, -1);
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}
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void init_new_thread_signals(int altstack)
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{
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int flags = altstack ? SA_ONSTACK : 0;
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set_handler(SIGSEGV, (__sighandler_t) sig_handler, flags,
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SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
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set_handler(SIGTRAP, (__sighandler_t) sig_handler, flags,
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SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
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set_handler(SIGFPE, (__sighandler_t) sig_handler, flags,
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SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
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set_handler(SIGILL, (__sighandler_t) sig_handler, flags,
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SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
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set_handler(SIGBUS, (__sighandler_t) sig_handler, flags,
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SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
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set_handler(SIGUSR2, (__sighandler_t) sig_handler,
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flags, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
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signal(SIGHUP, SIG_IGN);
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init_irq_signals(altstack);
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}
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int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr)
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{
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sigjmp_buf buf;
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int n, enable;
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*jmp_ptr = &buf;
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n = UML_SIGSETJMP(&buf, enable);
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if(n != 0)
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return(n);
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(*fn)(arg);
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return(0);
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}
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