trap.c

linux内核源码

/*
 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#if 0
#include "kern_util.h"
#include "skas.h"
#include "ptrace_user.h"
#include "sysdep/ptrace_user.h"
#endif

#include <errno.h>
#include <signal.h>
#include "sysdep/ptrace.h"
#include "kern_constants.h"
#include "as-layout.h"
#include "os.h"
#include "sigcontext.h"
#include "task.h"

static struct uml_pt_regs ksig_regs[UM_NR_CPUS];

void sig_handler_common_skas(int sig, void *sc_ptr)
{
	struct sigcontext *sc = sc_ptr;
	struct uml_pt_regs *r;
	void (*handler)(int, struct uml_pt_regs *);
	int save_user, save_errno = errno;

	/*
	 * This is done because to allow SIGSEGV to be delivered inside a SEGV
	 * handler.  This can happen in copy_user, and if SEGV is disabled,
	 * the process will die.
	 * XXX Figure out why this is better than SA_NODEFER
	 */
	if (sig == SIGSEGV) {
		change_sig(SIGSEGV, 1);
		/*
		 * For segfaults, we want the data from the
		 * sigcontext.  In this case, we don't want to mangle
		 * the process registers, so use a static set of
		 * registers.  For other signals, the process
		 * registers are OK.
		 */
		r = &ksig_regs[cpu()];
		copy_sc(r, sc_ptr);
	}
	else r = TASK_REGS(get_current());

	save_user = r->is_user;
	r->is_user = 0;
	if ((sig == SIGFPE) || (sig == SIGSEGV) || (sig == SIGBUS) ||
	    (sig == SIGILL) || (sig == SIGTRAP))
		GET_FAULTINFO_FROM_SC(r->faultinfo, sc);

	change_sig(SIGUSR1, 1);

	handler = sig_info[sig];

	/* unblock SIGVTALRM, SIGIO if sig isn't IRQ signal */
	if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGVTALRM))
		unblock_signals();

	handler(sig, r);

	errno = save_errno;
	r->is_user = save_user;
}