signal.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

/*  $Id: signal.c,v 1.108 2001/01/24 21:05:12 davem Exp $
 *  linux/arch/sparc/kernel/signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 1995 David S. Miller ([e-mail])
 *  Copyright (C) 1996 Miguel de Icaza ([e-mail])
 *  Copyright (C) 1997 Eddie C. Dost   ([e-mail])
 */

#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>

#include <asm/uaccess.h>
#include <asm/bitops.h>
#include <asm/ptrace.h>
#include <asm/svr4.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
		   void *fpqueue, unsigned long *fpqdepth);
extern void fpload(unsigned long *fpregs, unsigned long *fsr);

asmlinkage int do_signal(sigset_t *oldset, struct pt_regs * regs,
			 unsigned long orig_o0, int ret_from_syscall);

/* This turned off for production... */
/* #define DEBUG_SIGNALS 1 */
/* #define DEBUG_SIGNALS_TRACE 1 */
/* #define DEBUG_SIGNALS_MAPS 1 */

/* Signal frames: the original one (compatible with SunOS):
 *
 * Set up a signal frame... Make the stack look the way SunOS
 * expects it to look which is basically:
 *
 * ---------------------------------- <-- %sp at signal time
 * Struct sigcontext
 * Signal address
 * Ptr to sigcontext area above
 * Signal code
 * The signal number itself
 * One register window
 * ---------------------------------- <-- New %sp
 */
struct signal_sframe {
	struct reg_window	sig_window;
	int			sig_num;
	int			sig_code;
	struct sigcontext	*sig_scptr;
	int			sig_address;
	struct sigcontext	sig_context;
	unsigned int		extramask[_NSIG_WORDS - 1];
};

/* 
 * And the new one, intended to be used for Linux applications only
 * (we have enough in there to work with clone).
 * All the interesting bits are in the info field.
 */

struct new_signal_frame {
	struct sparc_stackf	ss;
	__siginfo_t		info;
	__siginfo_fpu_t		*fpu_save;
	unsigned long		insns [2] __attribute__ ((aligned (8)));
	unsigned int		extramask[_NSIG_WORDS - 1];
	unsigned int		extra_size; /* Should be 0 */
	__siginfo_fpu_t		fpu_state;
};

struct rt_signal_frame {
	struct sparc_stackf	ss;
	siginfo_t		info;
	struct pt_regs		regs;
	sigset_t		mask;
	__siginfo_fpu_t		*fpu_save;
	unsigned int		insns [2];
	stack_t			stack;
	unsigned int		extra_size; /* Should be 0 */
	__siginfo_fpu_t		fpu_state;
};

int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
{
	if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
		return -EFAULT;
	if (from->si_code < 0)
		return __copy_to_user(to, from, sizeof(siginfo_t));
	else {
		int err;

		/* If you change siginfo_t structure, please be sure
		   this code is fixed accordingly.
		   It should never copy any pad contained in the structure
		   to avoid security leaks, but must copy the generic
		   3 ints plus the relevant union member.  */
		err = __put_user(from->si_signo, &to->si_signo);
		err |= __put_user(from->si_errno, &to->si_errno);
		err |= __put_user((short)from->si_code, &to->si_code);
		switch (from->si_code >> 16) {
		case __SI_CHLD >> 16:
			err |= __put_user(from->si_utime, &to->si_utime);
			err |= __put_user(from->si_stime, &to->si_stime);
		/* case __SI_RT: This is not generated by the kernel as of now.  */
			err |= __put_user(from->si_status, &to->si_status);
		default:
			err |= __put_user(from->si_uid, &to->si_uid);
			err |= __put_user(from->si_pid, &to->si_pid);
			break;
		}
		return err;
	}
}

/* Align macros */
#define SF_ALIGNEDSZ  (((sizeof(struct signal_sframe) + 7) & (~7)))
#define NF_ALIGNEDSZ  (((sizeof(struct new_signal_frame) + 7) & (~7)))
#define RT_ALIGNEDSZ  (((sizeof(struct rt_signal_frame) + 7) & (~7)))

/*
 * atomically swap in the new signal mask, and wait for a signal.
 * This is really tricky on the Sparc, watch out...
 */
asmlinkage void _sigpause_common(old_sigset_t set, struct pt_regs *regs)
{
	sigset_t saveset;

	set &= _BLOCKABLE;
	spin_lock_irq(&current->sigmask_lock);
	saveset = current->blocked;
	siginitset(&current->blocked, set);
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	regs->pc = regs->npc;
	regs->npc += 4;

	/* Condition codes and return value where set here for sigpause,
	 * and so got used by setup_frame, which again causes sigreturn()
	 * to return -EINTR.
	 */
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		/*
		 * Return -EINTR and set condition code here,
		 * so the interrupted system call actually returns
		 * these.
		 */
		regs->psr |= PSR_C;
		regs->u_regs[UREG_I0] = EINTR;
		if (do_signal(&saveset, regs, 0, 0))
			return;
	}
}

asmlinkage void do_sigpause(unsigned int set, struct pt_regs *regs)
{
	_sigpause_common(set, regs);
}

asmlinkage void do_sigsuspend (struct pt_regs *regs)
{
	_sigpause_common(regs->u_regs[UREG_I0], regs);
}

asmlinkage void do_rt_sigsuspend(sigset_t *uset, size_t sigsetsize,
				 struct pt_regs *regs)
{
	sigset_t oldset, set;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t)) {
		regs->psr |= PSR_C;
		regs->u_regs[UREG_I0] = EINVAL;
		return;
	}

	if (copy_from_user(&set, uset, sizeof(set))) {
		regs->psr |= PSR_C;
		regs->u_regs[UREG_I0] = EFAULT;
		return;
	}

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	oldset = current->blocked;
	current->blocked = set;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	regs->pc = regs->npc;
	regs->npc += 4;

	/* Condition codes and return value where set here for sigpause,
	 * and so got used by setup_frame, which again causes sigreturn()
	 * to return -EINTR.
	 */
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		/*
		 * Return -EINTR and set condition code here,
		 * so the interrupted system call actually returns
		 * these.
		 */
		regs->psr |= PSR_C;
		regs->u_regs[UREG_I0] = EINTR;
		if (do_signal(&oldset, regs, 0, 0))
			return;
	}
}

static inline int
restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t *fpu)
{
	int err;
#ifdef CONFIG_SMP
	if (current->flags & PF_USEDFPU)
		regs->psr &= ~PSR_EF;
#else
	if (current == last_task_used_math) {
		last_task_used_math = 0;
		regs->psr &= ~PSR_EF;
	}
#endif
	current->used_math = 1;
	current->flags &= ~PF_USEDFPU;
	
	if (verify_area (VERIFY_READ, fpu, sizeof(*fpu)))
		return -EFAULT;

	err = __copy_from_user(&current->thread.float_regs[0], &fpu->si_float_regs[0],
			       (sizeof(unsigned long) * 32));
	err |= __get_user(current->thread.fsr, &fpu->si_fsr);
	err |= __get_user(current->thread.fpqdepth, &fpu->si_fpqdepth);
	if (current->thread.fpqdepth != 0)
		err |= __copy_from_user(&current->thread.fpqueue[0],
					&fpu->si_fpqueue[0],
					((sizeof(unsigned long) +
					(sizeof(unsigned long *)))*16));
	return err;
}

static inline void do_new_sigreturn (struct pt_regs *regs)
{
	struct new_signal_frame *sf;
	unsigned long up_psr, pc, npc;
	sigset_t set;
	__siginfo_fpu_t *fpu_save;
	int err;

	sf = (struct new_signal_frame *) regs->u_regs [UREG_FP];

	/* 1. Make sure we are not getting garbage from the user */
	if (verify_area (VERIFY_READ, sf, sizeof (*sf)))
		goto segv_and_exit;

	if (((uint) sf) & 3)
		goto segv_and_exit;

	err = __get_user(pc,  &sf->info.si_regs.pc);
	err |= __get_user(npc, &sf->info.si_regs.npc);

	if ((pc | npc) & 3)
		goto segv_and_exit;

	/* 2. Restore the state */
	up_psr = regs->psr;
	err |= __copy_from_user(regs, &sf->info.si_regs, sizeof (struct pt_regs));

	/* User can only change condition codes and FPU enabling in %psr. */
	regs->psr = (up_psr & ~(PSR_ICC | PSR_EF))
		  | (regs->psr & (PSR_ICC | PSR_EF));

	err |= __get_user(fpu_save, &sf->fpu_save);

	if (fpu_save)
		err |= restore_fpu_state(regs, fpu_save);

	/* This is pretty much atomic, no amount locking would prevent
	 * the races which exist anyways.
	 */
	err |= __get_user(set.sig[0], &sf->info.si_mask);
	err |= __copy_from_user(&set.sig[1], &sf->extramask,
			        (_NSIG_WORDS-1) * sizeof(unsigned int));
			   
	if (err)
		goto segv_and_exit;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	current->blocked = set;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);
	return;

segv_and_exit:
	do_exit(SIGSEGV);
}

asmlinkage void do_sigreturn(struct pt_regs *regs)
{
	struct sigcontext *scptr;
	unsigned long pc, npc, psr;
	sigset_t set;
	int err;

	synchronize_user_stack();

	if (current->thread.new_signal)
		return do_new_sigreturn (regs);

	scptr = (struct sigcontext *) regs->u_regs[UREG_I0];

	/* Check sanity of the user arg. */
	if(verify_area(VERIFY_READ, scptr, sizeof(struct sigcontext)) ||
	   (((unsigned long) scptr) & 3))
		goto segv_and_exit;

	err = __get_user(pc, &scptr->sigc_pc);
	err |= __get_user(npc, &scptr->sigc_npc);

	if((pc | npc) & 3)
		goto segv_and_exit;

	/* This is pretty much atomic, no amount locking would prevent
	 * the races which exist anyways.
	 */
	err |= __get_user(set.sig[0], &scptr->sigc_mask);
	/* Note that scptr + 1 points to extramask */
	err |= __copy_from_user(&set.sig[1], scptr + 1,
				(_NSIG_WORDS - 1) * sizeof(unsigned int));
	
	if (err)
		goto segv_and_exit;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	current->blocked = set;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);

	regs->pc = pc;
	regs->npc = npc;

	err = __get_user(regs->u_regs[UREG_FP], &scptr->sigc_sp);
	err |= __get_user(regs->u_regs[UREG_I0], &scptr->sigc_o0);
	err |= __get_user(regs->u_regs[UREG_G1], &scptr->sigc_g1);

	/* User can only change condition codes in %psr. */
	err |= __get_user(psr, &scptr->sigc_psr);
	if (err)
		goto segv_and_exit;
		
	regs->psr &= ~(PSR_ICC);
	regs->psr |= (psr & PSR_ICC);
	return;

segv_and_exit:
	send_sig(SIGSEGV, current, 1);
}

asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_signal_frame *sf;
	unsigned int psr, pc, npc;
	__siginfo_fpu_t *fpu_save;
	sigset_t set;
	stack_t st;
	int err;

	synchronize_user_stack();
	sf = (struct rt_signal_frame *) regs->u_regs[UREG_FP];
	if(verify_area(VERIFY_READ, sf, sizeof(*sf)) ||
	   (((unsigned long) sf) & 0x03))
		goto segv;

	err = __get_user(pc, &sf->regs.pc);
	err |= __get_user(npc, &sf->regs.npc);
	err |= ((pc | npc) & 0x03);

	err |= __get_user(regs->y, &sf->regs.y);
	err |= __get_user(psr, &sf->regs.psr);

	err |= __copy_from_user(&regs->u_regs[UREG_G1], &sf->regs.u_regs[UREG_G1], 15*sizeof(u32));

	regs->psr = (regs->psr & ~PSR_ICC) | (psr & PSR_ICC);

	err |= __get_user(fpu_save, &sf->fpu_save);

	if(fpu_save)
		err |= restore_fpu_state(regs, fpu_save);
	err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
	
	err |= __copy_from_user(&st, &sf->stack, sizeof(stack_t));
	
	if (err)
		goto segv;
		
	regs->pc = pc;
	regs->npc = npc;
	
	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	do_sigaltstack(&st, NULL, (unsigned long)sf);

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sigmask_lock);
	current->blocked = set;
	recalc_sigpending(current);
	spin_unlock_irq(&current->sigmask_lock);
	return;
segv:
	send_sig(SIGSEGV, current, 1);
}

/* Checks if the fp is valid */
static inline int invalid_frame_pointer (void *fp, int fplen)
{
	if ((((unsigned long) fp) & 7) ||
	    !__access_ok((unsigned long)fp, fplen) ||
	    ((sparc_cpu_model == sun4 || sparc_cpu_model == sun4c) &&
	     ((unsigned long) fp < 0xe0000000 && (unsigned long) fp >= 0x20000000)))
		return 1;
	
	return 0;
}

static inline void *get_sigframe(struct sigaction *sa, struct pt_regs *regs, unsigned long framesize)
{
	unsigned long sp;

	sp = regs->u_regs[UREG_FP];