signal_32.c

linux 内核源代码

		   frame->mc_vregs contains valid data */
		if (__put_user(regs->msr | MSR_SPE, &frame->mc_gregs[PT_MSR]))
			return 1;
	}
	/* else assert((regs->msr & MSR_SPE) == 0) */

	/* We always copy to/from spefscr */
	if (__put_user(current->thread.spefscr, (u32 __user *)&frame->mc_vregs + ELF_NEVRREG))
		return 1;
#endif /* CONFIG_SPE */

	if (sigret) {
		/* Set up the sigreturn trampoline: li r0,sigret; sc */
		if (__put_user(0x38000000UL + sigret, &frame->tramp[0])
		    || __put_user(0x44000002UL, &frame->tramp[1]))
			return 1;
		flush_icache_range((unsigned long) &frame->tramp[0],
				   (unsigned long) &frame->tramp[2]);
	}

	return 0;
}

/*
 * Restore the current user register values from the user stack,
 * (except for MSR).
 */
static long restore_user_regs(struct pt_regs *regs,
			      struct mcontext __user *sr, int sig)
{
	long err;
	unsigned int save_r2 = 0;
	unsigned long msr;

	/*
	 * restore general registers but not including MSR or SOFTE. Also
	 * take care of keeping r2 (TLS) intact if not a signal
	 */
	if (!sig)
		save_r2 = (unsigned int)regs->gpr[2];
	err = restore_general_regs(regs, sr);
	err |= __get_user(msr, &sr->mc_gregs[PT_MSR]);
	if (!sig)
		regs->gpr[2] = (unsigned long) save_r2;
	if (err)
		return 1;

	/* if doing signal return, restore the previous little-endian mode */
	if (sig)
		regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);

	/*
	 * Do this before updating the thread state in
	 * current->thread.fpr/vr/evr.  That way, if we get preempted
	 * and another task grabs the FPU/Altivec/SPE, it won't be
	 * tempted to save the current CPU state into the thread_struct
	 * and corrupt what we are writing there.
	 */
	discard_lazy_cpu_state();

	/* force the process to reload the FP registers from
	   current->thread when it next does FP instructions */
	regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);
	if (__copy_from_user(current->thread.fpr, &sr->mc_fregs,
			     sizeof(sr->mc_fregs)))
		return 1;

#ifdef CONFIG_ALTIVEC
	/* force the process to reload the altivec registers from
	   current->thread when it next does altivec instructions */
	regs->msr &= ~MSR_VEC;
	if (msr & MSR_VEC) {
		/* restore altivec registers from the stack */
		if (__copy_from_user(current->thread.vr, &sr->mc_vregs,
				     sizeof(sr->mc_vregs)))
			return 1;
	} else if (current->thread.used_vr)
		memset(current->thread.vr, 0, ELF_NVRREG * sizeof(vector128));

	/* Always get VRSAVE back */
	if (__get_user(current->thread.vrsave, (u32 __user *)&sr->mc_vregs[32]))
		return 1;
#endif /* CONFIG_ALTIVEC */

#ifdef CONFIG_SPE
	/* force the process to reload the spe registers from
	   current->thread when it next does spe instructions */
	regs->msr &= ~MSR_SPE;
	if (msr & MSR_SPE) {
		/* restore spe registers from the stack */
		if (__copy_from_user(current->thread.evr, &sr->mc_vregs,
				     ELF_NEVRREG * sizeof(u32)))
			return 1;
	} else if (current->thread.used_spe)
		memset(current->thread.evr, 0, ELF_NEVRREG * sizeof(u32));

	/* Always get SPEFSCR back */
	if (__get_user(current->thread.spefscr, (u32 __user *)&sr->mc_vregs + ELF_NEVRREG))
		return 1;
#endif /* CONFIG_SPE */

	return 0;
}

#ifdef CONFIG_PPC64
long compat_sys_rt_sigaction(int sig, const struct sigaction32 __user *act,
		struct sigaction32 __user *oact, size_t sigsetsize)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(compat_sigset_t))
		return -EINVAL;

	if (act) {
		compat_uptr_t handler;

		ret = get_user(handler, &act->sa_handler);
		new_ka.sa.sa_handler = compat_ptr(handler);
		ret |= get_sigset_t(&new_ka.sa.sa_mask, &act->sa_mask);
		ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
		if (ret)
			return -EFAULT;
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
	if (!ret && oact) {
		ret = put_user(to_user_ptr(old_ka.sa.sa_handler), &oact->sa_handler);
		ret |= put_sigset_t(&oact->sa_mask, &old_ka.sa.sa_mask);
		ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
	}
	return ret;
}

/*
 * Note: it is necessary to treat how as an unsigned int, with the
 * corresponding cast to a signed int to insure that the proper
 * conversion (sign extension) between the register representation
 * of a signed int (msr in 32-bit mode) and the register representation
 * of a signed int (msr in 64-bit mode) is performed.
 */
long compat_sys_rt_sigprocmask(u32 how, compat_sigset_t __user *set,
		compat_sigset_t __user *oset, size_t sigsetsize)
{
	sigset_t s;
	sigset_t __user *up;
	int ret;
	mm_segment_t old_fs = get_fs();

	if (set) {
		if (get_sigset_t(&s, set))
			return -EFAULT;
	}

	set_fs(KERNEL_DS);
	/* This is valid because of the set_fs() */
	up = (sigset_t __user *) &s;
	ret = sys_rt_sigprocmask((int)how, set ? up : NULL, oset ? up : NULL,
				 sigsetsize);
	set_fs(old_fs);
	if (ret)
		return ret;
	if (oset) {
		if (put_sigset_t(oset, &s))
			return -EFAULT;
	}
	return 0;
}

long compat_sys_rt_sigpending(compat_sigset_t __user *set, compat_size_t sigsetsize)
{
	sigset_t s;
	int ret;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	/* The __user pointer cast is valid because of the set_fs() */
	ret = sys_rt_sigpending((sigset_t __user *) &s, sigsetsize);
	set_fs(old_fs);
	if (!ret) {
		if (put_sigset_t(set, &s))
			return -EFAULT;
	}
	return ret;
}


int copy_siginfo_to_user32(struct compat_siginfo __user *d, siginfo_t *s)
{
	int err;

	if (!access_ok (VERIFY_WRITE, d, sizeof(*d)))
		return -EFAULT;

	/* 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.
	 * This routine must convert siginfo from 64bit to 32bit as well
	 * at the same time.
	 */
	err = __put_user(s->si_signo, &d->si_signo);
	err |= __put_user(s->si_errno, &d->si_errno);
	err |= __put_user((short)s->si_code, &d->si_code);
	if (s->si_code < 0)
		err |= __copy_to_user(&d->_sifields._pad, &s->_sifields._pad,
				      SI_PAD_SIZE32);
	else switch(s->si_code >> 16) {
	case __SI_CHLD >> 16:
		err |= __put_user(s->si_pid, &d->si_pid);
		err |= __put_user(s->si_uid, &d->si_uid);
		err |= __put_user(s->si_utime, &d->si_utime);
		err |= __put_user(s->si_stime, &d->si_stime);
		err |= __put_user(s->si_status, &d->si_status);
		break;
	case __SI_FAULT >> 16:
		err |= __put_user((unsigned int)(unsigned long)s->si_addr,
				  &d->si_addr);
		break;
	case __SI_POLL >> 16:
		err |= __put_user(s->si_band, &d->si_band);
		err |= __put_user(s->si_fd, &d->si_fd);
		break;
	case __SI_TIMER >> 16:
		err |= __put_user(s->si_tid, &d->si_tid);
		err |= __put_user(s->si_overrun, &d->si_overrun);
		err |= __put_user(s->si_int, &d->si_int);
		break;
	case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
	case __SI_MESGQ >> 16:
		err |= __put_user(s->si_int, &d->si_int);
		/* fallthrough */
	case __SI_KILL >> 16:
	default:
		err |= __put_user(s->si_pid, &d->si_pid);
		err |= __put_user(s->si_uid, &d->si_uid);
		break;
	}
	return err;
}

#define copy_siginfo_to_user	copy_siginfo_to_user32

/*
 * Note: it is necessary to treat pid and sig as unsigned ints, with the
 * corresponding cast to a signed int to insure that the proper conversion
 * (sign extension) between the register representation of a signed int
 * (msr in 32-bit mode) and the register representation of a signed int
 * (msr in 64-bit mode) is performed.
 */
long compat_sys_rt_sigqueueinfo(u32 pid, u32 sig, compat_siginfo_t __user *uinfo)
{
	siginfo_t info;
	int ret;
	mm_segment_t old_fs = get_fs();

	if (copy_from_user (&info, uinfo, 3*sizeof(int)) ||
	    copy_from_user (info._sifields._pad, uinfo->_sifields._pad, SI_PAD_SIZE32))
		return -EFAULT;
	set_fs (KERNEL_DS);
	/* The __user pointer cast is valid becasuse of the set_fs() */
	ret = sys_rt_sigqueueinfo((int)pid, (int)sig, (siginfo_t __user *) &info);
	set_fs (old_fs);
	return ret;
}
/*
 *  Start Alternate signal stack support
 *
 *  System Calls
 *       sigaltatck               compat_sys_sigaltstack
 */

int compat_sys_sigaltstack(u32 __new, u32 __old, int r5,
		      int r6, int r7, int r8, struct pt_regs *regs)
{
	stack_32_t __user * newstack = compat_ptr(__new);
	stack_32_t __user * oldstack = compat_ptr(__old);
	stack_t uss, uoss;
	int ret;
	mm_segment_t old_fs;
	unsigned long sp;
	compat_uptr_t ss_sp;

	/*
	 * set sp to the user stack on entry to the system call
	 * the system call router sets R9 to the saved registers
	 */
	sp = regs->gpr[1];

	/* Put new stack info in local 64 bit stack struct */
	if (newstack) {
		if (get_user(ss_sp, &newstack->ss_sp) ||
		    __get_user(uss.ss_flags, &newstack->ss_flags) ||
		    __get_user(uss.ss_size, &newstack->ss_size))
			return -EFAULT;
		uss.ss_sp = compat_ptr(ss_sp);
	}

	old_fs = get_fs();
	set_fs(KERNEL_DS);
	/* The __user pointer casts are valid because of the set_fs() */
	ret = do_sigaltstack(
		newstack ? (stack_t __user *) &uss : NULL,
		oldstack ? (stack_t __user *) &uoss : NULL,
		sp);
	set_fs(old_fs);
	/* Copy the stack information to the user output buffer */
	if (!ret && oldstack  &&
		(put_user(ptr_to_compat(uoss.ss_sp), &oldstack->ss_sp) ||
		 __put_user(uoss.ss_flags, &oldstack->ss_flags) ||
		 __put_user(uoss.ss_size, &oldstack->ss_size)))
		return -EFAULT;
	return ret;
}
#endif /* CONFIG_PPC64 */

/*
 * Set up a signal frame for a "real-time" signal handler
 * (one which gets siginfo).
 */
int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
		siginfo_t *info, sigset_t *oldset,
		struct pt_regs *regs)
{
	struct rt_sigframe __user *rt_sf;
	struct mcontext __user *frame;
	void __user *addr;
	unsigned long newsp = 0;

	/* Set up Signal Frame */
	/* Put a Real Time Context onto stack */
	rt_sf = get_sigframe(ka, regs, sizeof(*rt_sf));
	addr = rt_sf;
	if (unlikely(rt_sf == NULL))
		goto badframe;

	/* Put the siginfo & fill in most of the ucontext */
	if (copy_siginfo_to_user(&rt_sf->info, info)
	    || __put_user(0, &rt_sf->uc.uc_flags)
	    || __put_user(0, &rt_sf->uc.uc_link)
	    || __put_user(current->sas_ss_sp, &rt_sf->uc.uc_stack.ss_sp)
	    || __put_user(sas_ss_flags(regs->gpr[1]),
			  &rt_sf->uc.uc_stack.ss_flags)
	    || __put_user(current->sas_ss_size, &rt_sf->uc.uc_stack.ss_size)
	    || __put_user(to_user_ptr(&rt_sf->uc.uc_mcontext),
		    &rt_sf->uc.uc_regs)
	    || put_sigset_t(&rt_sf->uc.uc_sigmask, oldset))
		goto badframe;

	/* Save user registers on the stack */
	frame = &rt_sf->uc.uc_mcontext;
	addr = frame;
	if (vdso32_rt_sigtramp && current->mm->context.vdso_base) {
		if (save_user_regs(regs, frame, 0))
			goto badframe;
		regs->link = current->mm->context.vdso_base + vdso32_rt_sigtramp;
	} else {
		if (save_user_regs(regs, frame, __NR_rt_sigreturn))
			goto badframe;
		regs->link = (unsigned long) frame->tramp;
	}

	current->thread.fpscr.val = 0;	/* turn off all fp exceptions */

	/* create a stack frame for the caller of the handler */
	newsp = ((unsigned long)rt_sf) - (__SIGNAL_FRAMESIZE + 16);
	addr = (void __user *)regs->gpr[1];
	if (put_user(regs->gpr[1], (u32 __user *)newsp))
		goto badframe;

	/* Fill registers for signal handler */
	regs->gpr[1] = newsp;
	regs->gpr[3] = sig;
	regs->gpr[4] = (unsigned long) &rt_sf->info;
	regs->gpr[5] = (unsigned long) &rt_sf->uc;
	regs->gpr[6] = (unsigned long) rt_sf;
	regs->nip = (unsigned long) ka->sa.sa_handler;