signal32.c

linux-2.6.15.6

{
	struct rt_signal_frame32 __user *sf;
	unsigned int psr, pc, npc, fpu_save, u_ss_sp;
	mm_segment_t old_fs;
	sigset_t set;
	compat_sigset_t seta;
	stack_t st;
	int err, i;
	
	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	synchronize_user_stack();
	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
	sf = (struct rt_signal_frame32 __user *) regs->u_regs[UREG_FP];

	/* 1. Make sure we are not getting garbage from the user */
	if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) ||
	    (((unsigned long) sf) & 3))
		goto segv;

	get_user(pc, &sf->regs.pc);
	__get_user(npc, &sf->regs.npc);

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

	if (test_thread_flag(TIF_32BIT)) {
		pc &= 0xffffffff;
		npc &= 0xffffffff;
	}
	regs->tpc = pc;
	regs->tnpc = npc;

	/* 2. Restore the state */
	err = __get_user(regs->y, &sf->regs.y);
	err |= __get_user(psr, &sf->regs.psr);
	
	for (i = UREG_G1; i <= UREG_I7; i++)
		err |= __get_user(regs->u_regs[i], &sf->regs.u_regs[i]);
	if ((psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS) {
		err |= __get_user(i, &sf->v8plus.g_upper[0]);
		if (i == SIGINFO_EXTRA_V8PLUS_MAGIC) {
			unsigned long asi;

			for (i = UREG_G1; i <= UREG_I7; i++)
				err |= __get_user(((u32 *)regs->u_regs)[2*i], &sf->v8plus.g_upper[i]);
			err |= __get_user(asi, &sf->v8plus.asi);
			regs->tstate &= ~TSTATE_ASI;
			regs->tstate |= ((asi & 0xffUL) << 24UL);
		}
	}

	/* User can only change condition codes in %tstate. */
	regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
	regs->tstate |= psr_to_tstate_icc(psr);

	err |= __get_user(fpu_save, &sf->fpu_save);
	if (fpu_save)
		err |= restore_fpu_state32(regs, &sf->fpu_state);
	err |= copy_from_user(&seta, &sf->mask, sizeof(compat_sigset_t));
	err |= __get_user(u_ss_sp, &sf->stack.ss_sp);
	st.ss_sp = compat_ptr(u_ss_sp);
	err |= __get_user(st.ss_flags, &sf->stack.ss_flags);
	err |= __get_user(st.ss_size, &sf->stack.ss_size);
	if (err)
		goto segv;
		
	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	old_fs = get_fs();
	set_fs(KERNEL_DS);
	do_sigaltstack((stack_t __user *) &st, NULL, (unsigned long)sf);
	set_fs(old_fs);
	
	switch (_NSIG_WORDS) {
		case 4: set.sig[3] = seta.sig[6] + (((long)seta.sig[7]) << 32);
		case 3: set.sig[2] = seta.sig[4] + (((long)seta.sig[5]) << 32);
		case 2: set.sig[1] = seta.sig[2] + (((long)seta.sig[3]) << 32);
		case 1: set.sig[0] = seta.sig[0] + (((long)seta.sig[1]) << 32);
	}
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	return;
segv:
	force_sig(SIGSEGV, current);
}

/* Checks if the fp is valid */
static int invalid_frame_pointer(void __user *fp, int fplen)
{
	if ((((unsigned long) fp) & 7) || ((unsigned long)fp) > 0x100000000ULL - fplen)
		return 1;
	return 0;
}

static void __user *get_sigframe(struct sigaction *sa, struct pt_regs *regs, unsigned long framesize)
{
	unsigned long sp;
	
	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
	sp = regs->u_regs[UREG_FP];
	
	/* This is the X/Open sanctioned signal stack switching.  */
	if (sa->sa_flags & SA_ONSTACK) {
		if (!on_sig_stack(sp) && !((current->sas_ss_sp + current->sas_ss_size) & 7))
			sp = current->sas_ss_sp + current->sas_ss_size;
	}
	return (void __user *)(sp - framesize);
}

static void
setup_frame32(struct sigaction *sa, struct pt_regs *regs, int signr, sigset_t *oldset, siginfo_t *info)
{
	struct signal_sframe32 __user *sframep;
	struct sigcontext32 __user *sc;
	unsigned int seta[_COMPAT_NSIG_WORDS];
	int err = 0;
	void __user *sig_address;
	int sig_code;
	unsigned long pc = regs->tpc;
	unsigned long npc = regs->tnpc;
	unsigned int psr;

	if (test_thread_flag(TIF_32BIT)) {
		pc &= 0xffffffff;
		npc &= 0xffffffff;
	}

	synchronize_user_stack();
	save_and_clear_fpu();

	sframep = (struct signal_sframe32 __user *)
		get_sigframe(sa, regs, SF_ALIGNEDSZ);
	if (invalid_frame_pointer(sframep, sizeof(*sframep))){
		/* Don't change signal code and address, so that
		 * post mortem debuggers can have a look.
		 */
		do_exit(SIGILL);
	}

	sc = &sframep->sig_context;

	/* We've already made sure frame pointer isn't in kernel space... */
	err = __put_user((sas_ss_flags(regs->u_regs[UREG_FP]) == SS_ONSTACK),
			 &sc->sigc_onstack);
	
	switch (_NSIG_WORDS) {
	case 4: seta[7] = (oldset->sig[3] >> 32);
	        seta[6] = oldset->sig[3];
	case 3: seta[5] = (oldset->sig[2] >> 32);
	        seta[4] = oldset->sig[2];
	case 2: seta[3] = (oldset->sig[1] >> 32);
	        seta[2] = oldset->sig[1];
	case 1: seta[1] = (oldset->sig[0] >> 32);
	        seta[0] = oldset->sig[0];
	}
	err |= __put_user(seta[0], &sc->sigc_mask);
	err |= __copy_to_user(sframep->extramask, seta + 1,
			      (_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));
	err |= __put_user(regs->u_regs[UREG_FP], &sc->sigc_sp);
	err |= __put_user(pc, &sc->sigc_pc);
	err |= __put_user(npc, &sc->sigc_npc);
	psr = tstate_to_psr(regs->tstate);
	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
		psr |= PSR_EF;
	err |= __put_user(psr, &sc->sigc_psr);
	err |= __put_user(regs->u_regs[UREG_G1], &sc->sigc_g1);
	err |= __put_user(regs->u_regs[UREG_I0], &sc->sigc_o0);
	err |= __put_user(get_thread_wsaved(), &sc->sigc_oswins);

	err |= copy_in_user((u32 __user *)sframep,
			    (u32 __user *)(regs->u_regs[UREG_FP]),
			    sizeof(struct reg_window32));
		       
	set_thread_wsaved(0); /* So process is allowed to execute. */
	err |= __put_user(signr, &sframep->sig_num);
	sig_address = NULL;
	sig_code = 0;
	if (SI_FROMKERNEL (info) && (info->si_code & __SI_MASK) == __SI_FAULT) {
		sig_address = info->si_addr;
		switch (signr) {
		case SIGSEGV:
			switch (info->si_code) {
			case SEGV_MAPERR: sig_code = SUBSIG_NOMAPPING; break;
			default: sig_code = SUBSIG_PROTECTION; break;
			}
			break;
		case SIGILL:
			switch (info->si_code) {
			case ILL_ILLOPC: sig_code = SUBSIG_ILLINST; break;
			case ILL_PRVOPC: sig_code = SUBSIG_PRIVINST; break;
			case ILL_ILLTRP: sig_code = SUBSIG_BADTRAP(info->si_trapno); break;
			default: sig_code = SUBSIG_STACK; break;
			}
			break;
		case SIGFPE:
			switch (info->si_code) {
			case FPE_INTDIV: sig_code = SUBSIG_IDIVZERO; break;
			case FPE_INTOVF: sig_code = SUBSIG_FPINTOVFL; break;
			case FPE_FLTDIV: sig_code = SUBSIG_FPDIVZERO; break;
			case FPE_FLTOVF: sig_code = SUBSIG_FPOVFLOW; break;
			case FPE_FLTUND: sig_code = SUBSIG_FPUNFLOW; break;
			case FPE_FLTRES: sig_code = SUBSIG_FPINEXACT; break;
			case FPE_FLTINV: sig_code = SUBSIG_FPOPERROR; break;
			default: sig_code = SUBSIG_FPERROR; break;
			}
			break;
		case SIGBUS:
			switch (info->si_code) {
			case BUS_ADRALN: sig_code = SUBSIG_ALIGNMENT; break;
			case BUS_ADRERR: sig_code = SUBSIG_MISCERROR; break;
			default: sig_code = SUBSIG_BUSTIMEOUT; break;
			}
			break;
		case SIGEMT:
			switch (info->si_code) {
			case EMT_TAGOVF: sig_code = SUBSIG_TAG; break;
			}
			break;
		case SIGSYS:
			if (info->si_code == (__SI_FAULT|0x100)) {
				/* See sys_sunos32.c */
				sig_code = info->si_trapno;
				break;
			}
		default:
			sig_address = NULL;
		}
	}
	err |= __put_user(ptr_to_compat(sig_address), &sframep->sig_address);
	err |= __put_user(sig_code, &sframep->sig_code);
	err |= __put_user(ptr_to_compat(sc), &sframep->sig_scptr);
	if (err)
		goto sigsegv;

	regs->u_regs[UREG_FP] = (unsigned long) sframep;
	regs->tpc = (unsigned long) sa->sa_handler;
	regs->tnpc = (regs->tpc + 4);
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}
	return;

sigsegv:
	force_sigsegv(signr, current);
}


static int save_fpu_state32(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
{
	unsigned long *fpregs = current_thread_info()->fpregs;
	unsigned long fprs;
	int err = 0;
	
	fprs = current_thread_info()->fpsaved[0];
	if (fprs & FPRS_DL)
		err |= copy_to_user(&fpu->si_float_regs[0], fpregs,
				    (sizeof(unsigned int) * 32));
	if (fprs & FPRS_DU)
		err |= copy_to_user(&fpu->si_float_regs[32], fpregs+16,
				    (sizeof(unsigned int) * 32));
	err |= __put_user(current_thread_info()->xfsr[0], &fpu->si_fsr);
	err |= __put_user(current_thread_info()->gsr[0], &fpu->si_gsr);
	err |= __put_user(fprs, &fpu->si_fprs);

	return err;
}

static void new_setup_frame32(struct k_sigaction *ka, struct pt_regs *regs,
			      int signo, sigset_t *oldset)
{
	struct new_signal_frame32 __user *sf;
	int sigframe_size;
	u32 psr;
	int i, err;
	unsigned int seta[_COMPAT_NSIG_WORDS];

	/* 1. Make sure everything is clean */
	synchronize_user_stack();
	save_and_clear_fpu();
	
	sigframe_size = NF_ALIGNEDSZ;
	if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
		sigframe_size -= sizeof(__siginfo_fpu_t);

	sf = (struct new_signal_frame32 __user *)
		get_sigframe(&ka->sa, regs, sigframe_size);
	
	if (invalid_frame_pointer(sf, sigframe_size))
		goto sigill;

	if (get_thread_wsaved() != 0)
		goto sigill;

	/* 2. Save the current process state */
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}
	err  = put_user(regs->tpc, &sf->info.si_regs.pc);
	err |= __put_user(regs->tnpc, &sf->info.si_regs.npc);
	err |= __put_user(regs->y, &sf->info.si_regs.y);
	psr = tstate_to_psr(regs->tstate);
	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
		psr |= PSR_EF;
	err |= __put_user(psr, &sf->info.si_regs.psr);
	for (i = 0; i < 16; i++)
		err |= __put_user(regs->u_regs[i], &sf->info.si_regs.u_regs[i]);
	err |= __put_user(sizeof(siginfo_extra_v8plus_t), &sf->extra_size);
	err |= __put_user(SIGINFO_EXTRA_V8PLUS_MAGIC, &sf->v8plus.g_upper[0]);
	for (i = 1; i < 16; i++)
		err |= __put_user(((u32 *)regs->u_regs)[2*i],
				  &sf->v8plus.g_upper[i]);
	err |= __put_user((regs->tstate & TSTATE_ASI) >> 24UL,
			  &sf->v8plus.asi);

	if (psr & PSR_EF) {
		err |= save_fpu_state32(regs, &sf->fpu_state);
		err |= __put_user((u64)&sf->fpu_state, &sf->fpu_save);
	} else {
		err |= __put_user(0, &sf->fpu_save);
	}

	switch (_NSIG_WORDS) {
	case 4: seta[7] = (oldset->sig[3] >> 32);
	        seta[6] = oldset->sig[3];
	case 3: seta[5] = (oldset->sig[2] >> 32);
	        seta[4] = oldset->sig[2];
	case 2: seta[3] = (oldset->sig[1] >> 32);
	        seta[2] = oldset->sig[1];
	case 1: seta[1] = (oldset->sig[0] >> 32);
	        seta[0] = oldset->sig[0];
	}
	err |= __put_user(seta[0], &sf->info.si_mask);
	err |= __copy_to_user(sf->extramask, seta + 1,
			      (_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));

	err |= copy_in_user((u32 __user *)sf,
			    (u32 __user *)(regs->u_regs[UREG_FP]),
			    sizeof(struct reg_window32));
	
	if (err)
		goto sigsegv;

	/* 3. signal handler back-trampoline and parameters */
	regs->u_regs[UREG_FP] = (unsigned long) sf;
	regs->u_regs[UREG_I0] = signo;
	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
	regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

	/* 4. signal handler */
	regs->tpc = (unsigned long) ka->sa.sa_handler;
	regs->tnpc = (regs->tpc + 4);
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}

	/* 5. return to kernel instructions */
	if (ka->ka_restorer) {
		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
	} else {
		/* Flush instruction space. */
		unsigned long address = ((unsigned long)&(sf->insns[0]));
		pgd_t *pgdp = pgd_offset(current->mm, address);
		pud_t *pudp = pud_offset(pgdp, address);
		pmd_t *pmdp = pmd_offset(pudp, address);
		pte_t *ptep;
		pte_t pte;

		regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
	
		err  = __put_user(0x821020d8, &sf->insns[0]); /*mov __NR_sigreturn, %g1*/
		err |= __put_user(0x91d02010, &sf->insns[1]); /*t 0x10*/
		if (err)
			goto sigsegv;

		preempt_disable();
		ptep = pte_offset_map(pmdp, address);
		pte = *ptep;
		if (pte_present(pte)) {
			unsigned long page = (unsigned long)
				page_address(pte_page(pte));

			wmb();
			__asm__ __volatile__("flush	%0 + %1"
					     : /* no outputs */
					     : "r" (page),
					       "r" (address & (PAGE_SIZE - 1))
					     : "memory");
		}
		pte_unmap(ptep);
		preempt_enable();
	}
	return;

sigill:
	do_exit(SIGILL);
sigsegv:
	force_sigsegv(signo, current);
}

/* Setup a Solaris stack frame */
static void
setup_svr4_frame32(struct sigaction *sa, unsigned long pc, unsigned long npc,
		   struct pt_regs *regs, int signr, sigset_t *oldset)
{
	svr4_signal_frame_t __user *sfp;
	svr4_gregset_t  __user *gr;
	svr4_siginfo_t  __user *si;
	svr4_mcontext_t __user *mc;
	svr4_gwindows_t __user *gw;
	svr4_ucontext_t __user *uc;
	svr4_sigset_t setv;
	unsigned int psr;
	int i, err;

	synchronize_user_stack();
	save_and_clear_fpu();
	
	regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
	sfp = (svr4_signal_frame_t __user *)
		get_sigframe(sa, regs,
			     sizeof(struct reg_window32) + SVR4_SF_ALIGNED);

	if (invalid_frame_pointer(sfp, sizeof(*sfp)))
		do_exit(SIGILL);

	/* Start with a clean frame pointer and fill it */
	err = clear_user(sfp, sizeof(*sfp));

	/* Setup convenience variables */
	si = &sfp->si;
	uc = &sfp->uc;
	gw = &sfp->gw;
	mc = &uc->mcontext;
	gr = &mc->greg;
	
	/* FIXME: where am I supposed to put this?
	 * sc->sigc_onstack = old_status;
	 * anyways, it does not look like it is used for anything at all.
	 */
	setv.sigbits[0] = oldset->sig[0];
	setv.sigbits[1] = (oldset->sig[0] >> 32);
	if (_NSIG_WORDS >= 2) {
		setv.sigbits[2] = oldset->sig[1];
		setv.sigbits[3] = (oldset->sig[1] >> 32);
		err |= __copy_to_user(&uc->sigmask, &setv, sizeof(svr4_sigset_t));
	} else
		err |= __copy_to_user(&uc->sigmask, &setv,
				      2 * sizeof(unsigned int));
	
	/* Store registers */
	if (test_thread_flag(TIF_32BIT)) {
		regs->tpc &= 0xffffffff;
		regs->tnpc &= 0xffffffff;
	}
	err |= __put_user(regs->tpc, &((*gr)[SVR4_PC]));
	err |= __put_user(regs->tnpc, &((*gr)[SVR4_NPC]));
	psr = tstate_to_psr(regs->tstate);
	if (current_thread_info()->fpsaved[0] & FPRS_FEF)
		psr |= PSR_EF;
	err |= __put_user(psr, &((*gr)[SVR4_PSR]));
	err |= __put_user(regs->y, &((*gr)[SVR4_Y]));
	
	/* Copy g[1..7] and o[0..7] registers */
	for (i = 0; i < 7; i++)
		err |= __put_user(regs->u_regs[UREG_G1+i], (&(*gr)[SVR4_G1])+i);
	for (i = 0; i < 8; i++)
		err |= __put_user(regs->u_regs[UREG_I0+i], (&(*gr)[SVR4_O0])+i);

	/* Setup sigaltstack */
	err |= __put_user(current->sas_ss_sp, &uc->stack.sp);
	err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &uc->stack.flags);
	err |= __put_user(current->sas_ss_size, &uc->stack.size);

	/* Save the currently window file: */

	/* 1. Link sfp->uc->gwins to our windows */
	err |= __put_user(ptr_to_compat(gw), &mc->gwin);
	    
	/* 2. Number of windows to restore at setcontext (): */
	err |= __put_user(get_thread_wsaved(), &gw->count);

	/* 3. We just pay attention to the gw->count field on setcontext */
	set_thread_wsaved(0); /* So process is allowed to execute. */