signal.c

linux-2.6.15.6

/*
 *  linux/arch/parisc/kernel/signal.c: Architecture-specific signal
 *  handling support.
 *
 *  Copyright (C) 2000 David Huggins-Daines <[e-mail]>
 *  Copyright (C) 2000 Linuxcare, Inc.
 *
 *  Based on the ia64, i386, and alpha versions.
 *
 *  Like the IA-64, we are a recent enough port (we are *starting*
 *  with glibc2.2) that we do not need to support the old non-realtime
 *  Linux signals.  Therefore we don't.  HP/UX signals will go in
 *  arch/parisc/hpux/signal.c when we figure out how to do them.
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.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/stddef.h>
#include <linux/compat.h>
#include <linux/elf.h>
#include <linux/personality.h>
#include <asm/ucontext.h>
#include <asm/rt_sigframe.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/asm-offsets.h>

#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#include "signal32.h"
#endif

#define DEBUG_SIG 0 
#define DEBUG_SIG_LEVEL 2

#if DEBUG_SIG
#define DBG(LEVEL, ...) \
        ((DEBUG_SIG_LEVEL >= LEVEL) \
	? printk(__VA_ARGS__) : (void) 0)
#else
#define DBG(LEVEL, ...)
#endif
	

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

/* gcc will complain if a pointer is cast to an integer of different
 * size.  If you really need to do this (and we do for an ELF32 user
 * application in an ELF64 kernel) then you have to do a cast to an
 * integer of the same size first.  The A() macro accomplishes
 * this. */
#define A(__x)	((unsigned long)(__x))

int do_signal(sigset_t *oldset, struct pt_regs *regs, int in_syscall);

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
#ifdef __LP64__
#include "sys32.h"
#endif

asmlinkage int
sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs)
{
	sigset_t saveset, newset;
#ifdef __LP64__
	compat_sigset_t newset32;

	if(personality(current->personality) == PER_LINUX32){
		/* XXX: Don't preclude handling different sized sigset_t's.  */
		if (sigsetsize != sizeof(compat_sigset_t))
			return -EINVAL;
		if (copy_from_user(&newset32, (compat_sigset_t __user *)unewset, sizeof(newset32)))
			return -EFAULT;
		sigset_32to64(&newset,&newset32);
		
	} else 
#endif
	{
		/* XXX: Don't preclude handling different sized sigset_t's.  */
		if (sigsetsize != sizeof(sigset_t))
			return -EINVAL;
	
		if (copy_from_user(&newset, unewset, sizeof(newset)))
			return -EFAULT;
	}

	sigdelsetmask(&newset, ~_BLOCKABLE);

	spin_lock_irq(&current->sighand->siglock);
	saveset = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	regs->gr[28] = -EINTR;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, regs, 1))
			return -EINTR;
	}
}

/*
 * Do a signal return - restore sigcontext.
 */

/* Trampoline for calling rt_sigreturn() */
#define INSN_LDI_R25_0	 0x34190000 /* ldi  0,%r25 (in_syscall=0) */
#define INSN_LDI_R25_1	 0x34190002 /* ldi  1,%r25 (in_syscall=1) */
#define INSN_LDI_R20	 0x3414015a /* ldi  __NR_rt_sigreturn,%r20 */
#define INSN_BLE_SR2_R0  0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
#define INSN_NOP	 0x08000240 /* nop */
/* For debugging */
#define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */

static long
restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
{
	long err = 0;

	err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
	err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
	err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
	err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
	err |= __get_user(regs->sar, &sc->sc_sar);
	DBG(2,"restore_sigcontext: iaoq is 0x%#lx / 0x%#lx\n", 
			regs->iaoq[0],regs->iaoq[1]);
	DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
	return err;
}

void
sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
{
	struct rt_sigframe __user *frame;
	struct siginfo si;
	sigset_t set;
	unsigned long usp = (regs->gr[30] & ~(0x01UL));
	unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
#ifdef __LP64__
	compat_sigset_t compat_set;
	struct compat_rt_sigframe __user * compat_frame;
	
	if(personality(current->personality) == PER_LINUX32)
		sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
#endif


	/* Unwind the user stack to get the rt_sigframe structure. */
	frame = (struct rt_sigframe __user *)
		(usp - sigframe_size);
	DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);

#ifdef __LP64__
	compat_frame = (struct compat_rt_sigframe __user *)frame;
	
	if(personality(current->personality) == PER_LINUX32){
		DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
		if (__copy_from_user(&compat_set, &compat_frame->uc.uc_sigmask, sizeof(compat_set)))
			goto give_sigsegv;
		sigset_32to64(&set,&compat_set);
	} else
#endif
	{
		if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
			goto give_sigsegv;
	}
		
	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	/* Good thing we saved the old gr[30], eh? */
#ifdef __LP64__
	if(personality(current->personality) == PER_LINUX32){
		DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
				&compat_frame->uc.uc_mcontext);
// FIXME: Load upper half from register file
		if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, 
					&compat_frame->regs, regs))
			goto give_sigsegv;
		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
				usp, &compat_frame->uc.uc_stack);
		if (do_sigaltstack32(&compat_frame->uc.uc_stack, NULL, usp) == -EFAULT)
			goto give_sigsegv;
	} else
#endif
	{
		DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
				&frame->uc.uc_mcontext);
		if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
			goto give_sigsegv;
		DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 
				usp, &frame->uc.uc_stack);
		if (do_sigaltstack(&frame->uc.uc_stack, NULL, usp) == -EFAULT)
			goto give_sigsegv;
	}
		


	/* If we are on the syscall path IAOQ will not be restored, and
	 * if we are on the interrupt path we must not corrupt gr31.
	 */
	if (in_syscall)
		regs->gr[31] = regs->iaoq[0];
#if DEBUG_SIG
	DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
	show_regs(regs);
#endif
	return;

give_sigsegv:
	DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
	si.si_signo = SIGSEGV;
	si.si_errno = 0;
	si.si_code = SI_KERNEL;
	si.si_pid = current->pid;
	si.si_uid = current->uid;
	si.si_addr = &frame->uc;
	force_sig_info(SIGSEGV, &si, current);
	return;
}

/*
 * Set up a signal frame.
 */

static inline void __user *
get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
{
	/*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
	  don't use the parameter it doesn't matter */

	DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
			(unsigned long)ka, sp, frame_size);
	
	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp))
		sp = current->sas_ss_sp; /* Stacks grow up! */

	DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
	return (void __user *) sp; /* Stacks grow up.  Fun. */
}

static long
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
		 
{
	unsigned long flags = 0;
	long err = 0;

	if (on_sig_stack((unsigned long) sc))
		flags |= PARISC_SC_FLAG_ONSTACK;
	if (in_syscall) {
		flags |= PARISC_SC_FLAG_IN_SYSCALL;
		/* regs->iaoq is undefined in the syscall return path */
		err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
		err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
		err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
		err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
			regs->gr[31], regs->gr[31]+4);
	} else {
		err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
		err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
		DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n", 
			regs->iaoq[0], regs->iaoq[1]);
	}

	err |= __put_user(flags, &sc->sc_flags);
	err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
	err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
	err |= __put_user(regs->sar, &sc->sc_sar);
	DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);

	return err;
}

static long
setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
	       sigset_t *set, struct pt_regs *regs, int in_syscall)
{
	struct rt_sigframe __user *frame;
	unsigned long rp, usp;
	unsigned long haddr, sigframe_size;
	int err = 0;
#ifdef __LP64__
	compat_int_t compat_val;
	struct compat_rt_sigframe __user * compat_frame;
	compat_sigset_t compat_set;
#endif
	
	usp = (regs->gr[30] & ~(0x01UL));
	/*FIXME: frame_size parameter is unused, remove it. */
	frame = get_sigframe(ka, usp, sizeof(*frame));

	DBG(1,"SETUP_RT_FRAME: START\n");
	DBG(1,"setup_rt_frame: frame %p info %p\n", frame, info);

	
#ifdef __LP64__

	compat_frame = (struct compat_rt_sigframe __user *)frame;
	
	if(personality(current->personality) == PER_LINUX32) {
		DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
		err |= compat_copy_siginfo_to_user(&compat_frame->info, info);
		DBG(1,"SETUP_RT_FRAME: 1\n");
		compat_val = (compat_int_t)current->sas_ss_sp;
		err |= __put_user(compat_val, &compat_frame->uc.uc_stack.ss_sp);
		DBG(1,"SETUP_RT_FRAME: 2\n");
		compat_val = (compat_int_t)current->sas_ss_size;
		err |= __put_user(compat_val, &compat_frame->uc.uc_stack.ss_size);
		DBG(1,"SETUP_RT_FRAME: 3\n");
		compat_val = sas_ss_flags(regs->gr[30]);		
		err |= __put_user(compat_val, &compat_frame->uc.uc_stack.ss_flags);		
		DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);