/*
* linux/arch/ppc/kernel/signal.c
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Derived from "arch/i386/kernel/signal.c"
* Copyright (C) 1991, 1992 Linus Torvalds
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#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/elf.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
#ifndef MIN
#define MIN(a,b) (((a) < (b)) ? (a) : (b))
#endif
#define GP_REGS_SIZE MIN(sizeof(elf_gregset_t), sizeof(struct pt_regs))
extern void syscall_direct_return(struct pt_regs *regs);
int do_signal(sigset_t *oldset, struct pt_regs *regs);
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);
/* First 32bits of unions are always present. */
err |= __put_user(from->si_pid, &to->si_pid);
switch (from->si_code >> 16) {
case __SI_FAULT >> 16:
break;
case __SI_CHLD >> 16:
err |= __put_user(from->si_utime, &to->si_utime);
err |= __put_user(from->si_stime, &to->si_stime);
err |= __put_user(from->si_status, &to->si_status);
default:
err |= __put_user(from->si_uid, &to->si_uid);
break;
/* case __SI_RT: This is not generated by the kernel as of now. */
}
return err;
}
}
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
int
sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int p7,
struct pt_regs *regs)
{
sigset_t saveset;
mask &= _BLOCKABLE;
spin_lock_irq(¤t->sigmask_lock);
saveset = current->blocked;
siginitset(¤t->blocked, mask);
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
regs->result = -EINTR;
regs->gpr[3] = EINTR;
regs->ccr |= 0x10000000;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&saveset, regs))
/*
* If a signal handler needs to be called,
* do_signal() has set R3 to the signal number (the
* first argument of the signal handler), so don't
* overwrite that with EINTR !
* In the other cases, do_signal() doesn't touch
* R3, so it's still set to -EINTR (see above).
*/
return regs->gpr[3];
}
}
int
sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, int p3, int p4, int p6,
int p7, struct pt_regs *regs)
{
sigset_t saveset, newset;
/* 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(¤t->sigmask_lock);
saveset = current->blocked;
current->blocked = newset;
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
regs->result = -EINTR;
regs->gpr[3] = EINTR;
regs->ccr |= 0x10000000;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(&saveset, regs))
return regs->gpr[3];
}
}
int
sys_sigaltstack(const stack_t *uss, stack_t *uoss, int r5, int r6,
int r7, int r8, struct pt_regs *regs)
{
return do_sigaltstack(uss, uoss, regs->gpr[1]);
}
int
sys_sigaction(int sig, const struct old_sigaction *act,
struct old_sigaction *oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
if (act) {
old_sigset_t mask;
if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
__get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
return -EFAULT;
__get_user(new_ka.sa.sa_flags, &act->sa_flags);
__get_user(mask, &act->sa_mask);
siginitset(&new_ka.sa.sa_mask, mask);
}
ret = do_sigaction(sig, (act? &new_ka: NULL), (oact? &old_ka: NULL));
if (!ret && oact) {
if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
return -EFAULT;
__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
}
return ret;
}
/*
* When we have signals to deliver, we set up on the
* user stack, going down from the original stack pointer:
* a sigregs struct
* a sigcontext struct
* a gap of __SIGNAL_FRAMESIZE bytes
*
* Each of these things must be a multiple of 16 bytes in size.
*
*/
struct sigregs {
struct mcontext mctx; /* all the register values */
/* Programs using the rs6000/xcoff abi can save up to 19 gp regs
and 18 fp regs below sp before decrementing it. */
int abigap[56];
};
/* We use the mc_pad field for the signal return trampoline. */
#define tramp mc_pad
/*
* When we have rt signals to deliver, we set up on the
* user stack, going down from the original stack pointer:
* one rt_sigframe struct (siginfo + ucontext + ABI gap)
* a gap of __SIGNAL_FRAMESIZE+16 bytes
* (the +16 is to get the siginfo and ucontext in the same
* positions as in older kernels).
*
* Each of these things must be a multiple of 16 bytes in size.
*
*/
struct rt_sigframe
{
struct siginfo info;
struct ucontext uc;
/* Programs using the rs6000/xcoff abi can save up to 19 gp regs
and 18 fp regs below sp before decrementing it. */
int abigap[56];
};
/*
* Save the current user registers on the user stack.
* We only save the altivec registers if the process has used
* altivec instructions at some point.
*/
static int
save_user_regs(struct pt_regs *regs, struct mcontext *frame, int sigret)
{
/* save general and floating-point registers */
if (regs->msr & MSR_FP)
giveup_fpu(current);
if (__copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE)
|| __copy_to_user(&frame->mc_fregs, current->thread.fpr,
ELF_NFPREG * sizeof(double)))
return 1;
current->thread.fpscr = 0; /* turn off all fp exceptions */
#ifdef CONFIG_ALTIVEC
/* save altivec registers */
if (current->thread.used_vr) {
if (regs->msr & MSR_VEC)
giveup_altivec(current);
if (__copy_to_user(&frame->mc_vregs, current->thread.vr,
ELF_NVRREG * sizeof(vector128)))
return 1;
/* set MSR_VEC in the saved MSR value to indicate that
frame->mc_vregs contains valid data */
if (__put_user(regs->msr | MSR_VEC, &frame->mc_gregs[PT_MSR]))
return 1;
}
/* else assert((regs->msr & MSR_VEC) == 0) */
/* We always copy to/from vrsave, it's 0 if we don't have or don't
* use altivec. Since VSCR only contains 32 bits saved in the least
* significant bits of a vector, we "cheat" and stuff VRSAVE in the
* most significant bits of that same vector. --BenH
*/
if (__put_user(current->thread.vrsave, (u32 *)&frame->mc_vregs[32]))
return 1;
#endif /* CONFIG_ALTIVEC */
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 int
restore_user_regs(struct pt_regs *regs, struct mcontext *sr)
{
#ifdef CONFIG_ALTIVEC
unsigned long msr;
#endif
/* copy up to but not including MSR */
if (__copy_from_user(regs, &sr->mc_gregs, PT_MSR * sizeof(elf_greg_t)))
return 1;
/* copy from orig_r3 (the word after the MSR) up to the end */
if (__copy_from_user(®s->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t)))
return 1;
/* force the process to reload the FP registers from
current->thread when it next does FP instructions */
regs->msr &= ~MSR_FP;
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 (!__get_user(msr, &sr->mc_gregs[PT_MSR]) && (msr & MSR_VEC) != 0) {
/* 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(¤t->thread.vr, 0, ELF_NVRREG * sizeof(vector128));
/* Always get VRSAVE back */
if (__get_user(current->thread.vrsave, (u32 *)&sr->mc_vregs[32]))
return 1;
#endif /* CONFIG_ALTIVEC */
return 0;
}
/*
* Restore the user process's signal mask
*/
static void
restore_sigmask(sigset_t *set)
{
sigdelsetmask(set, ~_BLOCKABLE);
spin_lock_irq(¤t->sigmask_lock);
current->blocked = *set;
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
}
/*
* Set up a signal frame for a "real-time" signal handler
* (one which gets siginfo).
*/
static void
handle_rt_signal(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
unsigned long newsp)
{
struct rt_sigframe *rt_sf;
struct mcontext *frame;
unsigned long origsp = newsp;
/* Set up Signal Frame */
/* Put a Real Time Context onto stack */
newsp -= sizeof(*rt_sf);
rt_sf = (struct rt_sigframe *) newsp;
/* create a stack frame for the caller of the handler */
newsp -= __SIGNAL_FRAMESIZE + 16;
if (verify_area(VERIFY_WRITE, (void *) newsp, origsp - newsp))
goto badframe;
/* Put the siginfo & fill in most of the ucontext */
if (__copy_to_user(&rt_sf->info, info, sizeof(*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(&rt_sf->uc.uc_mcontext, &rt_sf->uc.uc_regs)
|| __copy_to_user(&rt_sf->uc.uc_sigmask, oldset, sizeof(*oldset)))
goto badframe;
/* Save user registers on the stack */
frame = &rt_sf->uc.uc_mcontext;
if (save_user_regs(regs, frame, 0x6666))
goto badframe;
if (put_user(regs->gpr[1], (unsigned long *)newsp))
goto badframe;
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;
regs->link = (unsigned long) frame->tramp;
return;
badframe:
#if DEBUG_SIG
printk("badframe in handle_rt_signal, regs=%p frame=%p newsp=%lx\n",
regs, frame, newsp);
#endif
if (sig == SIGSEGV)
ka->sa.sa_handler = SIG_DFL;
force_sig(SIGSEGV, current);
}
static int do_setcontext(struct ucontext *ucp, struct pt_regs *regs)
{
sigset_t set;
struct mcontext *mcp;
if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(set))
|| __get_user(mcp, &ucp->uc_regs))
return -EFAULT;
restore_sigmask(&set);
if (restore_user_regs(regs, mcp))
return -EFAULT;
return 0;
}
int sys_swapcontext(struct ucontext *old_ctx, struct ucontext *new_ctx,
int r5, int r6, int r7, int r8, struct pt_regs *regs)
{
unsigned char tmp;
if (old_ctx != NULL) {
if (verify_area(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
|| save_user_regs(regs, &old_ctx->uc_mcontext, 0)
|| __copy_to_user(&old_ctx->uc_sigmask,
¤t->blocked, sizeof(sigset_t))
|| __put_user(&old_ctx->uc_mcontext, &old_ctx->uc_regs))
return -EFAULT;
}
if (new_ctx == NULL)
return 0;
if (verify_area(VERIFY_READ, new_ctx, sizeof(*new_ctx))
|| __get_user(tmp, (u8 *) new_ctx)
|| __get_user(tmp, (u8 *) (new_ctx + 1) - 1))
return -EFAULT;
/*
* If we get a fault copying the context into the kernel's
* image of the user's registers, we can't just return -EFAULT
* because the user's registers will be corrupted. For instance
* the NIP value may have been updated but not some of the
* other registers. Given that we have done the verify_area
* and successfully read the first and last bytes of the region
* above, this should only happen in an out-of-memory situation
* or if another thread unmaps the region containing the context.
* We kill the task with a SIGSEGV in this situation.
*/
if (do_setcontext(new_ctx, regs))
do_exit(SIGSEGV);
syscall_direct_return(regs);
/* doesn't actually return back to here */
return 0;
}
int sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe *rt_sf;
stack_t st;
rt_sf = (struct rt_sigframe *)(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
if (verify_area(VERIFY_READ, rt_sf, sizeof(struct rt_sigframe)))
goto bad;
if (do_setcontext(&rt_sf->uc, regs))
goto bad;
/*
* It's not clear whether or why it is desirable to save the
* sigaltstack setting on signal delivery and restore it on
* signal return. But other architectures do this and we have
* always done it up until now so it is probably better not to
* change it. -- paulus
*/
if (__copy_from_user(&st, &rt_sf->uc.uc_stack, sizeof(st)))
goto bad;
do_sigaltstack(&st, NULL, regs->gpr[1]);
return regs->result;
bad:
force_sig(SIGSEGV, current);
return 0;
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(unsigned long sig, struct k_sigaction *ka,
siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
unsigned long newsp)
{
struct sigcontext *sc;
struct sigregs *frame;
unsigned long origsp = newsp;
/* Set up Signal Frame */
newsp -= sizeof(struct sigregs);
frame = (struct sigregs *) newsp;
/* Put a sigcontext on the stack */
newsp -= sizeof(*sc);
sc = (struct sigcontext *) newsp;
/* create a stack frame for the caller of the handler */
newsp -= __SIGNAL_FRAMESIZE;
if (verify_area(VERIFY_WRITE, (void *) newsp, origsp - newsp))
goto badframe;
#if _NSIG != 64
#error "Please adjust handle_signal()"
#endif
if (__put_user((unsigned long) ka->sa.sa_handler, &sc->handler)
|| __put_user(oldset->sig[0], &sc->oldmask)
|| __put_user(oldset->sig[1], &sc->_unused[3])
|| __put_user((struct pt_regs *)frame, &sc->regs)
|| __put_user(sig, &sc->signal))
goto badframe;
if (save_user_regs(regs, &frame->mctx, 0x7777))
goto badframe;
if (put_user(regs->gpr[1], (unsigned long *)newsp))
goto badframe;
regs->gpr[1] = newsp;
regs->gpr[3] = sig;
regs->gpr[4] = (unsigned long) sc;
regs->nip = (unsigned long) ka->sa.sa_handler;
regs->link = (unsigned long) frame->mctx.tramp;
return;
badframe:
#if DEBUG_SIG
printk("badframe in handle_signal, regs=%p frame=%lx newsp=%lx\n",
regs, frame, *newspp);
#endif
if (sig == SIGSEGV)
ka->sa.sa_handler = SIG_DFL;
force_sig(SIGSEGV, current);
}
/*
* Do a signal return; undo the signal stack.
*/
int sys_sigreturn(struct pt_regs *regs)
{
struct sigcontext *sc, sigctx;
struct mcontext *sr;
int ret;
sigset_t set;
sc = (struct sigcontext *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
goto badframe;
set.sig[0] = sigctx.oldmask;
set.sig[1] = sigctx._unused[3];
restore_sigmask(&set);
sr = (struct mcontext *) sigctx.regs;
if (verify_area(VERIFY_READ, sr, sizeof(*sr))
|| restore_user_regs(regs, sr))
goto badframe;
ret = regs->result;
return ret;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static int get_signal_to_deliver(struct siginfo *infop, struct pt_regs *regs)
{
struct k_sigaction *ka;
int signr;
for (;;) {
spin_lock_irq(¤t->sigmask_lock);
signr = dequeue_signal(¤t->blocked, infop);
spin_unlock_irq(¤t->sigmask_lock);
if (!signr)
return 0;
if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
/* Let the debugger run. */
current->exit_code = signr;
current->state = TASK_STOPPED;
notify_parent(current, SIGCHLD);
schedule();
/* We're back. Did the debugger cancel the sig? */
if (!(signr = current->exit_code))
continue;
current->exit_code = 0;
/* The debugger continued. Ignore SIGSTOP. */
if (signr == SIGSTOP)
continue;
/* Update the siginfo structure. Is this good? */
if (signr != infop->si_signo) {
infop->si_signo = signr;
infop->si_errno = 0;
infop->si_code = SI_USER;
infop->si_pid = current->p_pptr->pid;
infop->si_uid = current->p_pptr->uid;
}
/* If the (new) signal is now blocked, requeue it. */
if (sigismember(¤t->blocked, signr)) {
send_sig_info(signr, infop, current);
continue;
}
}
ka = ¤t->sig->action[signr-1];
if (ka->sa.sa_handler == SIG_IGN) {
if (signr != SIGCHLD)
continue;
/* Check for SIGCHLD: it's special. */
while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
/* nothing */;
continue;
}
if (ka->sa.sa_handler == SIG_DFL) {
int exit_code = signr;
/* Init gets no signals it doesn't want. */
if (current->pid == 1)
continue;
switch (signr) {
case SIGCONT: case SIGCHLD: case SIGWINCH: case SIGURG:
continue;
case SIGTSTP: case SIGTTIN: case SIGTTOU:
if (is_orphaned_pgrp(current->pgrp))
continue;
/* FALLTHRU */
case SIGSTOP:
current->state = TASK_STOPPED;
current->exit_code = signr;
if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
notify_parent(current, SIGCHLD);
schedule();
continue;
case SIGQUIT: case SIGILL: case SIGTRAP:
case SIGABRT: case SIGFPE: case SIGSEGV:
case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
if (do_coredump(signr, regs))
exit_code |= 0x80;
/* FALLTHRU */
default:
sig_exit(signr, exit_code, infop);
/* NOTREACHED */
}
}
return signr;
}
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*/
int do_signal(sigset_t *oldset, struct pt_regs *regs)
{
siginfo_t info;
struct k_sigaction *ka;
unsigned long frame, newsp;
int signr;
if (!oldset)
oldset = ¤t->blocked;
newsp = frame = 0;
signr = get_signal_to_deliver(&info, regs);
ka = (signr == 0)? NULL: ¤t->sig->action[signr-1];
if (regs->trap == 0xc00) { /* system call */
switch ((int) regs->result) {
case -ERESTARTSYS:
if (signr == 0 || (ka->sa.sa_flags & SA_RESTART))
goto retry;
/* fall through */
case -ERESTARTNOHAND:
if (signr > 0) {
/* make the system call return an EINTR */
regs->result = -EINTR;
break;
}
/* fall through */
case -ERESTARTNOINTR:
retry:
/* Back up & retry system call */
regs->gpr[3] = regs->orig_gpr3;
regs->nip -= 4;
regs->result = 0;
break;
}
}
if (signr == 0)
return 0; /* no signals delivered */
if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size
&& !on_sig_stack(regs->gpr[1]))
newsp = current->sas_ss_sp + current->sas_ss_size;
else
newsp = regs->gpr[1];
newsp &= ~0xfUL;
/* Whee! Actually deliver the signal. */
if (ka->sa.sa_flags & SA_SIGINFO)
handle_rt_signal(signr, ka, &info, oldset, regs, newsp);
else
handle_signal(signr, ka, &info, oldset, regs, newsp);
if (ka->sa.sa_flags & SA_ONESHOT)
ka->sa.sa_handler = SIG_DFL;
if (!(ka->sa.sa_flags & SA_NODEFER)) {
spin_lock_irq(¤t->sigmask_lock);
sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
sigaddset(¤t->blocked, signr);
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
}
return 1;
}
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