diff options
Diffstat (limited to 'arch/cris/arch-v32/kernel/signal.c')
| -rw-r--r-- | arch/cris/arch-v32/kernel/signal.c | 708 |
1 files changed, 708 insertions, 0 deletions
diff --git a/arch/cris/arch-v32/kernel/signal.c b/arch/cris/arch-v32/kernel/signal.c new file mode 100644 index 00000000000..fb4c79d5b76 --- /dev/null +++ b/arch/cris/arch-v32/kernel/signal.c @@ -0,0 +1,708 @@ +/* + * Copyright (C) 2003, Axis Communications AB. + */ + +#include <linux/sched.h> +#include <linux/mm.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/syscalls.h> +#include <linux/vmalloc.h> + +#include <asm/io.h> +#include <asm/processor.h> +#include <asm/ucontext.h> +#include <asm/uaccess.h> +#include <asm/arch/ptrace.h> +#include <asm/arch/hwregs/cpu_vect.h> + +extern unsigned long cris_signal_return_page; + +/* Flag to check if a signal is blockable. */ +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +/* + * A syscall in CRIS is really a "break 13" instruction, which is 2 + * bytes. The registers is manipulated so upon return the instruction + * will be executed again. + * + * This relies on that PC points to the instruction after the break call. + */ +#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->erp -= 2; + +/* Signal frames. */ +struct signal_frame { + struct sigcontext sc; + unsigned long extramask[_NSIG_WORDS - 1]; + unsigned char retcode[8]; /* Trampoline code. */ +}; + +struct rt_signal_frame { + struct siginfo *pinfo; + void *puc; + struct siginfo info; + struct ucontext uc; + unsigned char retcode[8]; /* Trampoline code. */ +}; + +int do_signal(int restart, sigset_t *oldset, struct pt_regs *regs); +void keep_debug_flags(unsigned long oldccs, unsigned long oldspc, + struct pt_regs *regs); +/* + * Swap in the new signal mask, and wait for a signal. Define some + * dummy arguments to be able to reach the regs argument. + */ +int +sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof, + long srp, struct pt_regs *regs) +{ + sigset_t saveset; + + mask &= _BLOCKABLE; + + spin_lock_irq(¤t->sighand->siglock); + + saveset = current->blocked; + + siginitset(¤t->blocked, mask); + + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + regs->r10 = -EINTR; + + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + + if (do_signal(0, &saveset, regs)) { + /* + * This point is reached twice: once to call + * the signal handler, then again to return + * from the sigsuspend system call. When + * calling the signal handler, R10 hold the + * signal number as set by do_signal(). The + * sigsuspend call will always return with + * the restored value above; -EINTR. + */ + return regs->r10; + } + } +} + +/* Define some dummy arguments to be able to reach the regs argument. */ +int +sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, long r12, long r13, + long mof, long srp, struct pt_regs *regs) +{ + sigset_t saveset; + sigset_t newset; + + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (copy_from_user(&newset, unewset, sizeof(newset))) + return -EFAULT; + + sigdelsetmask(&newset, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + + saveset = current->blocked; + current->blocked = newset; + + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + regs->r10 = -EINTR; + + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + + if (do_signal(0, &saveset, regs)) { + /* See comment in function above. */ + return regs->r10; + } + } +} + +int +sys_sigaction(int signal, const struct old_sigaction *act, + struct old_sigaction *oact) +{ + int retval; + struct k_sigaction newk; + struct k_sigaction oldk; + + if (act) { + old_sigset_t mask; + + if (!access_ok(VERIFY_READ, act, sizeof(*act)) || + __get_user(newk.sa.sa_handler, &act->sa_handler) || + __get_user(newk.sa.sa_restorer, &act->sa_restorer)) + return -EFAULT; + + __get_user(newk.sa.sa_flags, &act->sa_flags); + __get_user(mask, &act->sa_mask); + siginitset(&newk.sa.sa_mask, mask); + } + + retval = do_sigaction(signal, act ? &newk : NULL, oact ? &oldk : NULL); + + if (!retval && oact) { + if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || + __put_user(oldk.sa.sa_handler, &oact->sa_handler) || + __put_user(oldk.sa.sa_restorer, &oact->sa_restorer)) + return -EFAULT; + + __put_user(oldk.sa.sa_flags, &oact->sa_flags); + __put_user(oldk.sa.sa_mask.sig[0], &oact->sa_mask); + } + + return retval; +} + +int +sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss) +{ + return do_sigaltstack(uss, uoss, rdusp()); +} + +static int +restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) +{ + unsigned int err = 0; + unsigned long old_usp; + + /* Always make any pending restarted system calls return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + + /* + * Restore the registers from &sc->regs. sc is already checked + * for VERIFY_READ since the signal_frame was previously + * checked in sys_sigreturn(). + */ + if (__copy_from_user(regs, sc, sizeof(struct pt_regs))) + goto badframe; + + /* Make that the user-mode flag is set. */ + regs->ccs |= (1 << (U_CCS_BITNR + CCS_SHIFT)); + + /* Restore the old USP. */ + err |= __get_user(old_usp, &sc->usp); + wrusp(old_usp); + + return err; + +badframe: + return 1; +} + +/* Define some dummy arguments to be able to reach the regs argument. */ +asmlinkage int +sys_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp, + struct pt_regs *regs) +{ + sigset_t set; + struct signal_frame __user *frame; + unsigned long oldspc = regs->spc; + unsigned long oldccs = regs->ccs; + + frame = (struct signal_frame *) rdusp(); + + /* + * Since the signal is stacked on a dword boundary, the frame + * should be dword aligned here as well. It it's not, then the + * user is trying some funny business. + */ + if (((long)frame) & 3) + goto badframe; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + + if (__get_user(set.sig[0], &frame->sc.oldmask) || + (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1], + frame->extramask, + sizeof(frame->extramask)))) + goto badframe; + + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + + current->blocked = set; + + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->sc)) + goto badframe; + + keep_debug_flags(oldccs, oldspc, regs); + + return regs->r10; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* Define some dummy variables to be able to reach the regs argument. */ +asmlinkage int +sys_rt_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp, + struct pt_regs *regs) +{ + sigset_t set; + struct rt_signal_frame __user *frame; + unsigned long oldspc = regs->spc; + unsigned long oldccs = regs->ccs; + + frame = (struct rt_signal_frame *) rdusp(); + + /* + * Since the signal is stacked on a dword boundary, the frame + * should be dword aligned here as well. It it's not, then the + * user is trying some funny business. + */ + if (((long)frame) & 3) + goto badframe; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + + current->blocked = set; + + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + if (do_sigaltstack(&frame->uc.uc_stack, NULL, rdusp()) == -EFAULT) + goto badframe; + + keep_debug_flags(oldccs, oldspc, regs); + + return regs->r10; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* Setup a signal frame. */ +static int +setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, + unsigned long mask) +{ + int err; + unsigned long usp; + + err = 0; + usp = rdusp(); + + /* + * Copy the registers. They are located first in sc, so it's + * possible to use sc directly. + */ + err |= __copy_to_user(sc, regs, sizeof(struct pt_regs)); + + err |= __put_user(mask, &sc->oldmask); + err |= __put_user(usp, &sc->usp); + + return err; +} + +/* Figure out where to put the new signal frame - usually on the stack. */ +static inline void __user * +get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) +{ + unsigned long sp; + + sp = rdusp(); + + /* This is the X/Open sanctioned signal stack switching. */ + if (ka->sa.sa_flags & SA_ONSTACK) { + if (!on_sig_stack(sp)) + sp = current->sas_ss_sp + current->sas_ss_size; + } + + /* Make sure the frame is dword-aligned. */ + sp &= ~3; + + return (void __user *)(sp - frame_size); +} + +/* Grab and setup a signal frame. + * + * Basically a lot of state-info is stacked, and arranged for the + * user-mode program to return to the kernel using either a trampiline + * which performs the syscall sigreturn(), or a provided user-mode + * trampoline. + */ +static void +setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, + struct pt_regs * regs) +{ + int err; + unsigned long return_ip; + struct signal_frame __user *frame; + + err = 0; + frame = get_sigframe(ka, regs, sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); + + if (err) + goto give_sigsegv; + + if (_NSIG_WORDS > 1) { + err |= __copy_to_user(frame->extramask, &set->sig[1], + sizeof(frame->extramask)); + } + + if (err) + goto give_sigsegv; + + /* + * Set up to return from user-space. If provided, use a stub + * already located in user-space. + */ + if (ka->sa.sa_flags & SA_RESTORER) { + return_ip = (unsigned long)ka->sa.sa_restorer; + } else { + /* Trampoline - the desired return ip is in the signal return page. */ + return_ip = cris_signal_return_page; + + /* + * This is movu.w __NR_sigreturn, r9; break 13; + * + * WE DO NOT USE IT ANY MORE! It's only left here for historical + * reasons and because gdb uses it as a signature to notice + * signal handler stack frames. + */ + err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0)); + err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2)); + err |= __put_user(0xe93d, (short __user*)(frame->retcode+4)); + } + + if (err) + goto give_sigsegv; + + /* + * Set up registers for signal handler. + * + * Where the code enters now. + * Where the code enter later. + * First argument, signo. + */ + regs->erp = (unsigned long) ka->sa.sa_handler; + regs->srp = return_ip; + regs->r10 = sig; + + /* Actually move the USP to reflect the stacked frame. */ + wrusp((unsigned long)frame); + + return; + +give_sigsegv: + if (sig == SIGSEGV) + ka->sa.sa_handler = SIG_DFL; + + force_sig(SIGSEGV, current); +} + +static void +setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs * regs) +{ + int err; + unsigned long return_ip; + struct rt_signal_frame __user *frame; + + err = 0; + frame = get_sigframe(ka, regs, sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + /* TODO: what is the current->exec_domain stuff and invmap ? */ + + err |= __put_user(&frame->info, &frame->pinfo); + err |= __put_user(&frame->uc, &frame->puc); + err |= copy_siginfo_to_user(&frame->info, info); + + if (err) + goto give_sigsegv; + + /* Clear all the bits of the ucontext we don't use. */ + err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext)); + err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + + if (err) + goto give_sigsegv; + + /* + * Set up to return from user-space. If provided, use a stub + * already located in user-space. + */ + if (ka->sa.sa_flags & SA_RESTORER) { + return_ip = (unsigned long) ka->sa.sa_restorer; + } else { + /* Trampoline - the desired return ip is in the signal return page. */ + return_ip = cris_signal_return_page + 6; + + /* + * This is movu.w __NR_rt_sigreturn, r9; break 13; + * + * WE DO NOT USE IT ANY MORE! It's only left here for historical + * reasons and because gdb uses it as a signature to notice + * signal handler stack frames. + */ + err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0)); + + err |= __put_user(__NR_rt_sigreturn, + (short __user*)(frame->retcode+2)); + + err |= __put_user(0xe93d, (short __user*)(frame->retcode+4)); + } + + if (err) + goto give_sigsegv; + + /* + * Set up registers for signal handler. + * + * Where the code enters now. + * Where the code enters later. + * First argument is signo. + * Second argument is (siginfo_t *). + * Third argument is unused. + */ + regs->erp = (unsigned long) ka->sa.sa_handler; + regs->srp = return_ip; + regs->r10 = sig; + regs->r11 = (unsigned long) &frame->info; + regs->r12 = 0; + + /* Actually move the usp to reflect the stacked frame. */ + wrusp((unsigned long)frame); + + return; + +give_sigsegv: + if (sig == SIGSEGV) + ka->sa.sa_handler = SIG_DFL; + + force_sig(SIGSEGV, current); +} + +/* Invoke a singal handler to, well, handle the signal. */ +extern inline void +handle_signal(int canrestart, unsigned long sig, + siginfo_t *info, struct k_sigaction *ka, + sigset_t *oldset, struct pt_regs * regs) +{ + /* Check if this got called from a system call. */ + if (canrestart) { + /* If so, check system call restarting. */ + switch (regs->r10) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + /* + * This means that the syscall should + * only be restarted if there was no + * handler for the signal, and since + * this point isn't reached unless + * there is a handler, there's no need + * to restart. + */ + regs->r10 = -EINTR; + break; + + case -ERESTARTSYS: + /* + * This means restart the syscall if + * there is no handler, or the handler + * was registered with SA_RESTART. + */ + if (!(ka->sa.sa_flags & SA_RESTART)) { + regs->r10 = -EINTR; + break; + } + + /* Fall through. */ + + case -ERESTARTNOINTR: + /* + * This means that the syscall should + * be called again after the signal + * handler returns. + */ + RESTART_CRIS_SYS(regs); + break; + } + } + + /* Set up the stack frame. */ + if (ka->sa.sa_flags & SA_SIGINFO) + setup_rt_frame(sig, ka, info, oldset, regs); + else + setup_frame(sig, ka, oldset, regs); + + if (ka->sa.sa_flags & SA_ONESHOT) + ka->sa.sa_handler = SIG_DFL; + + if (!(ka->sa.sa_flags & SA_NODEFER)) { + spin_lock_irq(¤t->sighand->siglock); + sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); + sigaddset(¤t->blocked,sig); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + } +} + +/* + * 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. + * + * Also note that the regs structure given here as an argument, is the latest + * pushed pt_regs. It may or may not be the same as the first pushed registers + * when the initial usermode->kernelmode transition took place. Therefore + * we can use user_mode(regs) to see if we came directly from kernel or user + * mode below. + */ +int +do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs) +{ + int signr; + siginfo_t info; + struct k_sigaction ka; + + /* + * The common case should go fast, which is why this point is + * reached from kernel-mode. If that's the case, just return + * without doing anything. + */ + if (!user_mode(regs)) + return 1; + + if (!oldset) + oldset = ¤t->blocked; + + signr = get_signal_to_deliver(&info, &ka, regs, NULL); + + if (signr > 0) { + /* Deliver the signal. */ + handle_signal(canrestart, signr, &info, &ka, oldset, regs); + return 1; + } + + /* Got here from a system call? */ + if (canrestart) { + /* Restart the system call - no handlers present. */ + if (regs->r10 == -ERESTARTNOHAND || + regs->r10 == -ERESTARTSYS || + regs->r10 == -ERESTARTNOINTR) { + RESTART_CRIS_SYS(regs); + } + + if (regs->r10 == -ERESTART_RESTARTBLOCK){ + regs->r10 = __NR_restart_syscall; + regs->erp -= 2; + } + } + + return 0; +} + +asmlinkage void +ugdb_trap_user(struct thread_info *ti, int sig) +{ + if (((user_regs(ti)->exs & 0xff00) >> 8) != SINGLE_STEP_INTR_VECT) { + /* Zero single-step PC if the reason we stopped wasn't a single + step exception. This is to avoid relying on it when it isn't + reliable. */ + user_regs(ti)->spc = 0; + } + /* FIXME: Filter out false h/w breakpoint hits (i.e. EDA + not withing any configured h/w breakpoint range). Synchronize with + what already exists for kernel debugging. */ + if (((user_regs(ti)->exs & 0xff00) >> 8) == BREAK_8_INTR_VECT) { + /* Break 8: subtract 2 from ERP unless in a delay slot. */ + if (!(user_regs(ti)->erp & 0x1)) + user_regs(ti)->erp -= 2; + } + sys_kill(ti->task->pid, sig); +} + +void +keep_debug_flags(unsigned long oldccs, unsigned long oldspc, + struct pt_regs *regs) +{ + if (oldccs & (1 << Q_CCS_BITNR)) { + /* Pending single step due to single-stepping the break 13 + in the signal trampoline: keep the Q flag. */ + regs->ccs |= (1 << Q_CCS_BITNR); + /* S flag should be set - complain if it's not. */ + if (!(oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT)))) { + printk("Q flag but no S flag?"); + } + regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT)); + /* Assume the SPC is valid and interesting. */ + regs->spc = oldspc; + + } else if (oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT))) { + /* If a h/w bp was set in the signal handler we need + to keep the S flag. */ + regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT)); + /* Don't keep the old SPC though; if we got here due to + a single-step, the Q flag should have been set. */ + } else if (regs->spc) { + /* If we were single-stepping *before* the signal was taken, + we don't want to restore that state now, because GDB will + have forgotten all about it. */ + regs->spc = 0; + regs->ccs &= ~(1 << (S_CCS_BITNR + CCS_SHIFT)); + } +} + +/* Set up the trampolines on the signal return page. */ +int __init +cris_init_signal(void) +{ + u16* data = (u16*)kmalloc(PAGE_SIZE, GFP_KERNEL); + + /* This is movu.w __NR_sigreturn, r9; break 13; */ + data[0] = 0x9c5f; + data[1] = __NR_sigreturn; + data[2] = 0xe93d; + /* This is movu.w __NR_rt_sigreturn, r9; break 13; */ + data[3] = 0x9c5f; + data[4] = __NR_rt_sigreturn; + data[5] = 0xe93d; + + /* Map to userspace with appropriate permissions (no write access...) */ + cris_signal_return_page = (unsigned long) + __ioremap_prot(virt_to_phys(data), PAGE_SIZE, PAGE_SIGNAL_TRAMPOLINE); + + return 0; +} + +__initcall(cris_init_signal); |