diff options
Diffstat (limited to 'arch/xtensa/kernel/signal.c')
| -rw-r--r-- | arch/xtensa/kernel/signal.c | 713 |
1 files changed, 713 insertions, 0 deletions
diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c new file mode 100644 index 00000000000..df6e1e17b09 --- /dev/null +++ b/arch/xtensa/kernel/signal.c @@ -0,0 +1,713 @@ +// TODO coprocessor stuff +/* + * linux/arch/xtensa/kernel/signal.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson + * + * Joe Taylor <joe@tensilica.com> + * Chris Zankel <chris@zankel.net> + * + * + * + */ + +#include <xtensa/config/core.h> +#include <xtensa/hal.h> +#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/personality.h> +#include <asm/ucontext.h> +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/cacheflush.h> + +#define DEBUG_SIG 0 + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, + struct rusage * ru); +asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset); + +extern struct task_struct *coproc_owners[]; + + +/* + * Atomically swap in the new signal mask, and wait for a signal. + */ + +int sys_sigsuspend(struct pt_regs *regs) +{ + old_sigset_t mask = (old_sigset_t) regs->areg[3]; + 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->areg[2] = -EINTR; + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + if (do_signal(regs, &saveset)) + return -EINTR; + } +} + +asmlinkage int +sys_rt_sigsuspend(struct pt_regs *regs) +{ + sigset_t *unewset = (sigset_t *) regs->areg[4]; + size_t sigsetsize = (size_t) regs->areg[3]; + 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->sighand->siglock); + saveset = current->blocked; + current->blocked = newset; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + regs->areg[2] = -EINTR; + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + if (do_signal(regs, &saveset)) + return -EINTR; + } +} + +asmlinkage 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; +} + +asmlinkage int +sys_sigaltstack(struct pt_regs *regs) +{ + const stack_t *uss = (stack_t *) regs->areg[4]; + stack_t *uoss = (stack_t *) regs->areg[3]; + + if (regs->depc > 64) + panic ("Double exception sys_sigreturn\n"); + + + return do_sigaltstack(uss, uoss, regs->areg[1]); +} + + +/* + * Do a signal return; undo the signal stack. + */ + +struct sigframe +{ + struct sigcontext sc; + struct _cpstate cpstate; + unsigned long extramask[_NSIG_WORDS-1]; + unsigned char retcode[6]; + unsigned int reserved[4]; /* Reserved area for chaining */ + unsigned int window[4]; /* Window of 4 registers for initial context */ +}; + +struct rt_sigframe +{ + struct siginfo info; + struct ucontext uc; + struct _cpstate cpstate; + unsigned char retcode[6]; + unsigned int reserved[4]; /* Reserved area for chaining */ + unsigned int window[4]; /* Window of 4 registers for initial context */ +}; + +extern void release_all_cp (struct task_struct *); + + +// FIXME restore_cpextra +static inline int +restore_cpextra (struct _cpstate *buf) +{ +#if 0 + /* The signal handler may have used coprocessors in which + * case they are still enabled. We disable them to force a + * reloading of the original task's CP state by the lazy + * context-switching mechanisms of CP exception handling. + * Also, we essentially discard any coprocessor state that the + * signal handler created. */ + + struct task_struct *tsk = current; + release_all_cp(tsk); + return __copy_from_user(tsk->thread.cpextra, buf, TOTAL_CPEXTRA_SIZE); +#endif + return 0; +} + +/* Note: We don't copy double exception 'tregs', we have to finish double exc. first before we return to signal handler! This dbl.exc.handler might cause another double exception, but I think we are fine as the situation is the same as if we had returned to the signal handerl and got an interrupt immediately... + */ + + +static int +restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc) +{ + struct thread_struct *thread; + unsigned int err = 0; + unsigned long ps; + struct _cpstate *buf; + +#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) + COPY(pc); + COPY(depc); + COPY(wmask); + COPY(lbeg); + COPY(lend); + COPY(lcount); + COPY(sar); + COPY(windowbase); + COPY(windowstart); +#undef COPY + + /* For PS, restore only PS.CALLINC. + * Assume that all other bits are either the same as for the signal + * handler, or the user mode value doesn't matter (e.g. PS.OWB). + */ + err |= __get_user(ps, &sc->sc_ps); + regs->ps = (regs->ps & ~XCHAL_PS_CALLINC_MASK) + | (ps & XCHAL_PS_CALLINC_MASK); + + /* Additional corruption checks */ + + if ((regs->windowbase >= (XCHAL_NUM_AREGS/4)) + || ((regs->windowstart & ~((1<<(XCHAL_NUM_AREGS/4)) - 1)) != 0) ) + err = 1; + if ((regs->lcount > 0) + && ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) ) + err = 1; + + /* Restore extended register state. + * See struct thread_struct in processor.h. + */ + thread = ¤t->thread; + + err |= __copy_from_user (regs->areg, sc->sc_areg, XCHAL_NUM_AREGS*4); + err |= __get_user(buf, &sc->sc_cpstate); + if (buf) { + if (verify_area(VERIFY_READ, buf, sizeof(*buf))) + goto badframe; + err |= restore_cpextra(buf); + } + + regs->syscall = -1; /* disable syscall checks */ + return err; + +badframe: + return 1; +} + +static inline void +flush_my_cpstate(struct task_struct *tsk) +{ + unsigned long flags; + local_irq_save(flags); + +#if 0 // FIXME + for (i = 0; i < XCHAL_CP_NUM; i++) { + if (tsk == coproc_owners[i]) { + xthal_validate_cp(i); + xthal_save_cpregs(tsk->thread.cpregs_ptr[i], i); + + /* Invalidate and "disown" the cp to allow + * callers the chance to reset cp state in the + * task_struct. */ + + xthal_invalidate_cp(i); + coproc_owners[i] = 0; + } + } +#endif + local_irq_restore(flags); +} + +/* Return codes: + 0: nothing saved + 1: stuff to save, successful + -1: stuff to save, error happened +*/ +static int +save_cpextra (struct _cpstate *buf) +{ +#if (XCHAL_EXTRA_SA_SIZE == 0) && (XCHAL_CP_NUM == 0) + return 0; +#else + + /* FIXME: If a task has never used a coprocessor, there is + * no need to save and restore anything. Tracking this + * information would allow us to optimize this section. + * Perhaps we can use current->used_math or (current->flags & + * PF_USEDFPU) or define a new field in the thread + * structure. */ + + /* We flush any live, task-owned cp state to the task_struct, + * then copy it all to the sigframe. Then we clear all + * cp/extra state in the task_struct, effectively + * clearing/resetting all cp/extra state for the signal + * handler (cp-exception handling will load these new values + * into the cp/extra registers.) This step is important for + * things like a floating-point cp, where the OS must reset + * the FCR to the default rounding mode. */ + + int err = 0; + struct task_struct *tsk = current; + + flush_my_cpstate(tsk); + /* Note that we just copy everything: 'extra' and 'cp' state together.*/ + err |= __copy_to_user(buf, tsk->thread.cp_save, XTENSA_CP_EXTRA_SIZE); + memset(tsk->thread.cp_save, 0, XTENSA_CP_EXTRA_SIZE); + +#if (XTENSA_CP_EXTRA_SIZE == 0) +#error Sanity check on memset above, cpextra_size should not be zero. +#endif + + return err ? -1 : 1; +#endif +} + +static int +setup_sigcontext(struct sigcontext *sc, struct _cpstate *cpstate, + struct pt_regs *regs, unsigned long mask) +{ + struct thread_struct *thread; + int err = 0; + +//printk("setup_sigcontext\n"); +#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) + COPY(pc); + COPY(ps); + COPY(depc); + COPY(wmask); + COPY(lbeg); + COPY(lend); + COPY(lcount); + COPY(sar); + COPY(windowbase); + COPY(windowstart); +#undef COPY + + /* Save extended register state. + * See struct thread_struct in processor.h. + */ + thread = ¤t->thread; + err |= __copy_to_user (sc->sc_areg, regs->areg, XCHAL_NUM_AREGS * 4); + err |= save_cpextra(cpstate); + err |= __put_user(err ? NULL : cpstate, &sc->sc_cpstate); + /* non-iBCS2 extensions.. */ + err |= __put_user(mask, &sc->oldmask); + + return err; +} + +asmlinkage int sys_sigreturn(struct pt_regs *regs) +{ + struct sigframe *frame = (struct sigframe *)regs->areg[1]; + sigset_t set; + if (regs->depc > 64) + panic ("Double exception sys_sigreturn\n"); + + if (verify_area(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; + return regs->areg[2]; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) +{ + struct rt_sigframe *frame = (struct rt_sigframe *)regs->areg[1]; + sigset_t set; + stack_t st; + int ret; + if (regs->depc > 64) + { + printk("!!!!!!! DEPC !!!!!!!\n"); + return 0; + } + + if (verify_area(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; + ret = regs->areg[2]; + + if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) + goto badframe; + /* It is more difficult to avoid calling this function than to + call it and ignore errors. */ + do_sigaltstack(&st, NULL, regs->areg[1]); + + return ret; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* + * Set up a signal frame. + */ + +/* + * Determine which stack to use.. + */ +static inline void * +get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) +{ + if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp)) + sp = current->sas_ss_sp + current->sas_ss_size; + + return (void *)((sp - frame_size) & -16ul); +} + +#define USE_SIGRETURN 0 +#define USE_RT_SIGRETURN 1 + +static int +gen_return_code(unsigned char *codemem, unsigned int use_rt_sigreturn) +{ + unsigned int retcall; + int err = 0; + +#if 0 + /* Ignoring SA_RESTORER for now; it's supposed to be obsolete, + * and the xtensa glibc doesn't use it. + */ + if (ka->sa.sa_flags & SA_RESTORER) { + regs->pr = (unsigned long) ka->sa.sa_restorer; + } else +#endif /* 0 */ + { + +#if (__NR_sigreturn > 255) || (__NR_rt_sigreturn > 255) + +/* The 12-bit immediate is really split up within the 24-bit MOVI + * instruction. As long as the above system call numbers fit within + * 8-bits, the following code works fine. See the Xtensa ISA for + * details. + */ + +#error Generating the MOVI instruction below breaks! +#endif + + retcall = use_rt_sigreturn ? __NR_rt_sigreturn : __NR_sigreturn; + +#ifdef __XTENSA_EB__ /* Big Endian version */ + /* Generate instruction: MOVI a2, retcall */ + err |= __put_user(0x22, &codemem[0]); + err |= __put_user(0x0a, &codemem[1]); + err |= __put_user(retcall, &codemem[2]); + /* Generate instruction: SYSCALL */ + err |= __put_user(0x00, &codemem[3]); + err |= __put_user(0x05, &codemem[4]); + err |= __put_user(0x00, &codemem[5]); + +#elif defined __XTENSA_EL__ /* Little Endian version */ + /* Generate instruction: MOVI a2, retcall */ + err |= __put_user(0x22, &codemem[0]); + err |= __put_user(0xa0, &codemem[1]); + err |= __put_user(retcall, &codemem[2]); + /* Generate instruction: SYSCALL */ + err |= __put_user(0x00, &codemem[3]); + err |= __put_user(0x50, &codemem[4]); + err |= __put_user(0x00, &codemem[5]); +#else +#error Must use compiler for Xtensa processors. +#endif + } + + /* Flush generated code out of the data cache */ + + if (err == 0) + __flush_invalidate_cache_range((unsigned long)codemem, 6UL); + + return err; +} + +static void +set_thread_state(struct pt_regs *regs, void *stack, unsigned char *retaddr, + void *handler, unsigned long arg1, void *arg2, void *arg3) +{ + /* Set up registers for signal handler */ + start_thread(regs, (unsigned long) handler, (unsigned long) stack); + + /* Set up a stack frame for a call4 + * Note: PS.CALLINC is set to one by start_thread + */ + regs->areg[4] = (((unsigned long) retaddr) & 0x3fffffff) | 0x40000000; + regs->areg[6] = arg1; + regs->areg[7] = (unsigned long) arg2; + regs->areg[8] = (unsigned long) arg3; +} + +static void setup_frame(int sig, struct k_sigaction *ka, + sigset_t *set, struct pt_regs *regs) +{ + struct sigframe *frame; + int err = 0; + int signal; + + frame = get_sigframe(ka, regs->areg[1], sizeof(*frame)); + if (regs->depc > 64) + { + printk("!!!!!!! DEPC !!!!!!!\n"); + return; + } + + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + signal = current_thread_info()->exec_domain + && current_thread_info()->exec_domain->signal_invmap + && sig < 32 + ? current_thread_info()->exec_domain->signal_invmap[sig] + : sig; + + err |= setup_sigcontext(&frame->sc, &frame->cpstate, regs, set->sig[0]); + + if (_NSIG_WORDS > 1) { + err |= __copy_to_user(frame->extramask, &set->sig[1], + sizeof(frame->extramask)); + } + + /* Create sys_sigreturn syscall in stack frame */ + err |= gen_return_code(frame->retcode, USE_SIGRETURN); + + if (err) + goto give_sigsegv; + + /* Create signal handler execution context. + * Return context not modified until this point. + */ + set_thread_state(regs, frame, frame->retcode, + ka->sa.sa_handler, signal, &frame->sc, NULL); + + /* Set access mode to USER_DS. Nomenclature is outdated, but + * functionality is used in uaccess.h + */ + set_fs(USER_DS); + + +#if DEBUG_SIG + printk("SIG deliver (%s:%d): signal=%d sp=%p pc=%08x\n", + current->comm, current->pid, signal, frame, regs->pc); +#endif + + 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) +{ + struct rt_sigframe *frame; + int err = 0; + int signal; + + frame = get_sigframe(ka, regs->areg[1], sizeof(*frame)); + if (regs->depc > 64) + panic ("Double exception sys_sigreturn\n"); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + signal = current_thread_info()->exec_domain + && current_thread_info()->exec_domain->signal_invmap + && sig < 32 + ? current_thread_info()->exec_domain->signal_invmap[sig] + : sig; + + err |= copy_siginfo_to_user(&frame->info, info); + + /* Create the ucontext. */ + err |= __put_user(0, &frame->uc.uc_flags); + err |= __put_user(0, &frame->uc.uc_link); + err |= __put_user((void *)current->sas_ss_sp, + &frame->uc.uc_stack.ss_sp); + err |= __put_user(sas_ss_flags(regs->areg[1]), + &frame->uc.uc_stack.ss_flags); + err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); + err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->cpstate, + regs, set->sig[0]); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + + /* Create sys_rt_sigreturn syscall in stack frame */ + err |= gen_return_code(frame->retcode, USE_RT_SIGRETURN); + + if (err) + goto give_sigsegv; + + /* Create signal handler execution context. + * Return context not modified until this point. + */ + set_thread_state(regs, frame, frame->retcode, + ka->sa.sa_handler, signal, &frame->info, &frame->uc); + + /* Set access mode to USER_DS. Nomenclature is outdated, but + * functionality is used in uaccess.h + */ + set_fs(USER_DS); + +#if DEBUG_SIG + printk("SIG rt deliver (%s:%d): signal=%d sp=%p pc=%08x\n", + current->comm, current->pid, signal, frame, regs->pc); +#endif + + return; + +give_sigsegv: + if (sig == SIGSEGV) + ka->sa.sa_handler = SIG_DFL; + force_sig(SIGSEGV, current); +} + + + +/* + * 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. + * + * Note that we go through the signals twice: once to check the signals that + * the kernel can handle, and then we build all the user-level signal handling + * stack-frames in one go after that. + */ +int do_signal(struct pt_regs *regs, sigset_t *oldset) +{ + siginfo_t info; + int signr; + struct k_sigaction ka; + + if (!oldset) + oldset = ¤t->blocked; + + signr = get_signal_to_deliver(&info, &ka, regs, NULL); + + /* Are we from a system call? */ + if (regs->syscall >= 0) { + /* If so, check system call restarting.. */ + switch (regs->areg[2]) { + case ERESTARTNOHAND: + case ERESTART_RESTARTBLOCK: + regs->areg[2] = -EINTR; + break; + + case ERESTARTSYS: + if (!(ka.sa.sa_flags & SA_RESTART)) { + regs->areg[2] = -EINTR; + break; + } + /* fallthrough */ + case ERESTARTNOINTR: + regs->areg[2] = regs->syscall; + regs->pc -= 3; + } + } + + if (signr == 0) + return 0; /* no signals delivered */ + + /* Whee! Actually deliver the signal. */ + + /* Set up the stack frame */ + if (ka.sa.sa_flags & SA_SIGINFO) + setup_rt_frame(signr, &ka, &info, oldset, regs); + else + setup_frame(signr, &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, signr); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + } + return 1; +} |