--- /dev/null
+// 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, XTENSA_CP_EXTRA_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;
+
+ spin_lock_irq(¤t->sighand->siglock);
+ sigorsets(¤t->blocked, ¤t->blocked, &ka.sa.sa_mask);
+ if (!(ka.sa.sa_flags & SA_NODEFER))
+ sigaddset(¤t->blocked, signr);
+ recalc_sigpending();
+ spin_unlock_irq(¤t->sighand->siglock);
+ return 1;
+}
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