microblaze_v8: Signal support
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: John Linn <john.linn@xilinx.com>
Acked-by: John Williams <john.williams@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
new file mode 100644
index 0000000..ff347b9
--- /dev/null
+++ b/arch/microblaze/kernel/signal.c
@@ -0,0 +1,538 @@
+/*
+ * Signal handling
+ *
+ * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2008-2009 PetaLogix
+ * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
+ * Copyright (C) 2001 NEC Corporation
+ * Copyright (C) 2001 Miles Bader <miles@gnu.org>
+ * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
+ * Copyright (C) 1991,1992 Linus Torvalds
+ *
+ * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
+ *
+ * This file was was derived from the sh version, arch/sh/kernel/signal.c
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file COPYING in the main directory of this
+ * archive for more details.
+ */
+
+#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 <linux/percpu.h>
+#include <linux/linkage.h>
+#include <asm/entry.h>
+#include <asm/ucontext.h>
+#include <linux/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <linux/signal.h>
+#include <linux/syscalls.h>
+#include <asm/cacheflush.h>
+#include <asm/syscalls.h>
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset, int in_sycall);
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+asmlinkage int
+sys_sigsuspend(old_sigset_t mask, 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->r3 = -EINTR;
+ while (1) {
+ current->state = TASK_INTERRUPTIBLE;
+ schedule();
+ if (do_signal(regs, &saveset, 1))
+ return -EINTR;
+ }
+}
+
+asmlinkage int
+sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize,
+ 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->sighand->siglock);
+ saveset = current->blocked;
+ current->blocked = newset;
+ recalc_sigpending();
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ regs->r3 = -EINTR;
+ while (1) {
+ current->state = TASK_INTERRUPTIBLE;
+ schedule();
+ if (do_signal(regs, &saveset, 1))
+ 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 (!access_ok(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 (!access_ok(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(const stack_t __user *uss, stack_t __user *uoss,
+ struct pt_regs *regs)
+{
+ return do_sigaltstack(uss, uoss, regs->r1);
+}
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+
+struct sigframe {
+ struct sigcontext sc;
+ unsigned long extramask[_NSIG_WORDS-1];
+ unsigned long tramp[2]; /* signal trampoline */
+};
+
+struct rt_sigframe {
+ struct siginfo info;
+ struct ucontext uc;
+ unsigned long tramp[2]; /* signal trampoline */
+};
+
+static int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *rval_p)
+{
+ unsigned int err = 0;
+
+#define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); }
+ COPY(r0);
+ COPY(r1);
+ COPY(r2); COPY(r3); COPY(r4); COPY(r5);
+ COPY(r6); COPY(r7); COPY(r8); COPY(r9);
+ COPY(r10); COPY(r11); COPY(r12); COPY(r13);
+ COPY(r14); COPY(r15); COPY(r16); COPY(r17);
+ COPY(r18); COPY(r19); COPY(r20); COPY(r21);
+ COPY(r22); COPY(r23); COPY(r24); COPY(r25);
+ COPY(r26); COPY(r27); COPY(r28); COPY(r29);
+ COPY(r30); COPY(r31);
+ COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
+#undef COPY
+
+ *rval_p = regs->r3;
+
+ return err;
+}
+
+asmlinkage int sys_sigreturn(struct pt_regs *regs)
+{
+ struct sigframe *frame = (struct sigframe *)regs->r1;
+ sigset_t set;
+ int rval;
+
+ 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, &rval))
+ goto badframe;
+ return rval;
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
+{
+ struct rt_sigframe *frame = (struct rt_sigframe *)regs->r1;
+ sigset_t set;
+ stack_t st;
+ int rval;
+
+ 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, &rval))
+ goto badframe;
+
+ if (__copy_from_user((void *)&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->r1);
+
+ return rval;
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static int
+setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
+ unsigned long mask)
+{
+ int err = 0;
+
+#define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); }
+ COPY(r0);
+ COPY(r1);
+ COPY(r2); COPY(r3); COPY(r4); COPY(r5);
+ COPY(r6); COPY(r7); COPY(r8); COPY(r9);
+ COPY(r10); COPY(r11); COPY(r12); COPY(r13);
+ COPY(r14); COPY(r15); COPY(r16); COPY(r17);
+ COPY(r18); COPY(r19); COPY(r20); COPY(r21);
+ COPY(r22); COPY(r23); COPY(r24); COPY(r25);
+ COPY(r26); COPY(r27); COPY(r28); COPY(r29);
+ COPY(r30); COPY(r31);
+ COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
+#undef COPY
+
+ err |= __put_user(mask, &sc->oldmask);
+
+ return err;
+}
+
+/*
+ * Determine which stack to use..
+ */
+static inline void *
+get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
+{
+ /* Default to using normal stack */
+ unsigned long sp = regs->r1;
+
+ 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) & -8UL);
+}
+
+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, sizeof(*frame));
+
+ 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, regs, set->sig[0]);
+
+ if (_NSIG_WORDS > 1) {
+ err |= __copy_to_user(frame->extramask, &set->sig[1],
+ sizeof(frame->extramask));
+ }
+
+ /* Set up to return from userspace. If provided, use a stub
+ already in userspace. */
+ /* minus 8 is offset to cater for "rtsd r15,8" offset */
+ if (ka->sa.sa_flags & SA_RESTORER) {
+ regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8;
+ } else {
+ /* Note, these encodings are _big endian_! */
+
+ /* addi r12, r0, __NR_sigreturn */
+ err |= __put_user(0x31800000 | __NR_sigreturn ,
+ frame->tramp + 0);
+ /* brki r14, 0x8 */
+ err |= __put_user(0xb9cc0008, frame->tramp + 1);
+
+ /* Return from sighandler will jump to the tramp.
+ Negative 8 offset because return is rtsd r15, 8 */
+ regs->r15 = ((unsigned long)frame->tramp)-8;
+
+ __invalidate_cache_sigtramp((unsigned long)frame->tramp);
+ }
+
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up registers for signal handler */
+ regs->r1 = (unsigned long) frame;
+ /* Signal handler args: */
+ regs->r5 = signal; /* Arg 0: signum */
+ regs->r6 = (unsigned long) &frame->sc; /* arg 1: sigcontext */
+
+ /* Offset of 4 to handle microblaze rtid r14, 0 */
+ regs->pc = (unsigned long)ka->sa.sa_handler;
+
+ set_fs(USER_DS);
+
+#ifdef DEBUG_SIG
+ printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
+ current->comm, current->pid, 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, sizeof(*frame));
+
+ 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->r1),
+ &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,
+ regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ /* Set up to return from userspace. If provided, use a stub
+ already in userspace. */
+ /* minus 8 is offset to cater for "rtsd r15,8" */
+ if (ka->sa.sa_flags & SA_RESTORER) {
+ regs->r15 = ((unsigned long)ka->sa.sa_restorer)-8;
+ } else {
+ /* addi r12, r0, __NR_sigreturn */
+ err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
+ frame->tramp + 0);
+ /* brki r14, 0x8 */
+ err |= __put_user(0xb9cc0008, frame->tramp + 1);
+
+ /* Return from sighandler will jump to the tramp.
+ Negative 8 offset because return is rtsd r15, 8 */
+ regs->r15 = ((unsigned long)frame->tramp)-8;
+
+ __invalidate_cache_sigtramp((unsigned long)frame->tramp);
+ }
+
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up registers for signal handler */
+ regs->r1 = (unsigned long) frame;
+ /* Signal handler args: */
+ regs->r5 = signal; /* arg 0: signum */
+ regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
+ regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
+ /* Offset to handle microblaze rtid r14, 0 */
+ regs->pc = (unsigned long)ka->sa.sa_handler;
+
+ set_fs(USER_DS);
+
+#ifdef DEBUG_SIG
+ printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n",
+ current->comm, current->pid, frame, regs->pc);
+#endif
+
+ return;
+
+give_sigsegv:
+ if (sig == SIGSEGV)
+ ka->sa.sa_handler = SIG_DFL;
+ force_sig(SIGSEGV, current);
+}
+
+/* Handle restarting system calls */
+static inline void
+handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
+{
+ switch (regs->r3) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ if (!has_handler)
+ goto do_restart;
+ regs->r3 = -EINTR;
+ break;
+ case -ERESTARTSYS:
+ if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
+ regs->r3 = -EINTR;
+ break;
+ }
+ /* fallthrough */
+ case -ERESTARTNOINTR:
+do_restart:
+ /* offset of 4 bytes to re-execute trap (brki) instruction */
+ regs->pc -= 4;
+ break;
+ }
+}
+
+/*
+ * 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)
+{
+ /* 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.
+ *
+ * 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, int in_syscall)
+{
+ siginfo_t info;
+ int signr;
+ struct k_sigaction ka;
+#ifdef DEBUG_SIG
+ printk(KERN_INFO "do signal: %p %p %d\n", regs, oldset, in_syscall);
+ printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
+ regs->r12, current_thread_info()->flags);
+#endif
+ /*
+ * We want the common case to go fast, which
+ * is why we may in certain cases get here from
+ * kernel mode. Just return without doing anything
+ * if so.
+ */
+ if (kernel_mode(regs))
+ return 1;
+
+ if (!oldset)
+ oldset = ¤t->blocked;
+
+ signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+ if (signr > 0) {
+ /* Whee! Actually deliver the signal. */
+ if (in_syscall)
+ handle_restart(regs, &ka, 1);
+ handle_signal(signr, &ka, &info, oldset, regs);
+ return 1;
+ }
+
+ if (in_syscall)
+ handle_restart(regs, NULL, 0);
+
+ /* Did we come from a system call? */
+ return 0;
+}