sh: Move in the SH-5 signal trampoline impl.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 629 insertions, 0 deletions

diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
new file mode 100644
index 000000000000..ca754fd42437
--- /dev/null
+++ b/arch/sh/kernel/signal_32.c
@@ -0,0 +1,629 @@
+/*
+ *  linux/arch/sh/kernel/signal.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
+ *
+ *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
+ *
+ */
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.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/tty.h>
+#include <linux/elf.h>
+#include <linux/personality.h>
+#include <linux/binfmts.h>
+#include <linux/freezer.h>
+#include <linux/io.h>
+#include <asm/system.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+asmlinkage int
+sys_sigsuspend(old_sigset_t mask,
+               unsigned long r5, unsigned long r6, unsigned long r7,
+               struct pt_regs __regs)
+{
+        mask &= _BLOCKABLE;
+        spin_lock_irq(&current->sighand->siglock);
+        current->saved_sigmask = current->blocked;
+        siginitset(&current->blocked, mask);
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+
+        current->state = TASK_INTERRUPTIBLE;
+        schedule();
+        set_thread_flag(TIF_RESTORE_SIGMASK);
+        return -ERESTARTNOHAND;
+}
+
+asmlinkage int
+sys_sigaction(int sig, const struct old_sigaction __user *act,
+              struct old_sigaction __user *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,
+                unsigned long r6, unsigned long r7,
+                struct pt_regs __regs)
+{
+        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+
+        return do_sigaltstack(uss, uoss, regs->regs[15]);
+}
+
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+
+#define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */
+#if defined(CONFIG_CPU_SH2)
+#define TRAP_NOARG 0xc320               /* Syscall w/no args (NR in R3) */
+#else
+#define TRAP_NOARG 0xc310               /* Syscall w/no args (NR in R3) */
+#endif
+#define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */
+
+struct sigframe
+{
+        struct sigcontext sc;
+        unsigned long extramask[_NSIG_WORDS-1];
+        u16 retcode[8];
+};
+
+struct rt_sigframe
+{
+        struct siginfo info;
+        struct ucontext uc;
+        u16 retcode[8];
+};
+
+#ifdef CONFIG_SH_FPU
+static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
+{
+        struct task_struct *tsk = current;
+
+        if (!(current_cpu_data.flags & CPU_HAS_FPU))
+                return 0;
+
+        set_used_math();
+        return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],
+                                sizeof(long)*(16*2+2));
+}
+
+static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
+                                      struct pt_regs *regs)
+{
+        struct task_struct *tsk = current;
+
+        if (!(current_cpu_data.flags & CPU_HAS_FPU))
+                return 0;
+
+        if (!used_math()) {
+                __put_user(0, &sc->sc_ownedfp);
+                return 0;
+        }
+
+        __put_user(1, &sc->sc_ownedfp);
+
+        /* This will cause a "finit" to be triggered by the next
+           attempted FPU operation by the 'current' process.
+           */
+        clear_used_math();
+
+        unlazy_fpu(tsk, regs);
+        return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,
+                              sizeof(long)*(16*2+2));
+}
+#endif /* CONFIG_SH_FPU */
+
+static int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
+{
+        unsigned int err = 0;
+
+#define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
+                        COPY(regs[1]);
+        COPY(regs[2]);  COPY(regs[3]);
+        COPY(regs[4]);  COPY(regs[5]);
+        COPY(regs[6]);  COPY(regs[7]);
+        COPY(regs[8]);  COPY(regs[9]);
+        COPY(regs[10]); COPY(regs[11]);
+        COPY(regs[12]); COPY(regs[13]);
+        COPY(regs[14]); COPY(regs[15]);
+        COPY(gbr);      COPY(mach);
+        COPY(macl);     COPY(pr);
+        COPY(sr);       COPY(pc);
+#undef COPY
+
+#ifdef CONFIG_SH_FPU
+        if (current_cpu_data.flags & CPU_HAS_FPU) {
+                int owned_fp;
+                struct task_struct *tsk = current;
+
+                regs->sr |= SR_FD; /* Release FPU */
+                clear_fpu(tsk, regs);
+                clear_used_math();
+                __get_user (owned_fp, &sc->sc_ownedfp);
+                if (owned_fp)
+                        err |= restore_sigcontext_fpu(sc);
+        }
+#endif
+
+        regs->tra = -1;         /* disable syscall checks */
+        err |= __get_user(*r0_p, &sc->sc_regs[0]);
+        return err;
+}
+
+asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
+                             unsigned long r6, unsigned long r7,
+                             struct pt_regs __regs)
+{
+        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+        struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
+        sigset_t set;
+        int r0;
+
+        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(&current->sighand->siglock);
+        current->blocked = set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+
+        if (restore_sigcontext(regs, &frame->sc, &r0))
+                goto badframe;
+        return r0;
+
+badframe:
+        force_sig(SIGSEGV, current);
+        return 0;
+}
+
+asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
+                                unsigned long r6, unsigned long r7,
+                                struct pt_regs __regs)
+{
+        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+        struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
+        sigset_t set;
+        stack_t st;
+        int r0;
+
+        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(&current->sighand->siglock);
+        current->blocked = set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+
+        if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
+                goto badframe;
+
+        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((const stack_t __user *)&st, NULL, (unsigned long)frame);
+
+        return r0;
+
+badframe:
+        force_sig(SIGSEGV, current);
+        return 0;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static int
+setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
+                 unsigned long mask)
+{
+        int err = 0;
+
+#define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)
+        COPY(regs[0]);  COPY(regs[1]);
+        COPY(regs[2]);  COPY(regs[3]);
+        COPY(regs[4]);  COPY(regs[5]);
+        COPY(regs[6]);  COPY(regs[7]);
+        COPY(regs[8]);  COPY(regs[9]);
+        COPY(regs[10]); COPY(regs[11]);
+        COPY(regs[12]); COPY(regs[13]);
+        COPY(regs[14]); COPY(regs[15]);
+        COPY(gbr);      COPY(mach);
+        COPY(macl);     COPY(pr);
+        COPY(sr);       COPY(pc);
+#undef COPY
+
+#ifdef CONFIG_SH_FPU
+        err |= save_sigcontext_fpu(sc, regs);
+#endif
+
+        /* non-iBCS2 extensions.. */
+        err |= __put_user(mask, &sc->oldmask);
+
+        return err;
+}
+
+/*
+ * Determine which stack to use..
+ */
+static inline void __user *
+get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
+{
+        if (ka->sa.sa_flags & SA_ONSTACK) {
+                if (sas_ss_flags(sp) == 0)
+                        sp = current->sas_ss_sp + current->sas_ss_size;
+        }
+
+        return (void __user *)((sp - frame_size) & -8ul);
+}
+
+/* These symbols are defined with the addresses in the vsyscall page.
+   See vsyscall-trapa.S.  */
+extern void __user __kernel_sigreturn;
+extern void __user __kernel_rt_sigreturn;
+
+static int setup_frame(int sig, struct k_sigaction *ka,
+                        sigset_t *set, struct pt_regs *regs)
+{
+        struct sigframe __user *frame;
+        int err = 0;
+        int signal;
+
+        frame = get_sigframe(ka, regs->regs[15], 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.  */
+        if (ka->sa.sa_flags & SA_RESTORER) {
+                regs->pr = (unsigned long) ka->sa.sa_restorer;
+#ifdef CONFIG_VSYSCALL
+        } else if (likely(current->mm->context.vdso)) {
+                regs->pr = VDSO_SYM(&__kernel_sigreturn);
+#endif
+        } else {
+                /* Generate return code (system call to sigreturn) */
+                err |= __put_user(MOVW(7), &frame->retcode[0]);
+                err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[2]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[3]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[4]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[5]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[6]);
+                err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
+                regs->pr = (unsigned long) frame->retcode;
+        }
+
+        if (err)
+                goto give_sigsegv;
+
+        /* Set up registers for signal handler */
+        regs->regs[15] = (unsigned long) frame;
+        regs->regs[4] = signal; /* Arg for signal handler */
+        regs->regs[5] = 0;
+        regs->regs[6] = (unsigned long) &frame->sc;
+        regs->pc = (unsigned long) ka->sa.sa_handler;
+
+        set_fs(USER_DS);
+
+        pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
+                 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
+
+        flush_cache_sigtramp(regs->pr);
+
+        if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
+                flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
+
+        return 0;
+
+give_sigsegv:
+        force_sigsegv(sig, current);
+        return -EFAULT;
+}
+
+static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+                           sigset_t *set, struct pt_regs *regs)
+{
+        struct rt_sigframe __user *frame;
+        int err = 0;
+        int signal;
+
+        frame = get_sigframe(ka, regs->regs[15], 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->regs[15]),
+                          &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.  */
+        if (ka->sa.sa_flags & SA_RESTORER) {
+                regs->pr = (unsigned long) ka->sa.sa_restorer;
+#ifdef CONFIG_VSYSCALL
+        } else if (likely(current->mm->context.vdso)) {
+                regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
+#endif
+        } else {
+                /* Generate return code (system call to rt_sigreturn) */
+                err |= __put_user(MOVW(7), &frame->retcode[0]);
+                err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[2]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[3]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[4]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[5]);
+                err |= __put_user(OR_R0_R0, &frame->retcode[6]);
+                err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
+                regs->pr = (unsigned long) frame->retcode;
+        }
+
+        if (err)
+                goto give_sigsegv;
+
+        /* Set up registers for signal handler */
+        regs->regs[15] = (unsigned long) frame;
+        regs->regs[4] = signal; /* Arg for signal handler */
+        regs->regs[5] = (unsigned long) &frame->info;
+        regs->regs[6] = (unsigned long) &frame->uc;
+        regs->pc = (unsigned long) ka->sa.sa_handler;
+
+        set_fs(USER_DS);
+
+        pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
+                 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
+
+        flush_cache_sigtramp(regs->pr);
+
+        if ((-regs->pr & (L1_CACHE_BYTES-1)) < sizeof(frame->retcode))
+                flush_cache_sigtramp(regs->pr + L1_CACHE_BYTES);
+
+        return 0;
+
+give_sigsegv:
+        force_sigsegv(sig, current);
+        return -EFAULT;
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+
+static int
+handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
+              sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0)
+{
+        int ret;
+
+        /* Are we from a system call? */
+        if (regs->tra >= 0) {
+                /* If so, check system call restarting.. */
+                switch (regs->regs[0]) {
+                        case -ERESTART_RESTARTBLOCK:
+                        case -ERESTARTNOHAND:
+                                regs->regs[0] = -EINTR;
+                                break;
+
+                        case -ERESTARTSYS:
+                                if (!(ka->sa.sa_flags & SA_RESTART)) {
+                                        regs->regs[0] = -EINTR;
+                                        break;
+                                }
+                        /* fallthrough */
+                        case -ERESTARTNOINTR:
+                                regs->regs[0] = save_r0;
+                                regs->pc -= instruction_size(
+                                                ctrl_inw(regs->pc - 4));
+                                break;
+                }
+#ifdef CONFIG_GUSA
+        } else {
+                /* gUSA handling */
+                preempt_disable();
+
+                if (regs->regs[15] >= 0xc0000000) {
+                        int offset = (int)regs->regs[15];
+
+                        /* Reset stack pointer: clear critical region mark */
+                        regs->regs[15] = regs->regs[1];
+                        if (regs->pc < regs->regs[0])
+                                /* Go to rewind point #1 */
+                                regs->pc = regs->regs[0] + offset -
+                                        instruction_size(ctrl_inw(regs->pc-4));
+                }
+
+                preempt_enable_no_resched();
+#endif
+        }
+
+        /* Set up the stack frame */
+        if (ka->sa.sa_flags & SA_SIGINFO)
+                ret = setup_rt_frame(sig, ka, info, oldset, regs);
+        else
+                ret = setup_frame(sig, ka, oldset, regs);
+
+        if (ka->sa.sa_flags & SA_ONESHOT)
+                ka->sa.sa_handler = SIG_DFL;
+
+        if (ret == 0) {
+                spin_lock_irq(&current->sighand->siglock);
+                sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
+                if (!(ka->sa.sa_flags & SA_NODEFER))
+                        sigaddset(&current->blocked,sig);
+                recalc_sigpending();
+                spin_unlock_irq(&current->sighand->siglock);
+        }
+
+        return ret;
+}
+
+/*
+ * 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.
+ */
+static void do_signal(struct pt_regs *regs, unsigned int save_r0)
+{
+        siginfo_t info;
+        int signr;
+        struct k_sigaction ka;
+        sigset_t *oldset;
+
+        /*
+         * 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 (!user_mode(regs))
+                return;
+
+        if (try_to_freeze())
+                goto no_signal;
+
+        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                oldset = &current->saved_sigmask;
+        else
+                oldset = &current->blocked;
+
+        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+        if (signr > 0) {
+                /* Whee!  Actually deliver the signal.  */
+                if (handle_signal(signr, &ka, &info, oldset,
+                                  regs, save_r0) == 0) {
+                        /* a signal was successfully delivered; the saved
+                         * sigmask will have been stored in the signal frame,
+                         * and will be restored by sigreturn, so we can simply
+                         * clear the TIF_RESTORE_SIGMASK flag */
+                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                                clear_thread_flag(TIF_RESTORE_SIGMASK);
+                }
+
+                return;
+        }
+
+ no_signal:
+        /* Did we come from a system call? */
+        if (regs->tra >= 0) {
+                /* Restart the system call - no handlers present */
+                if (regs->regs[0] == -ERESTARTNOHAND ||
+                    regs->regs[0] == -ERESTARTSYS ||
+                    regs->regs[0] == -ERESTARTNOINTR) {
+                        regs->regs[0] = save_r0;
+                        regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
+                } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
+                        regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
+                        regs->regs[3] = __NR_restart_syscall;
+                }
+        }
+
+        /* if there's no signal to deliver, we just put the saved sigmask
+         * back */
+        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+                clear_thread_flag(TIF_RESTORE_SIGMASK);
+                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+        }
+}
+
+asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
+                                 __u32 thread_info_flags)
+{
+        /* deal with pending signal delivery */
+        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+                do_signal(regs, save_r0);
+}