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 0000000..ca754fd
--- /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);
+}