[PATCH 14/16] h8300: signal handler

[Yoshinori Sato <ysato@users.sourceforge.jp>]

Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>

 create mode 100644 arch/h8300/kernel/signal.c

diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
new file mode 100644
index 0000000..d5bf4f7
--- /dev/null
+++ b/arch/h8300/kernel/signal.c
@@ -0,0 +1,330 @@
+/*
+ *  linux/arch/h8300/kernel/signal.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * 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.
+ */
+
+/*
+ * uClinux H8/300 support by Yoshinori Sato <ysato@users.sourceforge.jp>
+ *                and David McCullough <davidm@snapgear.com>
+ *
+ * Based on
+ * Linux/m68k by Hamish Macdonald
+ */
+
+/*
+ * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
+ * Atari :-) Current limitation: Only one sigstack can be active at one time.
+ * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
+ * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
+ * signal handlers!
+ */
+
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/syscalls.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/ptrace.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/highuid.h>
+#include <linux/personality.h>
+#include <linux/tty.h>
+#include <linux/binfmts.h>
+#include <linux/tracehook.h>
+
+#include <asm/setup.h>
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/traps.h>
+#include <asm/ucontext.h>
+
+/*
+ * Do a signal return; undo the signal stack.
+ *
+ * Keep the return code on the stack quadword aligned!
+ * That makes the cache flush below easier.
+ */
+
+struct rt_sigframe {
+	long dummy_er0;
+	long dummy_vector;
+#if defined(CONFIG_CPU_H8S)
+	short dummy_exr;
+#endif
+	long dummy_pc;
+	char *pretcode;
+	struct siginfo *pinfo;
+	void *puc;
+	unsigned char retcode[8];
+	struct siginfo info;
+	struct ucontext uc;
+	int sig;
+} __packed __aligned(2);
+
+static inline int
+restore_sigcontext(struct sigcontext *usc, int *pd0)
+{
+	struct pt_regs *regs = current_pt_regs();
+	int err = 0;
+	unsigned int ccr;
+	unsigned int usp;
+	unsigned int er0;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+#define COPY(r) err |= __get_user(regs->r, &usc->sc_##r)    /* restore passed registers */
+	COPY(er1);
+	COPY(er2);
+	COPY(er3);
+	COPY(er5);
+	COPY(pc);
+	ccr = regs->ccr & 0x10;
+	COPY(ccr);
+#undef COPY
+	regs->ccr &= 0xef;
+	regs->ccr |= ccr;
+	regs->orig_er0 = -1;		/* disable syscall checks */
+	err |= __get_user(usp, &usc->sc_usp);
+	wrusp(usp);
+
+	err |= __get_user(er0, &usc->sc_er0);
+	*pd0 = er0;
+	return err;
+}
+
+asmlinkage int sys_rt_sigreturn(void)
+{
+	unsigned long usp = rdusp();
+	struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
+	sigset_t set;
+	int er0;
+
+	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+		goto badframe;
+
+	set_current_blocked(&set);
+
+	if (restore_sigcontext(&frame->uc.uc_mcontext, &er0))
+		goto badframe;
+
+	if (restore_altstack(&frame->uc.uc_stack))
+		goto badframe;
+
+	return er0;
+
+badframe:
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+
+static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
+			     unsigned long mask)
+{
+	int err = 0;
+
+	err |= __put_user(regs->er0, &sc->sc_er0);
+	err |= __put_user(regs->er1, &sc->sc_er1);
+	err |= __put_user(regs->er2, &sc->sc_er2);
+	err |= __put_user(regs->er3, &sc->sc_er3);
+	err |= __put_user(regs->er4, &sc->sc_er4);
+	err |= __put_user(regs->er5, &sc->sc_er5);
+	err |= __put_user(regs->er6, &sc->sc_er6);
+	err |= __put_user(rdusp(),   &sc->sc_usp);
+	err |= __put_user(regs->pc,  &sc->sc_pc);
+	err |= __put_user(regs->ccr, &sc->sc_ccr);
+	err |= __put_user(mask,      &sc->sc_mask);
+
+	return err;
+}
+
+static inline void *
+get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
+{
+	unsigned long usp;
+
+	/* Default to using normal stack.  */
+	usp = rdusp();
+
+	/* This is the X/Open sanctioned signal stack switching.  */
+	if (ka->sa.sa_flags & SA_ONSTACK) {
+		if (!sas_ss_flags(usp))
+			usp = current->sas_ss_sp + current->sas_ss_size;
+	}
+	return (void *)((usp - frame_size) & -8UL);
+}
+
+static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
+			  struct pt_regs *regs)
+{
+	struct rt_sigframe *frame;
+	int err = 0;
+	int usig;
+	int sig = ksig->sig;
+	unsigned char *ret;
+
+	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto give_sigsegv;
+
+	usig = current_thread_info()->exec_domain
+		&& current_thread_info()->exec_domain->signal_invmap
+		&& sig < 32
+		? current_thread_info()->exec_domain->signal_invmap[sig]
+		: sig;
+
+	err |= __put_user(usig, &frame->sig);
+	if (err)
+		goto give_sigsegv;
+
+	err |= __put_user(&frame->info, &frame->pinfo);
+	err |= __put_user(&frame->uc, &frame->puc);
+	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+	if (err)
+		goto give_sigsegv;
+
+	/* Create the ucontext.  */
+	err |= __put_user(0, &frame->uc.uc_flags);
+	err |= __put_user(0, &frame->uc.uc_link);
+	err |= __save_altstack(&frame->uc.uc_stack, rdusp());
+	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
+	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+	if (err)
+		goto give_sigsegv;
+
+	/* Set up to return from userspace.  */
+	ret = frame->retcode;
+	if (ksig->ka.sa.sa_flags & SA_RESTORER)
+		ret = (unsigned char *)(ksig->ka.sa.sa_restorer);
+	else {
+		/* sub.l er0,er0; mov.b #__NR_rt_sigreturn,r0l; trapa #0 */
+		err |= __put_user(0x1a80f800 + (__NR_rt_sigreturn & 0xff),
+				  (unsigned long *)(frame->retcode + 0));
+		err |= __put_user(0x5700,
+				  (unsigned short *)(frame->retcode + 4));
+	}
+	err |= __put_user(ret, &frame->pretcode);
+
+	if (err)
+		goto give_sigsegv;
+
+	/* Set up registers for signal handler */
+	wrusp((unsigned long) frame);
+	regs->pc  = (unsigned long) ksig->ka.sa.sa_handler;
+	regs->er0 = (current_thread_info()->exec_domain
+		     && current_thread_info()->exec_domain->signal_invmap
+		     && sig < 32
+		     ? current_thread_info()->exec_domain->signal_invmap[sig]
+		     : sig);
+	regs->er1 = (unsigned long)&(frame->info);
+	regs->er2 = (unsigned long)&frame->uc;
+	regs->er5 = current->mm->start_data;	/* GOT base */
+
+	return 0;
+
+give_sigsegv:
+	force_sigsegv(sig, current);
+	return -EFAULT;
+}
+
+static void
+handle_restart(struct pt_regs *regs, struct k_sigaction *ka)
+{
+	switch (regs->er0) {
+	case -ERESTARTNOHAND:
+		if (!ka)
+			goto do_restart;
+		regs->er0 = -EINTR;
+		break;
+	case -ERESTART_RESTARTBLOCK:
+		if (!ka) {
+			regs->er0 = __NR_restart_syscall;
+			regs->pc -= 2;
+		} else
+			regs->er0 = -EINTR;
+		break;
+	case -ERESTARTSYS:
+		if (!(ka->sa.sa_flags & SA_RESTART)) {
+			regs->er0 = -EINTR;
+			break;
+		}
+		/* fallthrough */
+	case -ERESTARTNOINTR:
+do_restart:
+		regs->er0 = regs->orig_er0;
+		regs->pc -= 2;
+		break;
+	}
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+static void
+handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+	sigset_t *oldset = sigmask_to_save();
+	int ret;
+	/* are we from a system call? */
+	if (regs->orig_er0 >= 0)
+		handle_restart(regs, &ksig->ka);
+
+	ret = setup_rt_frame(ksig, oldset, regs);
+
+	signal_setup_done(ret, ksig, 0);
+}
+
+/*
+ * 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.
+ */
+static void do_signal(struct pt_regs *regs)
+{
+	struct ksignal ksig;
+
+	/*
+	 * 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 ((regs->ccr & 0x10))
+		return;
+
+	current->thread.esp0 = (unsigned long) regs;
+
+	if (get_signal(&ksig)) {
+		/* Whee!  Actually deliver the signal.  */
+		handle_signal(&ksig, regs);
+		return;
+	}
+	/* Did we come from a system call? */
+	if (regs->orig_er0 >= 0)
+		handle_restart(regs, NULL);
+
+	/* If there's no signal to deliver, we just restore the saved mask.  */
+	restore_saved_sigmask();
+}
+
+asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
+{
+	if (thread_info_flags & _TIF_SIGPENDING)
+		do_signal(regs);
+
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+		clear_thread_flag(TIF_NOTIFY_RESUME);
+		tracehook_notify_resume(regs);
+	}
+}
-- 
2.1.3