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Subject[PATCH v6 18/29] nios2: Signal handling support
Date
This patch adds support for signal handling.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
---
arch/nios2/include/asm/signal.h | 22 +++
arch/nios2/include/asm/ucontext.h | 32 +++
arch/nios2/include/uapi/asm/sigcontext.h | 28 +++
arch/nios2/include/uapi/asm/signal.h | 23 +++
arch/nios2/kernel/signal.c | 323 +++++++++++++++++++++++++++++++
5 files changed, 428 insertions(+)
create mode 100644 arch/nios2/include/asm/signal.h
create mode 100644 arch/nios2/include/asm/ucontext.h
create mode 100644 arch/nios2/include/uapi/asm/sigcontext.h
create mode 100644 arch/nios2/include/uapi/asm/signal.h
create mode 100644 arch/nios2/kernel/signal.c

diff --git a/arch/nios2/include/asm/signal.h b/arch/nios2/include/asm/signal.h
new file mode 100644
index 0000000..bbcf11e
--- /dev/null
+++ b/arch/nios2/include/asm/signal.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright Altera Corporation (C) 2013. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#ifndef _NIOS2_SIGNAL_H
+#define _NIOS2_SIGNAL_H
+
+#include <uapi/asm/signal.h>
+
+#endif /* _NIOS2_SIGNAL_H */
diff --git a/arch/nios2/include/asm/ucontext.h b/arch/nios2/include/asm/ucontext.h
new file mode 100644
index 0000000..2c87614
--- /dev/null
+++ b/arch/nios2/include/asm/ucontext.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd
+ *
+ * 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.
+ */
+
+#ifndef _ASM_NIOS2_UCONTEXT_H
+#define _ASM_NIOS2_UCONTEXT_H
+
+typedef int greg_t;
+#define NGREG 32
+typedef greg_t gregset_t[NGREG];
+
+struct mcontext {
+ int version;
+ gregset_t gregs;
+};
+
+#define MCONTEXT_VERSION 2
+
+struct ucontext {
+ unsigned long uc_flags;
+ struct ucontext *uc_link;
+ stack_t uc_stack;
+ struct mcontext uc_mcontext;
+ sigset_t uc_sigmask; /* mask last for extensibility */
+};
+
+#endif
diff --git a/arch/nios2/include/uapi/asm/sigcontext.h b/arch/nios2/include/uapi/asm/sigcontext.h
new file mode 100644
index 0000000..7b8bb41
--- /dev/null
+++ b/arch/nios2/include/uapi/asm/sigcontext.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2004, Microtronix Datacom Ltd.
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for more
+ * details.
+ */
+
+#ifndef _ASM_NIOS2_SIGCONTEXT_H
+#define _ASM_NIOS2_SIGCONTEXT_H
+
+#include <asm/ptrace.h>
+
+struct sigcontext {
+ struct pt_regs regs;
+ unsigned long sc_mask; /* old sigmask */
+};
+
+#endif
diff --git a/arch/nios2/include/uapi/asm/signal.h b/arch/nios2/include/uapi/asm/signal.h
new file mode 100644
index 0000000..f29ee63
--- /dev/null
+++ b/arch/nios2/include/uapi/asm/signal.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright Altera Corporation (C) 2013. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#ifndef _ASM_NIOS2_SIGNAL_H
+#define _ASM_NIOS2_SIGNAL_H
+
+#define SA_RESTORER 0x04000000
+#include <asm-generic/signal.h>
+
+#endif /* _ASM_NIOS2_SIGNAL_H */
diff --git a/arch/nios2/kernel/signal.c b/arch/nios2/kernel/signal.c
new file mode 100644
index 0000000..f9d2788
--- /dev/null
+++ b/arch/nios2/kernel/signal.c
@@ -0,0 +1,323 @@
+/*
+ * Copyright (C) 2013-2014 Altera Corporation
+ * Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd
+ * 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.
+ */
+
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/uaccess.h>
+#include <linux/unistd.h>
+#include <linux/personality.h>
+#include <linux/tracehook.h>
+
+#include <asm/ucontext.h>
+#include <asm/cacheflush.h>
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+/*
+ * 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 {
+ struct siginfo info;
+ struct ucontext uc;
+};
+
+static inline int rt_restore_ucontext(struct pt_regs *regs,
+ struct switch_stack *sw,
+ struct ucontext *uc, int *pr2)
+{
+ int temp;
+ greg_t *gregs = uc->uc_mcontext.gregs;
+ int err;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+ err = __get_user(temp, &uc->uc_mcontext.version);
+ if (temp != MCONTEXT_VERSION)
+ goto badframe;
+ /* restore passed registers */
+ err |= __get_user(regs->r1, &gregs[0]);
+ err |= __get_user(regs->r2, &gregs[1]);
+ err |= __get_user(regs->r3, &gregs[2]);
+ err |= __get_user(regs->r4, &gregs[3]);
+ err |= __get_user(regs->r5, &gregs[4]);
+ err |= __get_user(regs->r6, &gregs[5]);
+ err |= __get_user(regs->r7, &gregs[6]);
+ err |= __get_user(regs->r8, &gregs[7]);
+ err |= __get_user(regs->r9, &gregs[8]);
+ err |= __get_user(regs->r10, &gregs[9]);
+ err |= __get_user(regs->r11, &gregs[10]);
+ err |= __get_user(regs->r12, &gregs[11]);
+ err |= __get_user(regs->r13, &gregs[12]);
+ err |= __get_user(regs->r14, &gregs[13]);
+ err |= __get_user(regs->r15, &gregs[14]);
+ err |= __get_user(sw->r16, &gregs[15]);
+ err |= __get_user(sw->r17, &gregs[16]);
+ err |= __get_user(sw->r18, &gregs[17]);
+ err |= __get_user(sw->r19, &gregs[18]);
+ err |= __get_user(sw->r20, &gregs[19]);
+ err |= __get_user(sw->r21, &gregs[20]);
+ err |= __get_user(sw->r22, &gregs[21]);
+ err |= __get_user(sw->r23, &gregs[22]);
+ /* gregs[23] is handled below */
+ err |= __get_user(sw->fp, &gregs[24]); /* Verify, should this be
+ settable */
+ err |= __get_user(sw->gp, &gregs[25]); /* Verify, should this be
+ settable */
+
+ err |= __get_user(temp, &gregs[26]); /* Not really necessary no user
+ settable bits */
+ err |= __get_user(regs->ea, &gregs[27]);
+
+ err |= __get_user(regs->ra, &gregs[23]);
+ err |= __get_user(regs->sp, &gregs[28]);
+
+ regs->orig_r2 = -1; /* disable syscall checks */
+
+ err |= restore_altstack(&uc->uc_stack);
+ if (err)
+ goto badframe;
+
+ *pr2 = regs->r2;
+ return err;
+
+badframe:
+ return 1;
+}
+
+asmlinkage int do_rt_sigreturn(struct switch_stack *sw)
+{
+ struct pt_regs *regs = (struct pt_regs *)(sw + 1);
+ /* Verify, can we follow the stack back */
+ struct rt_sigframe *frame = (struct rt_sigframe *) regs->sp;
+ sigset_t set;
+ 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;
+
+ set_current_blocked(&set);
+
+ if (rt_restore_ucontext(regs, sw, &frame->uc, &rval))
+ goto badframe;
+
+ return rval;
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+static inline int rt_setup_ucontext(struct ucontext *uc, struct pt_regs *regs)
+{
+ struct switch_stack *sw = (struct switch_stack *)regs - 1;
+ greg_t *gregs = uc->uc_mcontext.gregs;
+ int err = 0;
+
+ err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
+ err |= __put_user(regs->r1, &gregs[0]);
+ err |= __put_user(regs->r2, &gregs[1]);
+ err |= __put_user(regs->r3, &gregs[2]);
+ err |= __put_user(regs->r4, &gregs[3]);
+ err |= __put_user(regs->r5, &gregs[4]);
+ err |= __put_user(regs->r6, &gregs[5]);
+ err |= __put_user(regs->r7, &gregs[6]);
+ err |= __put_user(regs->r8, &gregs[7]);
+ err |= __put_user(regs->r9, &gregs[8]);
+ err |= __put_user(regs->r10, &gregs[9]);
+ err |= __put_user(regs->r11, &gregs[10]);
+ err |= __put_user(regs->r12, &gregs[11]);
+ err |= __put_user(regs->r13, &gregs[12]);
+ err |= __put_user(regs->r14, &gregs[13]);
+ err |= __put_user(regs->r15, &gregs[14]);
+ err |= __put_user(sw->r16, &gregs[15]);
+ err |= __put_user(sw->r17, &gregs[16]);
+ err |= __put_user(sw->r18, &gregs[17]);
+ err |= __put_user(sw->r19, &gregs[18]);
+ err |= __put_user(sw->r20, &gregs[19]);
+ err |= __put_user(sw->r21, &gregs[20]);
+ err |= __put_user(sw->r22, &gregs[21]);
+ err |= __put_user(sw->r23, &gregs[22]);
+ err |= __put_user(regs->ra, &gregs[23]);
+ err |= __put_user(sw->fp, &gregs[24]);
+ err |= __put_user(sw->gp, &gregs[25]);
+ err |= __put_user(regs->ea, &gregs[27]);
+ err |= __put_user(regs->sp, &gregs[28]);
+ return err;
+}
+
+static inline void *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
+ size_t frame_size)
+{
+ unsigned long usp;
+
+ /* Default to using normal stack. */
+ usp = regs->sp;
+
+ /* This is the X/Open sanctioned signal stack switching. */
+ usp = sigsp(usp, ksig);
+
+ /* Verify, is it 32 or 64 bit aligned */
+ 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;
+
+ frame = get_sigframe(ksig, regs, sizeof(*frame));
+
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+ /* 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, regs->sp);
+ err |= rt_setup_ucontext(&frame->uc, regs);
+ err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up to return from userspace; jump to fixed address sigreturn
+ trampoline on kuser page. */
+ regs->ra = (unsigned long) (0x1040);
+
+ /* Set up registers for signal handler */
+ regs->sp = (unsigned long) frame;
+ regs->r4 = (unsigned long) ksig->sig;
+ regs->r5 = (unsigned long) &frame->info;
+ regs->r6 = (unsigned long) &frame->uc;
+ regs->ea = (unsigned long) ksig->ka.sa.sa_handler;
+ return 0;
+
+give_sigsegv:
+ force_sigsegv(ksig->sig, current);
+ return -EFAULT;
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+ int ret;
+ sigset_t *oldset = sigmask_to_save();
+
+ /* set up the stack frame */
+ ret = setup_rt_frame(ksig, oldset, regs);
+
+ signal_setup_done(ret, ksig, 0);
+}
+
+static int do_signal(struct pt_regs *regs)
+{
+ unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
+ int restart = 0;
+ struct ksignal ksig;
+
+ current->thread.kregs = regs;
+
+ /*
+ * If we were from a system call, check for system call restarting...
+ */
+ if (regs->orig_r2 >= 0) {
+ continue_addr = regs->ea;
+ restart_addr = continue_addr - 4;
+ retval = regs->r2;
+
+ /*
+ * Prepare for system call restart. We do this here so that a
+ * debugger will see the already changed PC.
+ */
+ switch (retval) {
+ case ERESTART_RESTARTBLOCK:
+ restart = -2;
+ case ERESTARTNOHAND:
+ case ERESTARTSYS:
+ case ERESTARTNOINTR:
+ restart++;
+ regs->r2 = regs->orig_r2;
+ regs->r7 = regs->orig_r7;
+ regs->ea = restart_addr;
+ break;
+ }
+ }
+
+ if (get_signal(&ksig)) {
+ /* handler */
+ if (unlikely(restart && regs->ea == restart_addr)) {
+ if (retval == ERESTARTNOHAND ||
+ retval == ERESTART_RESTARTBLOCK ||
+ (retval == ERESTARTSYS
+ && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
+ regs->r2 = EINTR;
+ regs->r7 = 1;
+ regs->ea = continue_addr;
+ }
+ }
+ handle_signal(&ksig, regs);
+ return 0;
+ }
+
+ /*
+ * No handler present
+ */
+ if (unlikely(restart) && regs->ea == restart_addr) {
+ regs->ea = continue_addr;
+ regs->r2 = __NR_restart_syscall;
+ }
+
+ /*
+ * If there's no signal to deliver, we just put the saved sigmask back.
+ */
+ restore_saved_sigmask();
+
+ return restart;
+}
+
+asmlinkage int do_notify_resume(struct pt_regs *regs)
+{
+ /*
+ * 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 0;
+
+ if (test_thread_flag(TIF_SIGPENDING)) {
+ int restart = do_signal(regs);
+
+ if (unlikely(restart)) {
+ /*
+ * Restart without handlers.
+ * Deal with it without leaving
+ * the kernel space.
+ */
+ return restart;
+ }
+ } else if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
+ tracehook_notify_resume(regs);
+
+ return 0;
+}
--
1.8.2.1


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