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Subject[PATCH v2 16/35] nds32: Signal handling support
Date
From: Greentime Hu <greentime@andestech.com>

This patch adds support for signal handling.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
---
arch/nds32/include/uapi/asm/sigcontext.h | 73 ++++++
arch/nds32/include/uapi/asm/signal.h | 23 ++
arch/nds32/kernel/signal.c | 354 ++++++++++++++++++++++++++++++
3 files changed, 450 insertions(+)
create mode 100644 arch/nds32/include/uapi/asm/sigcontext.h
create mode 100644 arch/nds32/include/uapi/asm/signal.h
create mode 100644 arch/nds32/kernel/signal.c

diff --git a/arch/nds32/include/uapi/asm/sigcontext.h b/arch/nds32/include/uapi/asm/sigcontext.h
new file mode 100644
index 0000000..1c0dfcb
--- /dev/null
+++ b/arch/nds32/include/uapi/asm/sigcontext.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2005-2017 Andes Technology Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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. 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 _ASMNDS32_SIGCONTEXT_H
+#define _ASMNDS32_SIGCONTEXT_H
+
+/*
+ * Signal context structure - contains all info to do with the state
+ * before the signal handler was invoked. Note: only add new entries
+ * to the end of the structure.
+ */
+
+struct zol_struct {
+ unsigned long nds32_lc; /* $LC */
+ unsigned long nds32_le; /* $LE */
+ unsigned long nds32_lb; /* $LB */
+};
+
+struct sigcontext {
+ unsigned long trap_no;
+ unsigned long error_code;
+ unsigned long oldmask;
+ unsigned long nds32_r0;
+ unsigned long nds32_r1;
+ unsigned long nds32_r2;
+ unsigned long nds32_r3;
+ unsigned long nds32_r4;
+ unsigned long nds32_r5;
+ unsigned long nds32_r6;
+ unsigned long nds32_r7;
+ unsigned long nds32_r8;
+ unsigned long nds32_r9;
+ unsigned long nds32_r10;
+ unsigned long nds32_r11;
+ unsigned long nds32_r12;
+ unsigned long nds32_r13;
+ unsigned long nds32_r14;
+ unsigned long nds32_r15;
+ unsigned long nds32_r16;
+ unsigned long nds32_r17;
+ unsigned long nds32_r18;
+ unsigned long nds32_r19;
+ unsigned long nds32_r20;
+ unsigned long nds32_r21;
+ unsigned long nds32_r22;
+ unsigned long nds32_r23;
+ unsigned long nds32_r24;
+ unsigned long nds32_r25;
+ unsigned long nds32_fp; /* $r28 */
+ unsigned long nds32_gp; /* $r29 */
+ unsigned long nds32_lp; /* $r30 */
+ unsigned long nds32_sp; /* $r31 */
+ unsigned long nds32_ipc;
+ unsigned long fault_address;
+ unsigned long used_math_flag;
+ /* FPU Registers */
+ struct zol_struct zol;
+};
+
+#endif
diff --git a/arch/nds32/include/uapi/asm/signal.h b/arch/nds32/include/uapi/asm/signal.h
new file mode 100644
index 0000000..5ef6915
--- /dev/null
+++ b/arch/nds32/include/uapi/asm/signal.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2005-2017 Andes Technology Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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. 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 _ASMNDS32_SIGNAL_H
+#define _ASMNDS32_SIGNAL_H
+
+#define SA_RESTORER 0x04000000
+
+#include <asm-generic/signal.h>
+#endif
diff --git a/arch/nds32/kernel/signal.c b/arch/nds32/kernel/signal.c
new file mode 100644
index 0000000..a1ea2b1
--- /dev/null
+++ b/arch/nds32/kernel/signal.c
@@ -0,0 +1,354 @@
+/*
+ * Copyright (C) 2005-2017 Andes Technology Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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. 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/>.
+ */
+
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/ptrace.h>
+#include <linux/personality.h>
+#include <linux/freezer.h>
+#include <linux/tracehook.h>
+#include <linux/uaccess.h>
+
+#include <asm/cacheflush.h>
+#include <asm/ucontext.h>
+#include <asm/unistd.h>
+
+#include <asm/ptrace.h>
+#include <asm/vdso.h>
+
+struct rt_sigframe {
+ struct siginfo info;
+ struct ucontext uc;
+};
+
+static int restore_sigframe(struct pt_regs *regs,
+ struct rt_sigframe __user * sf)
+{
+ sigset_t set;
+ int err;
+
+ err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
+ if (err == 0) {
+ set_current_blocked(&set);
+ }
+
+ __get_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
+ __get_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
+ __get_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
+ __get_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
+ __get_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
+ __get_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
+ __get_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
+ __get_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
+ __get_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
+ __get_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
+ __get_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
+ __get_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
+ __get_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
+ __get_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
+ __get_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
+ __get_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
+ __get_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
+ __get_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
+ __get_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
+ __get_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
+ __get_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);
+ __get_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
+ __get_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
+ __get_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
+ __get_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
+ __get_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);
+
+ __get_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
+ __get_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
+ __get_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
+ __get_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
+ __get_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
+#if defined(CONFIG_HWZOL)
+ __get_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
+ __get_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
+ __get_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
+#endif
+
+ return err;
+}
+
+asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
+{
+ struct rt_sigframe __user *frame;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current->restart_block.fn = do_no_restart_syscall;
+
+ /*
+ * Since we stacked the signal on a 64-bit boundary,
+ * then 'sp' should be two-word aligned here. If it's
+ * not, then the user is trying to mess with us.
+ */
+ if (regs->sp & 7)
+ goto badframe;
+
+ frame = (struct rt_sigframe __user *)regs->sp;
+
+ if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+
+ if (restore_sigframe(regs, frame))
+ goto badframe;
+
+ if (restore_altstack(&frame->uc.uc_stack))
+ goto badframe;
+
+ return regs->uregs[0];
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+static int
+setup_sigframe(struct rt_sigframe __user * sf, struct pt_regs *regs,
+ sigset_t * set)
+{
+ int err = 0;
+
+
+ __put_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
+ __put_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
+ __put_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
+ __put_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
+ __put_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
+ __put_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
+ __put_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
+ __put_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
+ __put_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
+ __put_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
+ __put_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
+ __put_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
+ __put_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
+ __put_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
+ __put_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
+ __put_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
+ __put_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
+ __put_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
+ __put_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
+ __put_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
+ __put_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);
+
+ __put_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
+ __put_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
+ __put_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
+ __put_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
+ __put_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);
+ __put_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
+ __put_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
+ __put_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
+ __put_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
+ __put_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
+#if defined(CONFIG_HWZOL)
+ __put_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
+ __put_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
+ __put_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
+#endif
+
+ __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no,
+ err);
+ __put_user_error(current->thread.error_code,
+ &sf->uc.uc_mcontext.error_code, err);
+ __put_user_error(current->thread.address,
+ &sf->uc.uc_mcontext.fault_address, err);
+ __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
+
+ err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
+
+ return err;
+}
+
+static inline void __user *get_sigframe(struct ksignal *ksig,
+ struct pt_regs *regs, int framesize)
+{
+ unsigned long sp = sigsp(regs->sp, ksig);
+ void __user *frame;
+
+ /*
+ * nds32 mandates 8-byte alignment
+ */
+ frame = (void __user *)((sp - framesize) & ~7);
+
+ /*
+ * Check that we can actually write to the signal frame.
+ */
+ if (!access_ok(VERIFY_WRITE, frame, framesize))
+ frame = NULL;
+
+ return frame;
+}
+
+static int
+setup_return(struct pt_regs *regs, struct ksignal *ksig, void __user * frame)
+{
+ unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
+ unsigned long retcode;
+
+ if (ksig->ka.sa.sa_flags & SA_RESTORER)
+ retcode = (unsigned long)ksig->ka.sa.sa_restorer;
+ else
+ retcode = VDSO_SYMBOL(current->mm->context.vdso, rt_sigtramp);
+
+ regs->uregs[0] = ksig->sig;
+ regs->sp = (unsigned long)frame;
+ regs->lp = retcode;
+ regs->ipc = handler;
+
+ return 0;
+}
+
+static int
+setup_rt_frame(struct ksignal *ksig, sigset_t * set, struct pt_regs *regs)
+{
+ struct rt_sigframe __user *frame =
+ get_sigframe(ksig, regs, sizeof(*frame));
+ int err = 0;
+
+ if (!frame)
+ return 1;
+
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+ __put_user_error(0, &frame->uc.uc_flags, err);
+ __put_user_error(NULL, &frame->uc.uc_link, err);
+
+ err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
+ err |= setup_sigframe(frame, regs, set);
+ if (err == 0) {
+ setup_return(regs, ksig, frame);
+
+ if (err == 0) {
+ /*
+ * For realtime signals we must also set the second and third
+ * arguments for the signal handler.
+ * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
+ */
+ regs->uregs[1] = (unsigned long)&frame->info;
+ regs->uregs[2] = (unsigned long)&frame->uc;
+ }
+ }
+ return err;
+}
+
+/*
+ * 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);
+
+ /*
+ * Check that the resulting registers are actually sane.
+ */
+ ret |= !valid_user_regs(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.
+ *
+ * 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 int do_signal(struct pt_regs *regs, int syscall)
+{
+ unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
+ struct ksignal ksig;
+ int restart = 0;
+
+ /*
+ * If we were from a system call, check for system call restarting...
+ */
+ if (syscall) {
+ continue_addr = regs->ipc;
+ restart_addr = continue_addr - 4;
+ retval = regs->uregs[0];
+
+ /*
+ * Prepare for system call restart. We do this here so that a
+ * debugger will see the already changed PSW.
+ */
+ switch (retval) {
+ case -ERESTART_RESTARTBLOCK:
+ restart -= 2;
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ restart++;
+ regs->uregs[0] = regs->orig_r0;
+ regs->ipc = restart_addr;
+ break;
+ }
+ }
+
+ /*
+ * Get the signal to deliver. When running under ptrace, at this
+ * point the debugger may change all our registers ...
+ */
+ /*
+ * Depending on the signal settings we may need to revert the
+ * decision to restart the system call. But skip this if a
+ * debugger has chosen to restart at a different PC.
+ */
+ if (get_signal(&ksig)) {
+ if (unlikely(restart) && regs->ipc == restart_addr) {
+ if (retval == -ERESTARTNOHAND ||
+ retval == -ERESTART_RESTARTBLOCK
+ || (retval == -ERESTARTSYS
+ && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
+ regs->uregs[0] = -EINTR;
+ regs->ipc = continue_addr;
+ }
+ }
+ handle_signal(&ksig, regs);
+ } else {
+ restore_saved_sigmask();
+ if (unlikely(restart) && regs->ipc == restart_addr) {
+ regs->ipc = continue_addr;
+ return restart;
+ }
+ }
+ return 0;
+}
+
+asmlinkage int
+do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
+{
+ if (thread_flags & _TIF_SIGPENDING)
+ return do_signal(regs, syscall);
+
+ if (thread_flags & _TIF_NOTIFY_RESUME) {
+ clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(regs);
+ }
+ return 0;
+}
--
1.7.9.5
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