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Subject[PATCH v7 21/37] nds32: Signal handling support
Date
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 | 60 ++++++
arch/nds32/kernel/signal.c | 324 +++++++++++++++++++++++++++++++
2 files changed, 384 insertions(+)
create mode 100644 arch/nds32/include/uapi/asm/sigcontext.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 000000000000..00567b237b0c
--- /dev/null
+++ b/arch/nds32/include/uapi/asm/sigcontext.h
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#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/kernel/signal.c b/arch/nds32/kernel/signal.c
new file mode 100644
index 000000000000..5d01f6e33cb8
--- /dev/null
+++ b/arch/nds32/kernel/signal.c
@@ -0,0 +1,324 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#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
+
+ /*
+ * Avoid sys_rt_sigreturn() restarting.
+ */
+ forget_syscall(regs);
+ return err;
+}
+
+asmlinkage long 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;
+
+ /* Default to using normal stack */
+ sp = regs->sp;
+
+ /*
+ * If we are on the alternate signal stack and would overflow it, don't.
+ * Return an always-bogus address instead so we will die with SIGSEGV.
+ */
+ if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
+ return (void __user __force *)(-1UL);
+
+ /* This is the X/Open sanctioned signal stack switching. */
+ sp = (sigsp(sp, ksig) - framesize);
+
+ /*
+ * nds32 mandates 8-byte alignment
+ */
+ sp &= ~0x7UL;
+
+ return (void __user *)sp;
+}
+
+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;
+
+ 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 (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ return -EFAULT;
+
+ __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 (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+ 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();
+
+ if (in_syscall(regs)) {
+ /* Avoid additional syscall restarting via ret_slow_syscall. */
+ forget_syscall(regs);
+
+ switch (regs->uregs[0]) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ regs->uregs[0] = -EINTR;
+ break;
+ case -ERESTARTSYS:
+ if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
+ regs->uregs[0] = -EINTR;
+ break;
+ }
+ case -ERESTARTNOINTR:
+ regs->uregs[0] = regs->orig_r0;
+ regs->ipc -= 4;
+ break;
+ }
+ }
+ /*
+ * Set up the stack frame
+ */
+ 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.
+ *
+ * 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)
+{
+ struct ksignal ksig;
+
+ if (get_signal(&ksig)) {
+ handle_signal(&ksig, regs);
+ return;
+ }
+
+ /*
+ * If we were from a system call, check for system call restarting...
+ */
+ if (in_syscall(regs)) {
+ /* Restart the system call - no handlers present */
+
+ /* Avoid additional syscall restarting via ret_slow_syscall. */
+ forget_syscall(regs);
+
+ switch (regs->uregs[0]) {
+ case -ERESTART_RESTARTBLOCK:
+ regs->uregs[15] = __NR_restart_syscall;
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ regs->uregs[0] = regs->orig_r0;
+ regs->ipc -= 0x4;
+ break;
+ }
+ }
+ restore_saved_sigmask();
+}
+
+asmlinkage void
+do_notify_resume(struct pt_regs *regs, unsigned int thread_flags)
+{
+ if (thread_flags & _TIF_SIGPENDING)
+ do_signal(regs);
+
+ if (thread_flags & _TIF_NOTIFY_RESUME) {
+ clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(regs);
+ }
+}
--
2.16.1
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