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-rw-r--r--arch/csky/kernel/signal.c347
1 files changed, 347 insertions, 0 deletions
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
new file mode 100644
index 000000000000..66e1b729b10b
--- /dev/null
+++ b/arch/csky/kernel/signal.c
@@ -0,0 +1,347 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#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 <linux/freezer.h>
+#include <linux/uaccess.h>
+
+#include <asm/setup.h>
+#include <asm/pgtable.h>
+#include <asm/traps.h>
+#include <asm/ucontext.h>
+#include <asm/vdso.h>
+
+#include <abi/regdef.h>
+
+#ifdef CONFIG_CPU_HAS_FPU
+#include <abi/fpu.h>
+
+static int restore_fpu_state(struct sigcontext *sc)
+{
+ int err = 0;
+ struct user_fp user_fp;
+
+ err = copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
+
+ restore_from_user_fp(&user_fp);
+
+ return err;
+}
+
+static int save_fpu_state(struct sigcontext *sc)
+{
+ struct user_fp user_fp;
+
+ save_to_user_fp(&user_fp);
+
+ return copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
+}
+#else
+static inline int restore_fpu_state(struct sigcontext *sc) { return 0; }
+static inline int save_fpu_state(struct sigcontext *sc) { return 0; }
+#endif
+
+struct rt_sigframe {
+ int sig;
+ struct siginfo *pinfo;
+ void *puc;
+ struct siginfo info;
+ struct ucontext uc;
+};
+
+static int
+restore_sigframe(struct pt_regs *regs,
+ struct sigcontext *sc, int *pr2)
+{
+ int err = 0;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current_thread_info()->task->restart_block.fn = do_no_restart_syscall;
+
+ err |= copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
+
+ err |= restore_fpu_state(sc);
+
+ *pr2 = regs->a0;
+ return err;
+}
+
+asmlinkage int
+do_rt_sigreturn(void)
+{
+ sigset_t set;
+ int a0;
+ struct pt_regs *regs = current_pt_regs();
+ struct rt_sigframe *frame = (struct rt_sigframe *)(regs->usp);
+
+ if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+ if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ goto badframe;
+
+ sigdelsetmask(&set, (sigmask(SIGKILL) | sigmask(SIGSTOP)));
+ spin_lock_irq(&current->sighand->siglock);
+ current->blocked = set;
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+
+ if (restore_sigframe(regs, &frame->uc.uc_mcontext, &a0))
+ goto badframe;
+
+ return a0;
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+static int setup_sigframe(struct sigcontext *sc, struct pt_regs *regs)
+{
+ int err = 0;
+
+ err |= copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
+ err |= save_fpu_state(sc);
+
+ 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 = regs->usp;
+
+ /* This is the X/Open sanctioned signal stack switching. */
+ if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(usp)) {
+ if (!on_sig_stack(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;
+
+ struct csky_vdso *vdso = current->mm->context.vdso;
+
+ frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
+ if (!frame)
+ return 1;
+
+ err |= __put_user(ksig->sig, &frame->sig);
+ err |= __put_user(&frame->info, &frame->pinfo);
+ err |= __put_user(&frame->uc, &frame->puc);
+ 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 |= __put_user((void *)current->sas_ss_sp,
+ &frame->uc.uc_stack.ss_sp);
+ err |= __put_user(sas_ss_flags(regs->usp),
+ &frame->uc.uc_stack.ss_flags);
+ err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+ err |= setup_sigframe(&frame->uc.uc_mcontext, regs);
+ err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up registers for signal handler */
+ regs->usp = (unsigned long)frame;
+ regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
+ regs->lr = (unsigned long)vdso->rt_signal_retcode;
+
+adjust_stack:
+ regs->a0 = ksig->sig; /* first arg is signo */
+ regs->a1 = (unsigned long)(&(frame->info));
+ regs->a2 = (unsigned long)(&(frame->uc));
+ return err;
+
+give_sigsegv:
+ if (ksig->sig == SIGSEGV)
+ ksig->ka.sa.sa_handler = SIG_DFL;
+ force_sig(SIGSEGV, current);
+ goto adjust_stack;
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+static int
+handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+ int ret;
+ sigset_t *oldset = sigmask_to_save();
+
+ /*
+ * set up the stack frame, regardless of SA_SIGINFO,
+ * and pass info anyway.
+ */
+ ret = setup_rt_frame(ksig, oldset, regs);
+
+ if (ret != 0) {
+ force_sigsegv(ksig->sig, current);
+ return ret;
+ }
+
+ /* Block the signal if we were successful. */
+ spin_lock_irq(&current->sighand->siglock);
+ sigorsets(&current->blocked, &current->blocked, &ksig->ka.sa.sa_mask);
+ if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
+ sigaddset(&current->blocked, ksig->sig);
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+
+ return 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, int syscall)
+{
+ unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
+ 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 (!user_mode(regs))
+ return;
+
+ current->thread.esp0 = (unsigned long)regs;
+
+ /*
+ * If we were from a system call, check for system call restarting...
+ */
+ if (syscall) {
+ continue_addr = regs->pc;
+#if defined(__CSKYABIV2__)
+ restart_addr = continue_addr - 4;
+#else
+ restart_addr = continue_addr - 2;
+#endif
+ retval = regs->a0;
+
+ /*
+ * Prepare for system call restart. We do this here so that a
+ * debugger will see the already changed.
+ */
+ switch (retval) {
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ regs->a0 = regs->orig_a0;
+ regs->pc = restart_addr;
+ break;
+ case -ERESTART_RESTARTBLOCK:
+ regs->a0 = -EINTR;
+ break;
+ }
+ }
+
+ if (try_to_freeze())
+ goto no_signal;
+
+ /*
+ * Get the signal to deliver. When running under ptrace, at this
+ * point the debugger may change all our registers ...
+ */
+ if (get_signal(&ksig)) {
+ /*
+ * 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 (regs->pc == restart_addr) {
+ if (retval == -ERESTARTNOHAND ||
+ (retval == -ERESTARTSYS &&
+ !(ksig.ka.sa.sa_flags & SA_RESTART))) {
+ regs->a0 = -EINTR;
+ regs->pc = continue_addr;
+ }
+ }
+
+ /* Whee! Actually deliver the signal. */
+ if (handle_signal(&ksig, regs) == 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:
+ if (syscall) {
+ /*
+ * Handle restarting a different system call. As above,
+ * if a debugger has chosen to restart at a different PC,
+ * ignore the restart.
+ */
+ if (retval == -ERESTART_RESTARTBLOCK
+ && regs->pc == continue_addr) {
+#if defined(__CSKYABIV2__)
+ regs->regs[3] = __NR_restart_syscall;
+ regs->pc -= 4;
+#else
+ regs->regs[9] = __NR_restart_syscall;
+ regs->pc -= 2;
+#endif
+ }
+
+ /*
+ * 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(unsigned int thread_flags, struct pt_regs *regs, int syscall)
+{
+ if (thread_flags & _TIF_SIGPENDING)
+ do_signal(regs, syscall);
+
+ if (thread_flags & _TIF_NOTIFY_RESUME) {
+ clear_thread_flag(TIF_NOTIFY_RESUME);
+ tracehook_notify_resume(regs);
+ }
+}