Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
new file mode 100644
index 0000000..9b1b7c0
--- /dev/null
+++ b/arch/csky/kernel/signal.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/signal.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/tracehook.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 __user *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 __user *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
+#define restore_fpu_state(sigcontext) (0)
+#define save_fpu_state(sigcontext) (0)
+#endif
+
+struct rt_sigframe {
+ /*
+ * pad[3] is compatible with the same struct defined in
+ * gcc/libgcc/config/csky/linux-unwind.h
+ */
+ int pad[3];
+ struct siginfo info;
+ struct ucontext uc;
+};
+
+static long restore_sigcontext(struct pt_regs *regs,
+ struct sigcontext __user *sc)
+{
+ int err = 0;
+
+ /* sc_pt_regs is structured the same as the start of pt_regs */
+ err |= __copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
+
+ /* Restore the floating-point state. */
+ err |= restore_fpu_state(sc);
+
+ return err;
+}
+
+SYSCALL_DEFINE0(rt_sigreturn)
+{
+ struct pt_regs *regs = current_pt_regs();
+ struct rt_sigframe __user *frame;
+ sigset_t set;
+
+ /* Always make any pending restarted system calls return -EINTR */
+ current->restart_block.fn = do_no_restart_syscall;
+
+ frame = (struct rt_sigframe __user *)regs->usp;
+
+ if (!access_ok(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(regs, &frame->uc.uc_mcontext))
+ goto badframe;
+
+ if (restore_altstack(&frame->uc.uc_stack))
+ goto badframe;
+
+ return regs->a0;
+
+badframe:
+ force_sig(SIGSEGV);
+ return 0;
+}
+
+static int setup_sigcontext(struct rt_sigframe __user *frame,
+ struct pt_regs *regs)
+{
+ struct sigcontext __user *sc = &frame->uc.uc_mcontext;
+ 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 __user *get_sigframe(struct ksignal *ksig,
+ struct pt_regs *regs, size_t framesize)
+{
+ unsigned long sp;
+ /* Default to using normal stack */
+ sp = regs->usp;
+
+ /*
+ * 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;
+
+ /* Align the stack frame. */
+ sp &= -8UL;
+
+ return (void __user *)sp;
+}
+
+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, regs, sizeof(*frame));
+ if (!access_ok(frame, sizeof(*frame)))
+ return -EFAULT;
+
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+ /* Create the ucontext. */
+ err |= __put_user(0, &frame->uc.uc_flags);
+ err |= __put_user(NULL, &frame->uc.uc_link);
+ err |= __save_altstack(&frame->uc.uc_stack, regs->usp);
+ err |= setup_sigcontext(frame, regs);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+ if (err)
+ return -EFAULT;
+
+ /* Set up to return from userspace. */
+ regs->lr = (unsigned long)(vdso->rt_signal_retcode);
+
+ /*
+ * Set up registers for signal handler.
+ * Registers that we don't modify keep the value they had from
+ * user-space at the time we took the signal.
+ * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
+ * since some things rely on this (e.g. glibc's debug/segfault.c).
+ */
+ regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
+ regs->usp = (unsigned long)frame;
+ regs->a0 = ksig->sig; /* a0: signal number */
+ regs->a1 = (unsigned long)(&(frame->info)); /* a1: siginfo pointer */
+ regs->a2 = (unsigned long)(&(frame->uc)); /* a2: ucontext pointer */
+
+ return 0;
+}
+
+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 (in_syscall(regs)) {
+ /* Avoid additional syscall restarting via ret_from_exception */
+ forget_syscall(regs);
+
+ /* If so, check system call restarting.. */
+ switch (regs->a0) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ regs->a0 = -EINTR;
+ break;
+
+ case -ERESTARTSYS:
+ if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
+ regs->a0 = -EINTR;
+ break;
+ }
+ /* fallthrough */
+ case -ERESTARTNOINTR:
+ regs->a0 = regs->orig_a0;
+ regs->pc -= TRAP0_SIZE;
+ break;
+ }
+ }
+
+ /* Set up the stack frame */
+ ret = setup_rt_frame(ksig, oldset, regs);
+
+ signal_setup_done(ret, ksig, 0);
+}
+
+static void do_signal(struct pt_regs *regs)
+{
+ struct ksignal ksig;
+
+ if (get_signal(&ksig)) {
+ /* Actually deliver the signal */
+ handle_signal(&ksig, regs);
+ return;
+ }
+
+ /* Did we come from a system call? */
+ if (in_syscall(regs)) {
+ /* Avoid additional syscall restarting via ret_from_exception */
+ forget_syscall(regs);
+
+ /* Restart the system call - no handlers present */
+ switch (regs->a0) {
+ case -ERESTARTNOHAND:
+ case -ERESTARTSYS:
+ case -ERESTARTNOINTR:
+ regs->a0 = regs->orig_a0;
+ regs->pc -= TRAP0_SIZE;
+ break;
+ case -ERESTART_RESTARTBLOCK:
+ regs->a0 = regs->orig_a0;
+ regs_syscallid(regs) = __NR_restart_syscall;
+ regs->pc -= TRAP0_SIZE;
+ break;
+ }
+ }
+
+ /*
+ * If there is no signal to deliver, we just put the saved
+ * sigmask back.
+ */
+ restore_saved_sigmask();
+}
+
+/*
+ * notification of userspace execution resumption
+ * - triggered by the _TIF_WORK_MASK flags
+ */
+asmlinkage void do_notify_resume(struct pt_regs *regs,
+ unsigned long thread_info_flags)
+{
+ /* Handle pending signal delivery */
+ 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);
+ }
+}