1 files changed, 127 insertions, 216 deletions

diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
index 5a18940f0b09..04a43cfd4e09 100644
--- a/arch/csky/kernel/signal.c
+++ b/arch/csky/kernel/signal.c
@@ -1,26 +1,10 @@
 // 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/uaccess.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>
@@ -29,110 +13,117 @@
 
 #ifdef CONFIG_CPU_HAS_FPU
 #include <abi/fpu.h>
-
-static int restore_fpu_state(struct sigcontext *sc)
+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));
+	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)
+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));
+	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; }
+#define restore_fpu_state(sigcontext)	(0)
+#define save_fpu_state(sigcontext)	(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)
+static long restore_sigcontext(struct pt_regs *regs,
+	struct sigcontext __user *sc)
 {
 	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));
+	/* 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);
 
-	*pr2 = regs->a0;
 	return err;
 }
 
-asmlinkage int
-do_rt_sigreturn(void)
+SYSCALL_DEFINE0(rt_sigreturn)
 {
-	sigset_t set;
-	int a0;
 	struct pt_regs *regs = current_pt_regs();
-	struct rt_sigframe *frame = (struct rt_sigframe *)(regs->usp);
+	struct rt_sigframe __user *frame;
+	struct task_struct *task;
+	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;
 
-	sigdelsetmask(&set, (sigmask(SIGKILL) | sigmask(SIGSTOP)));
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&set);
+
+	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
+		goto badframe;
 
-	if (restore_sigframe(regs, &frame->uc.uc_mcontext, &a0))
+	if (restore_altstack(&frame->uc.uc_stack))
 		goto badframe;
 
-	return a0;
+	return regs->a0;
 
 badframe:
-	force_sig(SIGSEGV, current);
+	task = current;
+	force_sig(SIGSEGV, task);
 	return 0;
 }
 
-static int setup_sigframe(struct sigcontext *sc, struct pt_regs *regs)
+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 |= __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)
+static inline void __user *get_sigframe(struct ksignal *ksig,
+	struct pt_regs *regs, size_t framesize)
 {
-	unsigned long usp;
+	unsigned long sp;
+	/* Default to using normal stack */
+	sp = regs->usp;
 
-	/* Default to using normal stack.  */
-	usp = 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.  */
-	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);
+	/* 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
@@ -140,208 +131,128 @@ 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;
+	frame = get_sigframe(ksig, regs, sizeof(*frame));
+	if (!access_ok(frame, sizeof(*frame)))
+		return -EFAULT;
 
-	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.  */
+	/* 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));
-
+	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)
-		goto give_sigsegv;
+		return -EFAULT;
 
-	/* 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;
+	/* Set up to return from userspace. */
+	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;
+	/*
+	 * 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 */
 
-give_sigsegv:
-	if (ksig->sig == SIGSEGV)
-		ksig->ka.sa.sa_handler = SIG_DFL;
-	force_sig(SIGSEGV, current);
-	goto adjust_stack;
+	return 0;
 }
 
-/*
- * OK, we're invoking a handler
- */
-static int
-handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 {
-	int ret;
 	sigset_t *oldset = sigmask_to_save();
+	int ret;
 
-	/*
-	 * set up the stack frame, regardless of SA_SIGINFO,
-	 * and pass info anyway.
-	 */
-	ret = setup_rt_frame(ksig, oldset, regs);
+	/* 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;
 
-	if (ret != 0) {
-		force_sigsegv(ksig->sig, current);
-		return ret;
+		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;
+		}
 	}
 
-	/* 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);
+	/* Set up the stack frame */
+	ret = setup_rt_frame(ksig, oldset, regs);
 
-	return 0;
+	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)
 {
-	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))
+	if (get_signal(&ksig)) {
+		/* Actually deliver the signal */
+		handle_signal(&ksig, regs);
 		return;
+	}
 
-	/*
-	 * If we were from a system call, check for system call restarting...
-	 */
+	/* Did we come from a system call? */
 	if (in_syscall(regs)) {
+		/* Avoid additional syscall restarting via ret_from_exception */
 		forget_syscall(regs);
 
-		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) {
+		/* Restart the system call - no handlers present */
+		switch (regs->a0) {
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:
 			regs->a0 = regs->orig_a0;
-			regs->pc = restart_addr;
+			regs->pc -= TRAP0_SIZE;
 			break;
 		case -ERESTART_RESTARTBLOCK:
-			regs->a0 = -EINTR;
+			regs->a0 = regs->orig_a0;
+			regs_syscallid(regs) = __NR_restart_syscall;
+			regs->pc -= TRAP0_SIZE;
 			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 there is no signal to deliver, we just put the saved
+	 * sigmask back.
 	 */
-	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 (in_syscall(regs)) {
-		forget_syscall(regs);
-
-		/*
-		 * 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);
-		}
-	}
+	restore_saved_sigmask();
 }
 
-asmlinkage void
-do_notify_resume(unsigned int thread_flags, struct pt_regs *regs)
+/*
+ * 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)
 {
-	if (thread_flags & _TIF_SIGPENDING)
+	/* Handle pending signal delivery */
+	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs);
 
-	if (thread_flags & _TIF_NOTIFY_RESUME) {
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
 	}