Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 24a9333..473de3a 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -1,16 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012 Regents of the University of California
- *
- *   This program is free software; you can redistribute it and/or
- *   modify it under the terms of the GNU General Public License
- *   as published by the Free Software Foundation, version 2.
- *
- *   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.
  */
 
+#include <linux/cpu.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/sched.h>
@@ -63,26 +56,27 @@
 		do_exit(SIGSEGV);
 }
 
-void do_trap(struct pt_regs *regs, int signo, int code,
-	unsigned long addr, struct task_struct *tsk)
+void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
 {
+	struct task_struct *tsk = current;
+
 	if (show_unhandled_signals && unhandled_signal(tsk, signo)
 	    && printk_ratelimit()) {
 		pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
 			tsk->comm, task_pid_nr(tsk), signo, code, addr);
-		print_vma_addr(KERN_CONT " in ", GET_IP(regs));
+		print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
 		pr_cont("\n");
 		show_regs(regs);
 	}
 
-	force_sig_fault(signo, code, (void __user *)addr, tsk);
+	force_sig_fault(signo, code, (void __user *)addr);
 }
 
 static void do_trap_error(struct pt_regs *regs, int signo, int code,
 	unsigned long addr, const char *str)
 {
 	if (user_mode(regs)) {
-		do_trap(regs, signo, code, addr, current);
+		do_trap(regs, signo, code, addr);
 	} else {
 		if (!fixup_exception(regs))
 			die(regs, str);
@@ -90,7 +84,7 @@
 }
 
 #define DO_ERROR_INFO(name, signo, code, str)				\
-asmlinkage void name(struct pt_regs *regs)				\
+asmlinkage __visible void name(struct pt_regs *regs)			\
 {									\
 	do_trap_error(regs, signo, code, regs->sepc, "Oops - " str);	\
 }
@@ -118,26 +112,23 @@
 DO_ERROR_INFO(do_trap_ecall_m,
 	SIGILL, ILL_ILLTRP, "environment call from M-mode");
 
-asmlinkage void do_trap_break(struct pt_regs *regs)
+static inline unsigned long get_break_insn_length(unsigned long pc)
 {
-#ifdef CONFIG_GENERIC_BUG
-	if (!user_mode(regs)) {
-		enum bug_trap_type type;
+	bug_insn_t insn;
 
-		type = report_bug(regs->sepc, regs);
-		switch (type) {
-		case BUG_TRAP_TYPE_NONE:
-			break;
-		case BUG_TRAP_TYPE_WARN:
-			regs->sepc += sizeof(bug_insn_t);
-			return;
-		case BUG_TRAP_TYPE_BUG:
-			die(regs, "Kernel BUG");
-		}
-	}
-#endif /* CONFIG_GENERIC_BUG */
+	if (probe_kernel_address((bug_insn_t *)pc, insn))
+		return 0;
+	return (((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL);
+}
 
-	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc), current);
+asmlinkage __visible void do_trap_break(struct pt_regs *regs)
+{
+	if (user_mode(regs))
+		force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->sepc);
+	else if (report_bug(regs->sepc, regs) == BUG_TRAP_TYPE_WARN)
+		regs->sepc += get_break_insn_length(regs->sepc);
+	else
+		die(regs, "Kernel BUG");
 }
 
 #ifdef CONFIG_GENERIC_BUG
@@ -145,11 +136,14 @@
 {
 	bug_insn_t insn;
 
-	if (pc < PAGE_OFFSET)
+	if (pc < VMALLOC_START)
 		return 0;
 	if (probe_kernel_address((bug_insn_t *)pc, insn))
 		return 0;
-	return (insn == __BUG_INSN);
+	if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
+		return (insn == __BUG_INSN_32);
+	else
+		return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
 }
 #endif /* CONFIG_GENERIC_BUG */
 
@@ -159,9 +153,9 @@
 	 * Set sup0 scratch register to 0, indicating to exception vector
 	 * that we are presently executing in the kernel
 	 */
-	csr_write(sscratch, 0);
+	csr_write(CSR_SSCRATCH, 0);
 	/* Set the exception vector address */
-	csr_write(stvec, &handle_exception);
+	csr_write(CSR_STVEC, &handle_exception);
 	/* Enable all interrupts */
-	csr_write(sie, -1);
+	csr_write(CSR_SIE, -1);
 }