RISC-V updates for v5.4-rc3

Some RISC-V fixes for v5.4-rc3:
 
 - Fix several bugs in the breakpoint trap handler
 
 - Drop an unnecessary loop around calls to preempt_schedule_irq()
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Merge tag 'riscv/for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Paul Walmsley:

 - Fix several bugs in the breakpoint trap handler

 - Drop an unnecessary loop around calls to preempt_schedule_irq()

* tag 'riscv/for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: entry: Remove unneeded need_resched() loop
  riscv: Correct the handling of unexpected ebreak in do_trap_break()
  riscv: avoid sending a SIGTRAP to a user thread trapped in WARN()
  riscv: avoid kernel hangs when trapped in BUG()

arch/riscv/kernel/entry.S

@@ -273,12 +273,11 @@ restore_all:
 resume_kernel:
 	REG_L s0, TASK_TI_PREEMPT_COUNT(tp)
 	bnez s0, restore_all
-need_resched:
 	REG_L s0, TASK_TI_FLAGS(tp)
 	andi s0, s0, _TIF_NEED_RESCHED
 	beqz s0, restore_all
 	call preempt_schedule_irq
-	j need_resched
+	j restore_all
 #endif
 
 work_pending:

arch/riscv/kernel/traps.c

@@ -124,24 +124,24 @@ static inline unsigned long get_break_insn_length(unsigned long pc)
 
 asmlinkage void do_trap_break(struct pt_regs *regs)
 {
-#ifdef CONFIG_GENERIC_BUG
 	if (!user_mode(regs)) {
 		enum bug_trap_type type;
 
 		type = report_bug(regs->sepc, regs);
 		switch (type) {
-		case BUG_TRAP_TYPE_NONE:
-			break;
+#ifdef CONFIG_GENERIC_BUG
 		case BUG_TRAP_TYPE_WARN:
 			regs->sepc += get_break_insn_length(regs->sepc);
-			break;
+			return;
 		case BUG_TRAP_TYPE_BUG:
+#endif /* CONFIG_GENERIC_BUG */
+		default:
 			die(regs, "Kernel BUG");
 		}
+	} else {
+		force_sig_fault(SIGTRAP, TRAP_BRKPT,
+				(void __user *)(regs->sepc));
 	}
-#endif /* CONFIG_GENERIC_BUG */
-
-	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc));
 }
 
 #ifdef CONFIG_GENERIC_BUG