RISC-V updates for v5.4-rc4

Some RISC-V fixes for v5.4-rc4:
 
 - Fix the virtual memory layout so the fixaddr region doesn't overlap
   with other regions.  (This was originally intended to go in as part
   of an earlier patch, but I inadvertently dropped it during a
   rebase.)
 
 - Add the DT chosen/stdout-path property to the HiFive Unleashed DT
   file.  This is so "earlycon" can be specified with no arguments on
   the kernel command line, and the correct UART will be automatically
   selected.
 
 And two cleanup patches:
 
 - Simplify the code in our breakpoint trap handler.
 
 - Drop a comment in our TLB flush code that has caused some confusion.
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Merge tag 'riscv/for-v5.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Paul Walmsley:
 "Some RISC-V fixes:

   - Fix the virtual memory layout so the fixaddr region doesn't overlap
     with other regions. (This was originally intended to go in as part
     of an earlier patch, but I inadvertently dropped it during a
     rebase)

   - Add the DT chosen/stdout-path property to the HiFive Unleashed DT
     file. This is so "earlycon" can be specified with no arguments on
     the kernel command line, and the correct UART will be automatically
     selected.

  And two cleanup patches:

   - Simplify the code in our breakpoint trap handler.

   - Drop a comment in our TLB flush code that has caused some
     confusion"

* tag 'riscv/for-v5.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: fix virtual address overlapped in FIXADDR_START and VMEMMAP_START
  riscv: tlbflush: remove confusing comment on local_flush_tlb_all()
  riscv: dts: HiFive Unleashed: add default chosen/stdout-path
  riscv: remove the switch statement in do_trap_break()

arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts

@@ -13,6 +13,7 @@
 	compatible = "sifive,hifive-unleashed-a00", "sifive,fu540-c000";
 
 	chosen {
+		stdout-path = "serial0";
 	};
 
 	cpus {

arch/riscv/include/asm/pgtable.h

@@ -87,14 +87,6 @@ extern pgd_t swapper_pg_dir[];
 #define VMALLOC_END      (PAGE_OFFSET - 1)
 #define VMALLOC_START    (PAGE_OFFSET - VMALLOC_SIZE)
 
-#define FIXADDR_TOP      VMALLOC_START
-#ifdef CONFIG_64BIT
-#define FIXADDR_SIZE     PMD_SIZE
-#else
-#define FIXADDR_SIZE     PGDIR_SIZE
-#endif
-#define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)
-
 /*
  * Roughly size the vmemmap space to be large enough to fit enough
  * struct pages to map half the virtual address space. Then
@@ -108,6 +100,14 @@ extern pgd_t swapper_pg_dir[];
 
 #define vmemmap		((struct page *)VMEMMAP_START)
 
+#define FIXADDR_TOP      (VMEMMAP_START)
+#ifdef CONFIG_64BIT
+#define FIXADDR_SIZE     PMD_SIZE
+#else
+#define FIXADDR_SIZE     PGDIR_SIZE
+#endif
+#define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)
+
 /*
  * ZERO_PAGE is a global shared page that is always zero,
  * used for zero-mapped memory areas, etc.

arch/riscv/include/asm/tlbflush.h

@@ -10,10 +10,6 @@
 #include <linux/mm_types.h>
 #include <asm/smp.h>
 
-/*
- * Flush entire local TLB.  'sfence.vma' implicitly fences with the instruction
- * cache as well, so a 'fence.i' is not necessary.
- */
 static inline void local_flush_tlb_all(void)
 {
 	__asm__ __volatile__ ("sfence.vma" : : : "memory");

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)
 {
-	if (!user_mode(regs)) {
+	if (user_mode(regs)) {
+		force_sig_fault(SIGTRAP, TRAP_BRKPT,
+				(void __user *)(regs->sepc));
+		return;
+	}
+#ifdef CONFIG_GENERIC_BUG
+	{
 		enum bug_trap_type type;
 
 		type = report_bug(regs->sepc, regs);
-		switch (type) {
-#ifdef CONFIG_GENERIC_BUG
-		case BUG_TRAP_TYPE_WARN:
+		if (type == BUG_TRAP_TYPE_WARN) {
 			regs->sepc += get_break_insn_length(regs->sepc);
 			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 */
+
+	die(regs, "Kernel BUG");
 }
 
 #ifdef CONFIG_GENERIC_BUG