MIPS: Refactor dumping of TLB registers for r3k/r4k

The TLB registers are dumped in a couble of places:
 - sysrq_tlbdump_single() - when dumping TLB state.
 - do_mcheck() - in response to a machine check error.

The main TLB registers also differ between r3k and r4k, but r4k appears
to be assumed.

Refactor this code into a dump_tlb_regs() function, implemented for both
r3k and r4k, and used by both of the above functions.

Fixes: d1e9a4f54735 ("MIPS: Add SysRq operation to dump TLBs on all CPUs")
Suggested-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10721/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/tlbdebug.h

@@ -11,6 +11,7 @@
 /*
  * TLB debugging functions:
  */
+extern void dump_tlb_regs(void);
 extern void dump_tlb_all(void);
 
 #endif /* __ASM_TLBDEBUG_H */

arch/mips/kernel/sysrq.c

@@ -21,24 +21,12 @@ static DEFINE_SPINLOCK(show_lock);
 
 static void sysrq_tlbdump_single(void *dummy)
 {
-	const int field = 2 * sizeof(unsigned long);
 	unsigned long flags;
 
 	spin_lock_irqsave(&show_lock, flags);
 
 	pr_info("CPU%d:\n", smp_processor_id());
-	pr_info("Index	: %0x\n", read_c0_index());
-	pr_info("Pagemask: %0x\n", read_c0_pagemask());
-	pr_info("EntryHi : %0*lx\n", field, read_c0_entryhi());
-	pr_info("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
-	pr_info("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
-	pr_info("Wired   : %0x\n", read_c0_wired());
-	pr_info("Pagegrain: %0x\n", read_c0_pagegrain());
-	if (cpu_has_htw) {
-		pr_info("PWField : %0*lx\n", field, read_c0_pwfield());
-		pr_info("PWSize  : %0*lx\n", field, read_c0_pwsize());
-		pr_info("PWCtl   : %0x\n", read_c0_pwctl());
-	}
+	dump_tlb_regs();
 	pr_info("\n");
 	dump_tlb_all();
 	pr_info("\n");

arch/mips/kernel/traps.c

@@ -1523,7 +1523,6 @@ asmlinkage void do_watch(struct pt_regs *regs)
 
 asmlinkage void do_mcheck(struct pt_regs *regs)
 {
-	const int field = 2 * sizeof(unsigned long);
 	int multi_match = regs->cp0_status & ST0_TS;
 	enum ctx_state prev_state;
 	mm_segment_t old_fs = get_fs();
@@ -1532,19 +1531,8 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
 	show_regs(regs);
 
 	if (multi_match) {
-		pr_err("Index	: %0x\n", read_c0_index());
-		pr_err("Pagemask: %0x\n", read_c0_pagemask());
-		pr_err("EntryHi : %0*lx\n", field, read_c0_entryhi());
-		pr_err("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
-		pr_err("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
-		pr_err("Wired   : %0x\n", read_c0_wired());
-		pr_err("Pagegrain: %0x\n", read_c0_pagegrain());
-		if (cpu_has_htw) {
-			pr_err("PWField : %0*lx\n", field, read_c0_pwfield());
-			pr_err("PWSize  : %0*lx\n", field, read_c0_pwsize());
-			pr_err("PWCtl   : %0x\n", read_c0_pwctl());
-		}
-		pr_err("\n");
+		dump_tlb_regs();
+		pr_info("\n");
 		dump_tlb_all();
 	}
 

arch/mips/lib/dump_tlb.c

@@ -13,6 +13,24 @@
 #include <asm/pgtable.h>
 #include <asm/tlbdebug.h>
 
+void dump_tlb_regs(void)
+{
+	const int field = 2 * sizeof(unsigned long);
+
+	pr_info("Index    : %0x\n", read_c0_index());
+	pr_info("PageMask : %0x\n", read_c0_pagemask());
+	pr_info("EntryHi  : %0*lx\n", field, read_c0_entryhi());
+	pr_info("EntryLo0 : %0*lx\n", field, read_c0_entrylo0());
+	pr_info("EntryLo1 : %0*lx\n", field, read_c0_entrylo1());
+	pr_info("Wired    : %0x\n", read_c0_wired());
+	pr_info("PageGrain: %0x\n", read_c0_pagegrain());
+	if (cpu_has_htw) {
+		pr_info("PWField  : %0*lx\n", field, read_c0_pwfield());
+		pr_info("PWSize   : %0*lx\n", field, read_c0_pwsize());
+		pr_info("PWCtl    : %0x\n", read_c0_pwctl());
+	}
+}
+
 static inline const char *msk2str(unsigned int mask)
 {
 	switch (mask) {

arch/mips/lib/r3k_dump_tlb.c

@@ -14,6 +14,17 @@
 #include <asm/pgtable.h>
 #include <asm/tlbdebug.h>
 
+extern int r3k_have_wired_reg;
+
+void dump_tlb_regs(void)
+{
+	pr_info("Index    : %0x\n", read_c0_index());
+	pr_info("EntryHi  : %0lx\n", read_c0_entryhi());
+	pr_info("EntryLo  : %0lx\n", read_c0_entrylo0());
+	if (r3k_have_wired_reg)
+		pr_info("Wired    : %0x\n", read_c0_wired());
+}
+
 static void dump_tlb(int first, int last)
 {
 	int	i;

arch/mips/mm/tlb-r3k.c

@@ -36,7 +36,7 @@ extern void build_tlb_refill_handler(void);
 		"nop\n\t"		\
 		".set	pop\n\t")
 
-static int r3k_have_wired_reg;			/* Should be in cpu_data? */
+int r3k_have_wired_reg;			/* Should be in cpu_data? */
 
 /* TLB operations. */
 static void local_flush_tlb_from(int entry)