MIPS: tlb-r3k: Also invalidate wired TLB entries on boot

Most R3k processor implementations have their 8 first TLB entries fixed
as wired, so we always skip them in TLB invalidation.  That however
means any leftover entries present there at boot will stay throughout
the life of the kernel, unless replaced with new ones.

So rename `local_flush_tlb_all' to `local_flush_tlb_from' and make it
accept the TLB entry to start from.  Then use 0 initially at bootstrap,
and the first regular entry later on, bypassing any wired entries.
Wrap the latter arrangement into a new `local_flush_tlb_all' entry
point.

There is no need to disable interrupts in the call made from `tlb_init'
because it's made before the interrupt subsystem has been initialised;
this is also true for secondary processors, should we ever support R3k
SMP.  So move this piece of code to new `local_flush_tlb_all'.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10194/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/mm/tlb-r3k.c

@@ -39,20 +39,12 @@ extern void build_tlb_refill_handler(void);
 int r3k_have_wired_reg;		/* should be in cpu_data? */
 
 /* TLB operations. */
-void local_flush_tlb_all(void)
+static void local_flush_tlb_from(int entry)
 {
-	unsigned long flags;
 	unsigned long old_ctx;
-	int entry;
 
-#ifdef DEBUG_TLB
-	printk("[tlball]");
-#endif
-
-	local_irq_save(flags);
 	old_ctx = read_c0_entryhi() & ASID_MASK;
 	write_c0_entrylo0(0);
-	entry = r3k_have_wired_reg ? read_c0_wired() : 8;
 	for (; entry < current_cpu_data.tlbsize; entry++) {
 		write_c0_index(entry << 8);
 		write_c0_entryhi((entry | 0x80000) << 12);
@@ -60,6 +52,17 @@ void local_flush_tlb_all(void)
 		tlb_write_indexed();
 	}
 	write_c0_entryhi(old_ctx);
+}
+
+void local_flush_tlb_all(void)
+{
+	unsigned long flags;
+
+#ifdef DEBUG_TLB
+	printk("[tlball]");
+#endif
+	local_irq_save(flags);
+	local_flush_tlb_from(r3k_have_wired_reg ? read_c0_wired() : 8);
 	local_irq_restore(flags);
 }
 
@@ -277,7 +280,6 @@ void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 
 void tlb_init(void)
 {
-	local_flush_tlb_all();
-
+	local_flush_tlb_from(0);
 	build_tlb_refill_handler();
 }