MIPS: Use dedicated exception handler if CPU supports RI/XI exceptions

Use the regular tlb_do_page_fault_0 (no write) handler to handle
the RI and XI exceptions. Also skip the RI/XI validation check
on TLB load handler since it's redundant when the CPU has
unique RI/XI exceptions.

Singed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7339/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/traps.c

@@ -90,6 +90,7 @@ extern asmlinkage void handle_mt(void);
 extern asmlinkage void handle_dsp(void);
 extern asmlinkage void handle_mcheck(void);
 extern asmlinkage void handle_reserved(void);
+extern void tlb_do_page_fault_0(void);
 
 void (*board_be_init)(void);
 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
@@ -2114,6 +2115,12 @@ void __init trap_init(void)
 		set_except_vector(15, handle_fpe);
 
 	set_except_vector(16, handle_ftlb);
+
+	if (cpu_has_rixiex) {
+		set_except_vector(19, tlb_do_page_fault_0);
+		set_except_vector(20, tlb_do_page_fault_0);
+	}
+
 	set_except_vector(21, handle_msa);
 	set_except_vector(22, handle_mdmx);
 

arch/mips/mm/tlbex.c

@@ -1919,7 +1919,7 @@ static void build_r4000_tlb_load_handler(void)
 	if (m4kc_tlbp_war())
 		build_tlb_probe_entry(&p);
 
-	if (cpu_has_rixi) {
+	if (cpu_has_rixi && !cpu_has_rixiex) {
 		/*
 		 * If the page is not _PAGE_VALID, RI or XI could not
 		 * have triggered it.  Skip the expensive test..
@@ -1986,7 +1986,7 @@ static void build_r4000_tlb_load_handler(void)
 	build_pte_present(&p, &r, wr.r1, wr.r2, wr.r3, label_nopage_tlbl);
 	build_tlb_probe_entry(&p);
 
-	if (cpu_has_rixi) {
+	if (cpu_has_rixi && !cpu_has_rixiex) {
 		/*
 		 * If the page is not _PAGE_VALID, RI or XI could not
 		 * have triggered it.  Skip the expensive test..