[src/trunk]: src/sys/arch/sh3/sh3 sh4_mmu_start - cosmetics.

[uwe <uwe%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/a34d66869da2
branches:  trunk
changeset: 936787:a34d66869da2
user:      uwe <uwe%NetBSD.org@localhost>
date:      Mon Aug 03 23:01:47 2020 +0000

description:
sh4_mmu_start - cosmetics.

Split construction of the initial MMUCR value into several assignments
for readability.  Same object code is generated.

diffstat:

 sys/arch/sh3/sh3/mmu_sh4.c |  23 +++++++++++++----------
 1 files changed, 13 insertions(+), 10 deletions(-)

diffs (63 lines):

diff -r 210899681e71 -r a34d66869da2 sys/arch/sh3/sh3/mmu_sh4.c
--- a/sys/arch/sh3/sh3/mmu_sh4.c        Mon Aug 03 22:43:52 2020 +0000
+++ b/sys/arch/sh3/sh3/mmu_sh4.c        Mon Aug 03 23:01:47 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mmu_sh4.c,v 1.19 2020/08/03 22:43:52 uwe Exp $ */
+/*     $NetBSD: mmu_sh4.c,v 1.20 2020/08/03 23:01:47 uwe Exp $ */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: mmu_sh4.c,v 1.19 2020/08/03 22:43:52 uwe Exp $");
+__KERNEL_RCSID(0, "$NetBSD: mmu_sh4.c,v 1.20 2020/08/03 23:01:47 uwe Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -41,12 +41,13 @@
 
 static __noinline void __sh4_tlb_assoc(uint32_t);
 
-#define        SH4_MMU_HAZARD  __asm volatile("nop;nop;nop;nop;nop;nop;nop;nop;")
-
 /* Must be inlined because we "call" it while running on P2 */
 static inline void __sh4_itlb_invalidate_all(void)
     __attribute__((always_inline));
 
+#define        SH4_MMU_HAZARD  __asm volatile("nop;nop;nop;nop;nop;nop;nop;nop;")
+
+
 
 static inline void
 __sh4_itlb_invalidate_all(void)
@@ -61,6 +62,7 @@
 void
 sh4_mmu_start(void)
 {
+       uint32_t cr;
 
        /* Zero clear all TLB entry */
        _reg_write_4(SH4_MMUCR, 0);     /* zero wired entry */
@@ -69,13 +71,14 @@
        /* Set current ASID to 0 */
        sh_tlb_set_asid(0);
 
-       /*
-        * User can't access store queue
-        * make wired entry for u-area.
-        */
-       _reg_write_4(SH4_MMUCR, SH4_MMUCR_AT | SH4_MMUCR_TI | SH4_MMUCR_SQMD |
-           (SH4_UTLB_ENTRY - UPAGES) << SH4_MMUCR_URB_SHIFT);
+       cr  = SH4_MMUCR_AT;     /* address translation enabled */
+       cr |= SH4_MMUCR_TI;     /* TLB invalidate */
+       cr |= SH4_MMUCR_SQMD;   /* store queues not accessible to user */
 
+       /* resereve TLB entries for wired u-area (cf. sh4_switch_resume) */
+       cr |= (SH4_UTLB_ENTRY - UPAGES) << SH4_MMUCR_URB_SHIFT;
+
+       _reg_write_4(SH4_MMUCR, cr);
        SH4_MMU_HAZARD;
 }