From: kettenis <kettenis@openbsd.org>
Date: Wed, 3 Aug 2016 07:05:05 +0000 (+0000)
Subject: The ARMv7 architecture deprecates the separate Instruction and Data TLB
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=0fa0531171a579c99b53869e8f36290bde3a7456;p=openbsd

The ARMv7 architecture deprecates the separate Instruction and Data TLB
maintanenance instruction and recommends to only use the instructions that
operate on the unified TLB.  Those instructions will flush both TLBs on
implementations that still have separate Instruction and Data TLBs.  Switch
the TLB maintenance primitives over to use those.  This allows us to reduce
the number of primitives on armv7.  We still keep separate "ID" and "D"
variants as we still have to flush the branch predictor when changing the
mappings of pages that contain instructions.

ok jsg@
---

diff --git a/sys/arch/arm/arm/cpufunc.c b/sys/arch/arm/arm/cpufunc.c
index 18c323e0138..92dec5951ba 100644
--- a/sys/arch/arm/arm/cpufunc.c
+++ b/sys/arch/arm/arm/cpufunc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpufunc.c,v 1.42 2016/07/31 03:49:51 jsg Exp $	*/
+/*	$OpenBSD: cpufunc.c,v 1.43 2016/08/03 07:05:05 kettenis Exp $	*/
 /*	$NetBSD: cpufunc.c,v 1.65 2003/11/05 12:53:15 scw Exp $	*/
 
 /*
@@ -109,8 +109,8 @@ struct cpu_functions armv7_cpufuncs = {
 
 	armv7_tlb_flushID,		/* tlb_flushID		*/
 	armv7_tlb_flushID_SE,		/* tlb_flushID_SE	*/
-	armv7_tlb_flushI,		/* tlb_flushI		*/
-	armv7_tlb_flushI_SE,		/* tlb_flushI_SE	*/
+	armv7_tlb_flushID,		/* tlb_flushI		*/
+	armv7_tlb_flushID_SE,		/* tlb_flushI_SE	*/
 	armv7_tlb_flushD,		/* tlb_flushD		*/
 	armv7_tlb_flushD_SE,		/* tlb_flushD_SE	*/
 
diff --git a/sys/arch/arm/arm/cpufunc_asm_armv7.S b/sys/arch/arm/arm/cpufunc_asm_armv7.S
index 6a6eeb16a9e..f1d43833819 100644
--- a/sys/arch/arm/arm/cpufunc_asm_armv7.S
+++ b/sys/arch/arm/arm/cpufunc_asm_armv7.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: cpufunc_asm_armv7.S,v 1.10 2016/04/25 04:46:56 jsg Exp $ */
+/* $OpenBSD: cpufunc_asm_armv7.S,v 1.11 2016/08/03 07:05:05 kettenis Exp $ */
 /*
  * Copyright (c) 2008 Dale Rahn <drahn@openbsd.org>
  *
@@ -45,7 +45,7 @@ ENTRY(armv7_setttb)
 	isb	sy
 
 	mcr	CP15_TTBR0(r0)		/* load new TTB */
-	mcr	CP15_TLBIALL(r0)	/* invalidate I+D TLBs */
+	mcr	CP15_TLBIALL(r0)	/* invalidate unified TLB */
 	dsb	sy
 	isb	sy
 
@@ -55,45 +55,27 @@ ENTRY(armv7_setttb)
  * TLB functions
  */
 ENTRY(armv7_tlb_flushID_SE)
-	mcr	CP15_DTLBIMVA		/* flush D tlb single entry */
-	mcr	CP15_ITLBIMVA		/* flush I tlb single entry */
+	mcr	CP15_TLBIMVA(r0)	/* flush unified tlb single entry */
 	mcr	CP15_BPIMVA		/* flush va from BP */
 	dsb	sy
 	isb	sy
 	mov	pc, lr
 
-ENTRY(armv7_tlb_flushI_SE)
-	mcr	CP15_ITLBIMVA		/* flush I tlb single entry */
-	mcr	CP15_BPIMVA		/* flush va from BP */
-	dsb	sy
-	isb	sy
-	mov	pc, lr
-
-/*
- * TLB functions
- */
 ENTRY(armv7_tlb_flushID)
-	mcr	CP15_TLBIALL(r0)	/* flush I+D tlb */
+	mcr	CP15_TLBIALL(r0)	/* flush unified tlb */
 	mcr	CP15_BPIALL		/* Flush BP cache */
 	dsb	sy
 	isb	sy
 	mov	pc, lr
 
-ENTRY(armv7_tlb_flushI)
-	mcr	CP15_ITLBIALL		/* flush I tlb */
-	mcr	CP15_BPIALL		/* Flush BP cache */
+ENTRY(armv7_tlb_flushD_SE)
+	mcr	CP15_TLBIMVA(r0)	/* flush unified tlb single entry */
 	dsb	sy
 	isb	sy
 	mov	pc, lr
 
 ENTRY(armv7_tlb_flushD)
-	mcr	CP15_DTLBIALL		/* flush D tlb */
-	dsb	sy
-	isb	sy
-	mov	pc, lr
-
-ENTRY(armv7_tlb_flushD_SE)
-	mcr	CP15_DTLBIMVA		/* flush D tlb single entry */
+	mcr	CP15_TLBIALL(r0)	/* flush unified tlb */
 	dsb	sy
 	isb	sy
 	mov	pc, lr
@@ -251,7 +233,7 @@ ENTRY(armv7_context_switch)
 	isb	sy
 
 	mcr	CP15_TTBR0(r0)		/* set the new TTB */
-	mcr	CP15_TLBIALL(r0)	/* and flush the I+D tlbs */
+	mcr	CP15_TLBIALL(r0)	/* and flush the unified tlb */
 	dsb	sy
 	isb	sy
 	mov	pc, lr