From 1b6ba46b7efa31055eb993a6f2c6bbcb8b35b001 Mon Sep 17 00:00:00 2001
From: Catalin Marinas
Date: Tue, 22 Nov 2011 17:30:29 +0000
Subject: ARM: LPAE: MMU setup for the 3-level page table format

This patch adds the MMU initialisation for the LPAE page table format.
The swapper_pg_dir size with LPAE is 5 rather than 4 pages. A new
proc-v7-3level.S file contains the TTB initialisation, context switch
and PTE setting code with the LPAE. The TTBRx split is based on the
PAGE_OFFSET with TTBR1 used for the kernel mappings. The 36-bit mappings
(supersections) and a few other memory types in mmu.c are conditionally
compiled.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm/kernel/head.S | 45 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

(limited to 'arch/arm/kernel')

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 54eb94aff6cd..c8e797baaf55 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -39,8 +39,14 @@
 #error KERNEL_RAM_VADDR must start at 0xXXXX8000
 #endif
 
+#ifdef CONFIG_ARM_LPAE
+	/* LPAE requires an additional page for the PGD */
+#define PG_DIR_SIZE	0x5000
+#define PMD_ORDER	3
+#else
 #define PG_DIR_SIZE	0x4000
 #define PMD_ORDER	2
+#endif
 
 	.globl	swapper_pg_dir
 	.equ	swapper_pg_dir, KERNEL_RAM_VADDR - PG_DIR_SIZE
@@ -164,6 +170,25 @@ __create_page_tables:
 	teq	r0, r6
 	bne	1b
 
+#ifdef CONFIG_ARM_LPAE
+	/*
+	 * Build the PGD table (first level) to point to the PMD table. A PGD
+	 * entry is 64-bit wide.
+	 */
+	mov	r0, r4
+	add	r3, r4, #0x1000			@ first PMD table address
+	orr	r3, r3, #3			@ PGD block type
+	mov	r6, #4				@ PTRS_PER_PGD
+	mov	r7, #1 << (55 - 32)		@ L_PGD_SWAPPER
+1:	str	r3, [r0], #4			@ set bottom PGD entry bits
+	str	r7, [r0], #4			@ set top PGD entry bits
+	add	r3, r3, #0x1000			@ next PMD table
+	subs	r6, r6, #1
+	bne	1b
+
+	add	r4, r4, #0x1000			@ point to the PMD tables
+#endif
+
 	ldr	r7, [r10, #PROCINFO_MM_MMUFLAGS] @ mm_mmuflags
 
 	/*
@@ -219,8 +244,8 @@ __create_page_tables:
 #endif
 
 	/*
-	 * Then map boot params address in r2 or
-	 * the first 1MB of ram if boot params address is not specified.
+	 * Then map boot params address in r2 or the first 1MB (2MB with LPAE)
+	 * of ram if boot params address is not specified.
 	 */
 	mov	r0, r2, lsr #SECTION_SHIFT
 	movs	r0, r0, lsl #SECTION_SHIFT
@@ -251,7 +276,15 @@ __create_page_tables:
 	mov	r3, r7, lsr #SECTION_SHIFT
 	ldr	r7, [r10, #PROCINFO_IO_MMUFLAGS] @ io_mmuflags
 	orr	r3, r7, r3, lsl #SECTION_SHIFT
+#ifdef CONFIG_ARM_LPAE
+	mov	r7, #1 << (54 - 32)		@ XN
+#else
+	orr	r3, r3, #PMD_SECT_XN
+#endif
 1:	str	r3, [r0], #4
+#ifdef CONFIG_ARM_LPAE
+	str	r7, [r0], #4
+#endif
 	add	r3, r3, #1 << SECTION_SHIFT
 	cmp	r0, r6
 	blo	1b
@@ -282,6 +315,9 @@ __create_page_tables:
 	add	r0, r4, #0xd8000000 >> (SECTION_SHIFT - PMD_ORDER)
 	str	r3, [r0]
 #endif
+#endif
+#ifdef CONFIG_ARM_LPAE
+	sub	r4, r4, #0x1000		@ point to the PGD table
 #endif
 	mov	pc, lr
 ENDPROC(__create_page_tables)
@@ -374,12 +410,17 @@ __enable_mmu:
 #ifdef CONFIG_CPU_ICACHE_DISABLE
 	bic	r0, r0, #CR_I
 #endif
+#ifdef CONFIG_ARM_LPAE
+	mov	r5, #0
+	mcrr	p15, 0, r4, r5, c2		@ load TTBR0
+#else
 	mov	r5, #(domain_val(DOMAIN_USER, DOMAIN_MANAGER) | \
 		      domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
 		      domain_val(DOMAIN_TABLE, DOMAIN_MANAGER) | \
 		      domain_val(DOMAIN_IO, DOMAIN_CLIENT))
 	mcr	p15, 0, r5, c3, c0, 0		@ load domain access register
 	mcr	p15, 0, r4, c2, c0, 0		@ load page table pointer
+#endif
 	b	__turn_mmu_on
 ENDPROC(__enable_mmu)
 
-- 
cgit v1.2.3-55-g7522