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>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index dc8c550..1935311 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -150,6 +150,7 @@ static int __init early_nowrite(char *__unused)
 }
 early_param("nowb", early_nowrite);
 
+#ifndef CONFIG_ARM_LPAE
 static int __init early_ecc(char *p)
 {
 	if (memcmp(p, "on", 2) == 0)
@@ -159,6 +160,7 @@ static int __init early_ecc(char *p)
 	return 0;
 }
 early_param("ecc", early_ecc);
+#endif
 
 static int __init noalign_setup(char *__unused)
 {
@@ -228,10 +230,12 @@ static struct mem_type mem_types[] = {
 		.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
 		.domain    = DOMAIN_KERNEL,
 	},
+#ifndef CONFIG_ARM_LPAE
 	[MT_MINICLEAN] = {
 		.prot_sect = PMD_TYPE_SECT | PMD_SECT_XN | PMD_SECT_MINICACHE,
 		.domain    = DOMAIN_KERNEL,
 	},
+#endif
 	[MT_LOW_VECTORS] = {
 		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
 				L_PTE_RDONLY,
@@ -429,6 +433,7 @@ static void __init build_mem_type_table(void)
 	 * ARMv6 and above have extended page tables.
 	 */
 	if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
+#ifndef CONFIG_ARM_LPAE
 		/*
 		 * Mark cache clean areas and XIP ROM read only
 		 * from SVC mode and no access from userspace.
@@ -436,6 +441,7 @@ static void __init build_mem_type_table(void)
 		mem_types[MT_ROM].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 		mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
 		mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
+#endif
 
 		if (is_smp()) {
 			/*
@@ -474,6 +480,18 @@ static void __init build_mem_type_table(void)
 		mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_BUFFERABLE;
 	}
 
+#ifdef CONFIG_ARM_LPAE
+	/*
+	 * Do not generate access flag faults for the kernel mappings.
+	 */
+	for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
+		mem_types[i].prot_pte |= PTE_EXT_AF;
+		mem_types[i].prot_sect |= PMD_SECT_AF;
+	}
+	kern_pgprot |= PTE_EXT_AF;
+	vecs_pgprot |= PTE_EXT_AF;
+#endif
+
 	for (i = 0; i < 16; i++) {
 		unsigned long v = pgprot_val(protection_map[i]);
 		protection_map[i] = __pgprot(v | user_pgprot);
@@ -572,8 +590,10 @@ static void __init alloc_init_section(pud_t *pud, unsigned long addr,
 	if (((addr | end | phys) & ~SECTION_MASK) == 0) {
 		pmd_t *p = pmd;
 
+#ifndef CONFIG_ARM_LPAE
 		if (addr & SECTION_SIZE)
 			pmd++;
+#endif
 
 		do {
 			*pmd = __pmd(phys | type->prot_sect);
@@ -603,6 +623,7 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 	} while (pud++, addr = next, addr != end);
 }
 
+#ifndef CONFIG_ARM_LPAE
 static void __init create_36bit_mapping(struct map_desc *md,
 					const struct mem_type *type)
 {
@@ -662,6 +683,7 @@ static void __init create_36bit_mapping(struct map_desc *md,
 		pgd += SUPERSECTION_SIZE >> PGDIR_SHIFT;
 	} while (addr != end);
 }
+#endif	/* !CONFIG_ARM_LPAE */
 
 /*
  * Create the page directory entries and any necessary
@@ -693,6 +715,7 @@ static void __init create_mapping(struct map_desc *md)
 
 	type = &mem_types[md->type];
 
+#ifndef CONFIG_ARM_LPAE
 	/*
 	 * Catch 36-bit addresses
 	 */
@@ -700,6 +723,7 @@ static void __init create_mapping(struct map_desc *md)
 		create_36bit_mapping(md, type);
 		return;
 	}
+#endif
 
 	addr = md->virtual & PAGE_MASK;
 	phys = __pfn_to_phys(md->pfn);
@@ -897,7 +921,13 @@ static inline void prepare_page_table(void)
 		pmd_clear(pmd_off_k(addr));
 }
 
+#ifdef CONFIG_ARM_LPAE
+/* the first page is reserved for pgd */
+#define SWAPPER_PG_DIR_SIZE	(PAGE_SIZE + \
+				 PTRS_PER_PGD * PTRS_PER_PMD * sizeof(pmd_t))
+#else
 #define SWAPPER_PG_DIR_SIZE	(PTRS_PER_PGD * sizeof(pgd_t))
+#endif
 
 /*
  * Reserve the special regions of memory