ARM64: 3 Level page support

index 06daf646e35d..643c21f8feb1 100644
@@ -23,7 +23,6 @@
 #include "../makedumpfile.h"
 #include "../print_info.h"
 
-#if CONFIG_ARM64_PGTABLE_LEVELS == 2
 typedef struct {
 	unsigned long pgd;
 } pgd_t;

@@ -45,8 +44,6 @@ typedef struct {
 #define PUD_SHIFT		PGDIR_SHIFT
 #define PUD_SIZE		(1UL << PUD_SHIFT)
 
-#endif
-
 typedef struct {
 	unsigned long pte;
 } pte_t;

@@ -96,6 +93,41 @@ typedef struct {
 #define MODULES_END			PAGE_OFFSET
 #define MODULES_VADDR			(MODULES_END - 0x4000000)
 
+static int pgtable_level;
+static int va_bits;
+static int page_shift;
+
+int
+get_pgtable_level_arm64(void)
+{
+	return pgtable_level;
+}
+
+int
+get_va_bits_arm64(void)
+{
+	return va_bits;
+}
+
+int
+get_page_shift_arm64(void)
+{
+	return page_shift;
+}
+
+static int calculate_plat_config(void)
+{
+	/*
+	 * TODO: Keep it fixed for page level 2, size 64K and VA bits as
+	 * 42, as of now. Will calculate them from symbol address values
+	 * latter.
+	 */
+	pgtable_level = 2;
+	va_bits = 42;
+	page_shift = 16;
+
+	return TRUE;
+}
 
 static int
 is_vtop_from_page_table_arm64(unsigned long vaddr)

@@ -114,6 +146,12 @@ get_phys_base_arm64(void)
 	unsigned long phys_base = ULONG_MAX;
 	unsigned long long phys_start;
 	int i;
+
+	if (!calculate_plat_config()) {
+		ERRMSG("Can't determine platform config values\n");
+		return FALSE;
+	}
+
 	/*
 	 * We resolve phys_base from PT_LOAD segments. LMA contains physical
 	 * address of the segment, and we use the lowest start as

index e333ae8a37a2..abe6a9897095 100644
@@ -503,28 +503,10 @@ do { \
 #define PMASK			(0x7ffffffffffff000UL)
 
 #ifdef __aarch64__
-#define CONFIG_ARM64_PGTABLE_LEVELS	2
-#define CONFIG_ARM64_VA_BITS		42
-#define CONFIG_ARM64_64K_PAGES		1
-
-/* Currently we only suport following defines based on above
- * config definitions.
- * TODOs: We need to find a way to get above defines dynamically and
- * then to support following definitions based on that
- */
-
-#if CONFIG_ARM64_PGTABLE_LEVELS == 2
-#define ARM64_PGTABLE_LEVELS	2
-#endif
-
-#if CONFIG_ARM64_VA_BITS == 42
-#define VA_BITS			42
-#endif
-
-#ifdef CONFIG_ARM64_64K_PAGES
-#define PAGE_SHIFT		16
-#endif
-
+int get_va_bits_arm64(void);
+#define ARM64_PGTABLE_LEVELS	get_pgtable_level_arm64()
+#define VA_BITS			get_va_bits_arm64()
+#define PAGE_SHIFT		get_page_shift_arm64()
 #define KVBASE_MASK		(0xffffffffffffffffUL << (VA_BITS - 1))
 #define KVBASE			(SYMBOL(_stext) & KVBASE_MASK)
 #endif /* aarch64 */

index 4d50012529c3..a94a4ba16dd5 100644
@@ -199,7 +199,8 @@ get_machdep_info_arm64(void)
 {
 	info->max_physmem_bits = PHYS_MASK_SHIFT;
 	info->section_size_bits = SECTIONS_SIZE_BITS;
-	info->page_offset = KVBASE;
+	info->page_offset = SYMBOL(_stext)
+		& (0xffffffffffffffffUL << (VA_BITS - 1));
 	info->vmalloc_start = 0xffffffffffffffffUL << VA_BITS;
 	info->vmalloc_end = PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - 0x10000;
 	info->vmemmap_start = VMALLOC_END + 0x10000;

index abe6a9897095..c42fc8142663 100644
@@ -507,8 +507,7 @@ int get_va_bits_arm64(void);
 #define ARM64_PGTABLE_LEVELS	get_pgtable_level_arm64()
 #define VA_BITS			get_va_bits_arm64()
 #define PAGE_SHIFT		get_page_shift_arm64()
-#define KVBASE_MASK		(0xffffffffffffffffUL << (VA_BITS - 1))
-#define KVBASE			(SYMBOL(_stext) & KVBASE_MASK)
+#define KVBASE			VMALLOC_START
 #endif /* aarch64 */
 
 #ifdef __arm__

index 643c21f8feb1..4d50012529c3 100644
@@ -115,16 +115,36 @@ get_page_shift_arm64(void)
 	return page_shift;
 }
 
+#define PAGE_OFFSET_39 (0xffffffffffffffffUL << 39)
+#define PAGE_OFFSET_42 (0xffffffffffffffffUL << 42)
 static int calculate_plat_config(void)
 {
-	/*
-	 * TODO: Keep it fixed for page level 2, size 64K and VA bits as
-	 * 42, as of now. Will calculate them from symbol address values
-	 * latter.
+	unsigned long long stext;
+
+	/* Currently we assume that there are only two possible
+	 * configuration supported by kernel.
+	 * 1) Page Table Level:2, Page Size 64K and VA Bits 42
+	 * 1) Page Table Level:3, Page Size 4K and VA Bits 39
+	 * Ideally, we should have some mechanism to decide these values
+	 * from kernel symbols, but we have limited symbols in vmcore,
+	 * and we can not do much. So until some one comes with a better
+	 * way, we use following.
 	 */
-	pgtable_level = 2;
-	va_bits = 42;
-	page_shift = 16;
+	stext = SYMBOL(_stext);
+
+	/* condition for minimum VA bits must be checked first and so on */
+	if ((stext & PAGE_OFFSET_39) == PAGE_OFFSET_39) {
+		pgtable_level = 3;
+		va_bits = 39;
+		page_shift = 12;
+	} else if ((stext & PAGE_OFFSET_42) == PAGE_OFFSET_42) {
+		pgtable_level = 2;
+		va_bits = 42;
+		page_shift = 16;
+	} else {
+		ERRMSG("Kernel Configuration not supported\n");
+		return FALSE;
+	}
 
 	return TRUE;
 }

index a94a4ba16dd5..ab20389fa673 100644
@@ -36,7 +36,7 @@ typedef struct {
 } pmd_t;
 
 #define pud_offset(pgd, vaddr) 	((pud_t *)pgd)
-#define pmd_offset(pud, vaddr) 	((pmd_t *)pud)
+
 #define pgd_val(x)		((x).pgd)
 #define pud_val(x)		(pgd_val((x).pgd))
 #define pmd_val(x)		(pud_val((x).pud))

@@ -68,6 +68,11 @@ typedef struct {
 */
 #define PHYS_MASK_SHIFT		48
 #define PHYS_MASK		((1UL << PHYS_MASK_SHIFT) - 1)
+/*
+ * Remove the highest order bits that are not a part of the
+ * physical address in a section
+ */
+#define PMD_SECTION_MASK        ((1UL << 40) - 1)
 
 #define PMD_TYPE_MASK		3
 #define PMD_TYPE_SECT		1

@@ -83,10 +88,18 @@ typedef struct {
 #define pmd_page_vaddr(pmd)		(__va(pmd_val(pmd) & PHYS_MASK & (int32_t)PAGE_MASK))
 #define pte_offset(dir, vaddr) 		((pte_t*)pmd_page_vaddr((*dir)) + pte_index(vaddr))
 
+
+#define pmd_offset_pgtbl_lvl_2(pud, vaddr) ((pmd_t *)pud)
+
+#define pmd_index(vaddr)		(((vaddr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
+#define pud_page_vaddr(pud)		(__va(pud_val(pud) & PHYS_MASK & (int32_t)PAGE_MASK))
+#define pmd_offset_pgtbl_lvl_3(pud, vaddr) ((pmd_t *)pud_page_vaddr((*pud)) + pmd_index(vaddr))
+
 /* kernel struct page size can be kernel version dependent, currently
  * keep it constant.
  */
-#define KERN_STRUCT_PAGE_SIZE		64
+#define KERN_STRUCT_PAGE_SIZE		get_structure_size("page", DWARF_INFO_GET_STRUCT_SIZE)
+
 #define ALIGN(x, a) 			(((x) + (a) - 1) & ~((a) - 1))
 #define PFN_DOWN(x)			((x) >> PAGE_SHIFT)
 #define VMEMMAP_SIZE			ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * KERN_STRUCT_PAGE_SIZE, PUD_SIZE)

@@ -97,6 +110,15 @@ static int pgtable_level;
 static int va_bits;
 static int page_shift;
 
+pmd_t *
+pmd_offset(pud_t *pud, unsigned long vaddr)
+{
+	if (pgtable_level == 2) {
+		return pmd_offset_pgtbl_lvl_2(pud, vaddr);
+	} else {
+		return pmd_offset_pgtbl_lvl_3(pud, vaddr);
+	}
+}
 int
 get_pgtable_level_arm64(void)
 {

@@ -256,7 +278,7 @@ vtop_arm64(unsigned long vaddr)
 {
 	unsigned long long paddr = NOT_PADDR;
 	pgd_t	*pgda, pgdv;
-	pud_t	*puda;
+	pud_t	*puda, pudv;
 	pmd_t	*pmda, pmdv;
 	pte_t 	*ptea, ptev;
 

@@ -271,8 +293,9 @@ vtop_arm64(unsigned long vaddr)
 		return NOT_PADDR;
 	}
 
-	puda = pud_offset(pgda, vaddr);
-	pmda = pmd_offset(puda, vaddr);
+	pudv.pgd = pgdv;
+
+	pmda = pmd_offset(&pudv, vaddr);
 	if (!readmem(VADDR, (unsigned long long)pmda, &pmdv, sizeof(pmdv))) {
 		ERRMSG("Can't read pmd\n");
 		return NOT_PADDR;

@@ -298,7 +321,8 @@ vtop_arm64(unsigned long vaddr)
 		break;
 	case PMD_TYPE_SECT:
 		/* 1GB section */
-		paddr = (pmd_val(pmdv) & PMD_MASK) + (vaddr & (PMD_SIZE - 1));
+		paddr = (pmd_val(pmdv) & (PMD_MASK & PMD_SECTION_MASK))
+					+ (vaddr & (PMD_SIZE - 1));
 		break;
 	}