[PATCH] arm64: Add support for 4level 4K page translations table

[asamson@xxxxxxxxxxxxxx (Azriel Samson)]

Add PUD translation for 4 level page tables.

Signed-off-by: Mansi Patel <mansip at codeaurora.org>
Signed-off-by: Azriel Samson <asamson at codeaurora.org>
---
This change targets the arm64_support branch of Pratush Anand's repository at:
https://github.com/pratyushanand/makedumpfile.git

 arch/arm64.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/arch/arm64.c b/arch/arm64.c
index 59825fa..62c76e3 100644
--- a/arch/arm64.c
+++ b/arch/arm64.c
@@ -35,15 +35,10 @@ typedef struct {
 	pud_t pud;
 } pmd_t;
 
-#define pud_offset(pgd, vaddr) 	((pud_t *)pgd)
-
 #define pgd_val(x)		((x).pgd)
 #define pud_val(x)		(pgd_val((x).pgd))
 #define pmd_val(x)		(pud_val((x).pud))
 
-#define PUD_SHIFT		PGDIR_SHIFT
-#define PUD_SIZE		(1UL << PUD_SHIFT)
-
 typedef struct {
 	unsigned long pte;
 } pte_t;
@@ -59,6 +54,10 @@ typedef struct {
 #define PMD_SIZE		(1UL << PMD_SHIFT)
 #define PMD_MASK		(~(PMD_SIZE - 1))
 #define PTRS_PER_PMD		PTRS_PER_PTE
+#define PUD_SHIFT		((PAGE_SHIFT - 3) * 3 + 3)
+#define PUD_SIZE		(1UL << PUD_SHIFT)
+#define PUD_MASK		(~(PUD_SIZE - 1))
+#define PTRS_PER_PUD		PTRS_PER_PTE
 
 #define PAGE_PRESENT		(1 << 0)
 #define SECTIONS_SIZE_BITS	30
@@ -95,6 +94,10 @@ typedef struct {
 #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))
 
+#define pud_index(vaddr)		(((vaddr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
+#define pgd_page_vaddr(pgd)		   (__va(pgd_val(pgd) & PHYS_MASK & (int32_t)PAGE_MASK))
+#define pud_offset(pgd, vaddr) ((pud_t *)pgd_page_vaddr((*pgd)) + pud_index(vaddr))
+
 /* kernel struct page size can be kernel version dependent, currently
  * keep it constant.
  */
@@ -244,7 +247,7 @@ vtop_arm64(unsigned long vaddr)
 {
 	unsigned long long paddr = NOT_PADDR;
 	pgd_t	*pgda, pgdv;
-	pud_t	pudv;
+	pud_t	*puda, pudv;
 	pmd_t	*pmda, pmdv;
 	pte_t 	*ptea, ptev;
 
@@ -259,7 +262,15 @@ vtop_arm64(unsigned long vaddr)
 		return NOT_PADDR;
 	}
 
-	pudv.pgd = pgdv;
+	if (pgtable_level <= 3) {
+		pudv.pgd = pgdv;
+	} else {
+		puda = pud_offset(&pgdv, vaddr);
+		if (!readmem(VADDR, (unsigned long long)puda, &pudv, sizeof(pudv))) {
+			ERRMSG("Can't read pud\n");
+			return NOT_PADDR;
+		}
+	}
 
 	pmda = pmd_offset(&pudv, vaddr);
 	if (!readmem(VADDR, (unsigned long long)pmda, &pmdv, sizeof(pmdv))) {
-- 
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