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parisc: map_pages(): cleanup page table initialization

PATCH New Mike Rapoport 1 participant 1 message Jan 12, 2020 PA-RISC architecture

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Mike Rapoport

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PATCH 1/1 parisc: map_pages(): cleanup page table initialization

From: Mike Rapoport <[email protected]>

The current code uses '#if PTRS_PER_PMD == 1' to distinguish 2 vs 3 levels, setup, it casts pgd to pgd to cope with page table folding and converts addresses of page table entries from physical to virtual and back for no good reason.

Simplify the accesses to the page table entries using proper unfolding of the upper layers and replacing '#if PTRS_PER_PMD' with explicit '#if CONFIG_PGTABLE_LEVELS == 3'

Signed-off-by Mike Rapoport <[email protected]>

---
Hi,

This patch is on top of the current parisc/for-next.
I've build-tested for generic-{32,64}_defconfig and was able to boot qemu-system-parisc up to rootfs mount.

 arch/parisc/mm/init.c | 50 +++++++++++--------------------------------
 1 file changed, 12 insertions(+), 38 deletions(-)
arch/parisc/mm/init.c +12 -38
index 354cf060b67f..5224fb38d766 100644
@@ -351,7 +351,6 @@ static void __init map_pages(unsigned long start_vaddr,
 			     unsigned long start_paddr, unsigned long size,
 			     pgprot_t pgprot, int force)
 {
-	pgd_t *pg_dir;
 	pmd_t *pmd;
 	pte_t *pg_table;
 	unsigned long end_paddr;

@@ -372,62 +371,37 @@ static void __init map_pages(unsigned long start_vaddr,
 
 	end_paddr = start_paddr + size;
 
-	pg_dir = pgd_offset_k(start_vaddr);
-
-#if PTRS_PER_PMD == 1
-	start_pmd = 0;
-#else
+	/* for 2-level configuration PTRS_PER_PMD is 0 so start_pmd will be 0 */
 	start_pmd = ((start_vaddr >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
-#endif
 	start_pte = ((start_vaddr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1));
 
 	address = start_paddr;
 	vaddr = start_vaddr;
 	while (address < end_paddr) {
-#if PTRS_PER_PMD == 1
-		pmd = (pmd_t *)__pa(pg_dir);
-#else
-		pmd = (pmd_t *)pgd_address(*pg_dir);
-
-		/*
-		 * pmd is physical at this point
-		 */
+		pgd_t *pgd = pgd_offset_k(vaddr);
+		p4d_t *p4d = p4d_offset(pgd, vaddr);
+		pud_t *pud = pud_offset(p4d, vaddr);
 
-		if (!pmd) {
+#if CONFIG_PGTABLE_LEVELS == 3
+		if (pud_none(*pud)) {
 			pmd = memblock_alloc(PAGE_SIZE << PMD_ORDER,
 					     PAGE_SIZE << PMD_ORDER);
 			if (!pmd)
 				panic("pmd allocation failed.\n");
-			pmd = (pmd_t *) __pa(pmd);
+			pud_populate(NULL, pud, pmd);
 		}
-
-		pud_populate(NULL, (pud_t *)pg_dir, __va(pmd));
 #endif
-		pg_dir++;
-
-		/* now change pmd to kernel virtual addresses */
 
-		pmd = (pmd_t *)__va(pmd) + start_pmd;
+		pmd = pmd_offset(pud, vaddr);
 		for (tmp1 = start_pmd; tmp1 < PTRS_PER_PMD; tmp1++, pmd++) {
-
-			/*
-			 * pg_table is physical at this point
-			 */
-
-			pg_table = (pte_t *)pmd_address(*pmd);
-			if (!pg_table) {
-				pg_table = memblock_alloc(PAGE_SIZE,
-							  PAGE_SIZE);
+			if (pmd_none(*pmd)) {
+				pg_table = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 				if (!pg_table)
 					panic("page table allocation failed\n");
-				pg_table = (pte_t *) __pa(pg_table);
+				pmd_populate_kernel(NULL, pmd, pg_table);
 			}
 
-			pmd_populate_kernel(NULL, pmd, __va(pg_table));
-
-			/* now change pg_table to kernel virtual addresses */
-
-			pg_table = (pte_t *) __va(pg_table) + start_pte;
+			pg_table = pte_offset_kernel(pmd, vaddr);
 			for (tmp2 = start_pte; tmp2 < PTRS_PER_PTE; tmp2++, pg_table++) {
 				pte_t pte;
 				pgprot_t prot;

base-commit: 9cf86a639ffdd9c38d510d35efcc15ed6dfb2efa

Signature · 1 line
2.24.0