[RFC 1/2] mm/vmemmap: Enable vmem_altmap based base page mapping for vmemmap

[Anshuman Khandual]

vmemmap_populate_basepages() is used for vmemmap mapping across platforms.
On arm64 it is used for ARM64_16K_PAGES and ARM64_64K_PAGES configs. When
applicable enable it's allocation from device memory range through struct
vmem_altpamp. Individual archs should enable this when appropriate. Hence
keep it disabled to continue with the existing semantics.

Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 arch/arm64/mm/mmu.c      |  2 +-
 arch/ia64/mm/discontig.c |  2 +-
 arch/x86/mm/init_64.c    |  4 ++--
 include/linux/mm.h       |  5 +++--
 mm/sparse-vmemmap.c      | 14 ++++++++++----
 5 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 4b25b7544763..2859aa89cc4a 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -921,7 +921,7 @@ remove_pagetable(unsigned long start, unsigned long end,
 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 		struct vmem_altmap *altmap)
 {
-	return vmemmap_populate_basepages(start, end, node);
+	return vmemmap_populate_basepages(start, end, node, NULL);
 }
 #else	/* !ARM64_SWAPPER_USES_SECTION_MAPS */
 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index 05490dd073e6..faefd7ec991f 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -660,7 +660,7 @@ void arch_refresh_nodedata(int update_node, pg_data_t *update_pgdat)
 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 		struct vmem_altmap *altmap)
 {
-	return vmemmap_populate_basepages(start, end, node);
+	return vmemmap_populate_basepages(start, end, node, NULL);
 }
 
 void vmemmap_free(unsigned long start, unsigned long end,
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index bccff68e3267..e7e05d1b8bcf 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1450,7 +1450,7 @@ static int __meminit vmemmap_populate_hugepages(unsigned long start,
 			vmemmap_verify((pte_t *)pmd, node, addr, next);
 			continue;
 		}
-		if (vmemmap_populate_basepages(addr, next, node))
+		if (vmemmap_populate_basepages(addr, next, node, NULL))
 			return -ENOMEM;
 	}
 	return 0;
@@ -1468,7 +1468,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 				__func__);
 		err = -ENOMEM;
 	} else
-		err = vmemmap_populate_basepages(start, end, node);
+		err = vmemmap_populate_basepages(start, end, node, NULL);
 	if (!err)
 		sync_global_pgds(start, end - 1);
 	return err;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 76769749b5a5..a62e9ff24af3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2672,14 +2672,15 @@ pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
 p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
 pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
 pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
-pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
+pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
+					struct vmem_altmap *altmap);
 void *vmemmap_alloc_block(unsigned long size, int node);
 struct vmem_altmap;
 void *vmemmap_alloc_block_buf(unsigned long size, int node);
 void *altmap_alloc_block_buf(unsigned long size, struct vmem_altmap *altmap);
 void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
 int vmemmap_populate_basepages(unsigned long start, unsigned long end,
-			       int node);
+			       int node, struct vmem_altmap *altmap);
 int vmemmap_populate(unsigned long start, unsigned long end, int node,
 		struct vmem_altmap *altmap);
 void vmemmap_populate_print_last(void);
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 7fec05796796..81a0960b5cd4 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -140,12 +140,18 @@ void __meminit vmemmap_verify(pte_t *pte, int node,
 			start, end - 1);
 }
 
-pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
+pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
+				struct vmem_altmap *altmap)
 {
 	pte_t *pte = pte_offset_kernel(pmd, addr);
 	if (pte_none(*pte)) {
 		pte_t entry;
-		void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node);
+		void *p;
+
+		if (altmap)
+			p = altmap_alloc_block_buf(PAGE_SIZE, altmap);
+		else
+			p = vmemmap_alloc_block_buf(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
 		entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
@@ -214,7 +220,7 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
 }
 
 int __meminit vmemmap_populate_basepages(unsigned long start,
-					 unsigned long end, int node)
+			unsigned long end, int node, struct vmem_altmap *altmap)
 {
 	unsigned long addr = start;
 	pgd_t *pgd;
@@ -236,7 +242,7 @@ int __meminit vmemmap_populate_basepages(unsigned long start,
 		pmd = vmemmap_pmd_populate(pud, addr, node);
 		if (!pmd)
 			return -ENOMEM;
-		pte = vmemmap_pte_populate(pmd, addr, node);
+		pte = vmemmap_pte_populate(pmd, addr, node, altmap);
 		if (!pte)
 			return -ENOMEM;
 		vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
-- 
2.20.1