[PATCH v9 00/12] huge vmalloc mappings

[PATCH v9 00/12] huge vmalloc mappings

[Nicholas Piggin]

Hi Andrew,

A couple of things Rick noticed, he's working on huge module mappings
to help iTLB pressure and seems to think this series will be useful
infrastructure for his work.

I think it finally should be just about ready.

Thanks,
Nick

Since v8:
- Fixed nommu compile.
- Added Kconfig option help text
- Added VM_NOHUGE which should help archs implement it [suggested by Rick]

Since v7:
- Rebase, added some acks, compile fix
- Removed "order=" from vmallocinfo, it's a bit confusing (nr_pages
  is in small page size for compatibility).
- Added arch_vmap_pmd_supported() test before starting to allocate
  the large page, rather than only testing it when doing the map, to
  avoid unsupported configs trying to allocate huge pages for no
  reason.

Since v6:
- Fixed a false positive warning introduced in patch 2, found by
  kbuild test robot.

Since v5:
- Split arch changes out better and make the constant folding work
- Avoid most of the 80 column wrap, fix a reference to lib/ioremap.c
- Fix compile error on some archs

Since v4:
- Fixed an off-by-page-order bug in v4
- Several minor cleanups.
- Added page order to /proc/vmallocinfo
- Added hugepage to alloc_large_system_hage output.
- Made an architecture config option, powerpc only for now.

Since v3:
- Fixed an off-by-one bug in a loop
- Fix !CONFIG_HAVE_ARCH_HUGE_VMAP build fail
- Hopefully this time fix the arm64 vmap stack bug, thanks Jonathan
  Cameron for debugging the cause of this (hopefully).

Since v2:
- Rebased on vmalloc cleanups, split series into simpler pieces.
- Fixed several compile errors and warnings
- Keep the page array and accounting in small page units because
  struct vm_struct is an interface (this should fix x86 vmap stack debug
  assert). [Thanks Zefan]

Nicholas Piggin (12):
  mm/vmalloc: fix vmalloc_to_page for huge vmap mappings
  mm: apply_to_pte_range warn and fail if a large pte is encountered
  mm/vmalloc: rename vmap_*_range vmap_pages_*_range
  mm/ioremap: rename ioremap_*_range to vmap_*_range
  mm: HUGE_VMAP arch support cleanup
  powerpc: inline huge vmap supported functions
  arm64: inline huge vmap supported functions
  x86: inline huge vmap supported functions
  mm: Move vmap_range from mm/ioremap.c to mm/vmalloc.c
  mm/vmalloc: add vmap_range_noflush variant
  mm/vmalloc: Hugepage vmalloc mappings
  powerpc/64s/radix: Enable huge vmalloc mappings

 .../admin-guide/kernel-parameters.txt         |   2 +
 arch/Kconfig                                  |  10 +
 arch/arm64/include/asm/vmalloc.h              |  25 +
 arch/arm64/mm/mmu.c                           |  26 -
 arch/powerpc/Kconfig                          |   1 +
 arch/powerpc/include/asm/vmalloc.h            |  21 +
 arch/powerpc/kernel/module.c                  |  13 +-
 arch/powerpc/mm/book3s64/radix_pgtable.c      |  21 -
 arch/x86/include/asm/vmalloc.h                |  23 +
 arch/x86/mm/ioremap.c                         |  19 -
 arch/x86/mm/pgtable.c                         |  13 -
 include/linux/io.h                            |   9 -
 include/linux/vmalloc.h                       |  27 ++
 init/main.c                                   |   1 -
 mm/ioremap.c                                  | 225 +--------
 mm/memory.c                                   |  66 ++-
 mm/page_alloc.c                               |   5 +-
 mm/vmalloc.c                                  | 454 +++++++++++++++---
 18 files changed, 564 insertions(+), 397 deletions(-)

-- 
2.23.0

[PATCH v9 01/12] mm/vmalloc: fix vmalloc_to_page for huge vmap mappings

[Nicholas Piggin]

vmalloc_to_page returns NULL for addresses mapped by larger pages[*].
Whether or not a vmap is huge depends on the architecture details,
alignments, boot options, etc., which the caller can not be expected
to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page.

This change teaches vmalloc_to_page about larger pages, and returns
the struct page that corresponds to the offset within the large page.
This makes the API agnostic to mapping implementation details.

[*] As explained by commit 029c54b095995 ("mm/vmalloc.c: huge-vmap:
    fail gracefully on unexpected huge vmap mappings")

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 mm/vmalloc.c | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 6ae491a8b210..f85124e88bdb 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -34,7 +34,7 @@
 #include <linux/bitops.h>
 #include <linux/rbtree_augmented.h>
 #include <linux/overflow.h>
-
+#include <linux/pgtable.h>
 #include <linux/uaccess.h>
 #include <asm/tlbflush.h>
 #include <asm/shmparam.h>
@@ -343,7 +343,9 @@ int is_vmalloc_or_module_addr(const void *x)
 }
 
 /*
- * Walk a vmap address to the struct page it maps.
+ * Walk a vmap address to the struct page it maps. Huge vmap mappings will
+ * return the tail page that corresponds to the base page address, which
+ * matches small vmap mappings.
  */
 struct page *vmalloc_to_page(const void *vmalloc_addr)
 {
@@ -363,25 +365,33 @@ struct page *vmalloc_to_page(const void *vmalloc_addr)
 
 	if (pgd_none(*pgd))
 		return NULL;
+	if (WARN_ON_ONCE(pgd_leaf(*pgd)))
+		return NULL; /* XXX: no allowance for huge pgd */
+	if (WARN_ON_ONCE(pgd_bad(*pgd)))
+		return NULL;
+
 	p4d = p4d_offset(pgd, addr);
 	if (p4d_none(*p4d))
 		return NULL;
-	pud = pud_offset(p4d, addr);
+	if (p4d_leaf(*p4d))
+		return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT);
+	if (WARN_ON_ONCE(p4d_bad(*p4d)))
+		return NULL;
 
-	/*
-	 * Don't dereference bad PUD or PMD (below) entries. This will also
-	 * identify huge mappings, which we may encounter on architectures
-	 * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be
-	 * identified as vmalloc addresses by is_vmalloc_addr(), but are
-	 * not [unambiguously] associated with a struct page, so there is
-	 * no correct value to return for them.
-	 */
-	WARN_ON_ONCE(pud_bad(*pud));
-	if (pud_none(*pud) || pud_bad(*pud))
+	pud = pud_offset(p4d, addr);
+	if (pud_none(*pud))
+		return NULL;
+	if (pud_leaf(*pud))
+		return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
+	if (WARN_ON_ONCE(pud_bad(*pud)))
 		return NULL;
+
 	pmd = pmd_offset(pud, addr);
-	WARN_ON_ONCE(pmd_bad(*pmd));
-	if (pmd_none(*pmd) || pmd_bad(*pmd))
+	if (pmd_none(*pmd))
+		return NULL;
+	if (pmd_leaf(*pmd))
+		return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+	if (WARN_ON_ONCE(pmd_bad(*pmd)))
 		return NULL;
 
 	ptep = pte_offset_map(pmd, addr);
@@ -389,6 +399,7 @@ struct page *vmalloc_to_page(const void *vmalloc_addr)
 	if (pte_present(pte))
 		page = pte_page(pte);
 	pte_unmap(ptep);
+
 	return page;
 }
 EXPORT_SYMBOL(vmalloc_to_page);
-- 
2.23.0

[PATCH v9 02/12] mm: apply_to_pte_range warn and fail if a large pte is encountered

[Nicholas Piggin]

apply_to_pte_range might mistake a large pte for bad, or treat it as a
page table, resulting in a crash or corruption. Add a test to warn and
return error if large entries are found.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 mm/memory.c | 66 +++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 49 insertions(+), 17 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index c48f8df6e502..3d0f0bc5d573 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2429,13 +2429,21 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
 	}
 	do {
 		next = pmd_addr_end(addr, end);
-		if (create || !pmd_none_or_clear_bad(pmd)) {
-			err = apply_to_pte_range(mm, pmd, addr, next, fn, data,
-						 create, mask);
-			if (err)
-				break;
+		if (pmd_none(*pmd) && !create)
+			continue;
+		if (WARN_ON_ONCE(pmd_leaf(*pmd)))
+			return -EINVAL;
+		if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) {
+			if (!create)
+				continue;
+			pmd_clear_bad(pmd);
 		}
+		err = apply_to_pte_range(mm, pmd, addr, next,
+					 fn, data, create, mask);
+		if (err)
+			break;
 	} while (pmd++, addr = next, addr != end);
+
 	return err;
 }
 
@@ -2457,13 +2465,21 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
 	}
 	do {
 		next = pud_addr_end(addr, end);
-		if (create || !pud_none_or_clear_bad(pud)) {
-			err = apply_to_pmd_range(mm, pud, addr, next, fn, data,
-						 create, mask);
-			if (err)
-				break;
+		if (pud_none(*pud) && !create)
+			continue;
+		if (WARN_ON_ONCE(pud_leaf(*pud)))
+			return -EINVAL;
+		if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) {
+			if (!create)
+				continue;
+			pud_clear_bad(pud);
 		}
+		err = apply_to_pmd_range(mm, pud, addr, next,
+					 fn, data, create, mask);
+		if (err)
+			break;
 	} while (pud++, addr = next, addr != end);
+
 	return err;
 }
 
@@ -2485,13 +2501,21 @@ static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
 	}
 	do {
 		next = p4d_addr_end(addr, end);
-		if (create || !p4d_none_or_clear_bad(p4d)) {
-			err = apply_to_pud_range(mm, p4d, addr, next, fn, data,
-						 create, mask);
-			if (err)
-				break;
+		if (p4d_none(*p4d) && !create)
+			continue;
+		if (WARN_ON_ONCE(p4d_leaf(*p4d)))
+			return -EINVAL;
+		if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) {
+			if (!create)
+				continue;
+			p4d_clear_bad(p4d);
 		}
+		err = apply_to_pud_range(mm, p4d, addr, next,
+					 fn, data, create, mask);
+		if (err)
+			break;
 	} while (p4d++, addr = next, addr != end);
+
 	return err;
 }
 
@@ -2511,9 +2535,17 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
 	pgd = pgd_offset(mm, addr);
 	do {
 		next = pgd_addr_end(addr, end);
-		if (!create && pgd_none_or_clear_bad(pgd))
+		if (pgd_none(*pgd) && !create)
 			continue;
-		err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask);
+		if (WARN_ON_ONCE(pgd_leaf(*pgd)))
+			return -EINVAL;
+		if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) {
+			if (!create)
+				continue;
+			pgd_clear_bad(pgd);
+		}
+		err = apply_to_p4d_range(mm, pgd, addr, next,
+					 fn, data, create, &mask);
 		if (err)
 			break;
 	} while (pgd++, addr = next, addr != end);
-- 
2.23.0

[PATCH v9 03/12] mm/vmalloc: rename vmap_*_range vmap_pages_*_range

[Nicholas Piggin]

The vmalloc mapper operates on a struct page * array rather than a
linear physical address, re-name it to make this distinction clear.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 mm/vmalloc.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index f85124e88bdb..42326dbffaf0 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -189,7 +189,7 @@ void unmap_kernel_range_noflush(unsigned long start, unsigned long size)
 		arch_sync_kernel_mappings(start, end);
 }
 
-static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
+static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
 		unsigned long end, pgprot_t prot, struct page **pages, int *nr,
 		pgtbl_mod_mask *mask)
 {
@@ -217,7 +217,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 
-static int vmap_pmd_range(pud_t *pud, unsigned long addr,
+static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr,
 		unsigned long end, pgprot_t prot, struct page **pages, int *nr,
 		pgtbl_mod_mask *mask)
 {
@@ -229,13 +229,13 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr,
 		return -ENOMEM;
 	do {
 		next = pmd_addr_end(addr, end);
-		if (vmap_pte_range(pmd, addr, next, prot, pages, nr, mask))
+		if (vmap_pages_pte_range(pmd, addr, next, prot, pages, nr, mask))
 			return -ENOMEM;
 	} while (pmd++, addr = next, addr != end);
 	return 0;
 }
 
-static int vmap_pud_range(p4d_t *p4d, unsigned long addr,
+static int vmap_pages_pud_range(p4d_t *p4d, unsigned long addr,
 		unsigned long end, pgprot_t prot, struct page **pages, int *nr,
 		pgtbl_mod_mask *mask)
 {
@@ -247,13 +247,13 @@ static int vmap_pud_range(p4d_t *p4d, unsigned long addr,
 		return -ENOMEM;
 	do {
 		next = pud_addr_end(addr, end);
-		if (vmap_pmd_range(pud, addr, next, prot, pages, nr, mask))
+		if (vmap_pages_pmd_range(pud, addr, next, prot, pages, nr, mask))
 			return -ENOMEM;
 	} while (pud++, addr = next, addr != end);
 	return 0;
 }
 
-static int vmap_p4d_range(pgd_t *pgd, unsigned long addr,
+static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr,
 		unsigned long end, pgprot_t prot, struct page **pages, int *nr,
 		pgtbl_mod_mask *mask)
 {
@@ -265,7 +265,7 @@ static int vmap_p4d_range(pgd_t *pgd, unsigned long addr,
 		return -ENOMEM;
 	do {
 		next = p4d_addr_end(addr, end);
-		if (vmap_pud_range(p4d, addr, next, prot, pages, nr, mask))
+		if (vmap_pages_pud_range(p4d, addr, next, prot, pages, nr, mask))
 			return -ENOMEM;
 	} while (p4d++, addr = next, addr != end);
 	return 0;
@@ -306,7 +306,7 @@ int map_kernel_range_noflush(unsigned long addr, unsigned long size,
 		next = pgd_addr_end(addr, end);
 		if (pgd_bad(*pgd))
 			mask |= PGTBL_PGD_MODIFIED;
-		err = vmap_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
+		err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
 		if (err)
 			return err;
 	} while (pgd++, addr = next, addr != end);
-- 
2.23.0

[PATCH v9 04/12] mm/ioremap: rename ioremap_*_range to vmap_*_range

[Nicholas Piggin]

This will be used as a generic kernel virtual mapping function, so
re-name it in preparation.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 mm/ioremap.c | 64 +++++++++++++++++++++++++++-------------------------
 1 file changed, 33 insertions(+), 31 deletions(-)

diff --git a/mm/ioremap.c b/mm/ioremap.c
index 5fa1ab41d152..3f4d36f9745a 100644
--- a/mm/ioremap.c
+++ b/mm/ioremap.c
@@ -61,9 +61,9 @@ static inline int ioremap_pud_enabled(void) { return 0; }
 static inline int ioremap_pmd_enabled(void) { return 0; }
 #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
-static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
-		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
-		pgtbl_mod_mask *mask)
+static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			pgtbl_mod_mask *mask)
 {
 	pte_t *pte;
 	u64 pfn;
@@ -81,9 +81,8 @@ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 
-static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
-				unsigned long end, phys_addr_t phys_addr,
-				pgprot_t prot)
+static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot)
 {
 	if (!ioremap_pmd_enabled())
 		return 0;
@@ -103,9 +102,9 @@ static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
 	return pmd_set_huge(pmd, phys_addr, prot);
 }
 
-static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
-		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
-		pgtbl_mod_mask *mask)
+static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			pgtbl_mod_mask *mask)
 {
 	pmd_t *pmd;
 	unsigned long next;
@@ -116,20 +115,19 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
 	do {
 		next = pmd_addr_end(addr, end);
 
-		if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
 			*mask |= PGTBL_PMD_MODIFIED;
 			continue;
 		}
 
-		if (ioremap_pte_range(pmd, addr, next, phys_addr, prot, mask))
+		if (vmap_pte_range(pmd, addr, next, phys_addr, prot, mask))
 			return -ENOMEM;
 	} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
-static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
-				unsigned long end, phys_addr_t phys_addr,
-				pgprot_t prot)
+static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot)
 {
 	if (!ioremap_pud_enabled())
 		return 0;
@@ -149,9 +147,9 @@ static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
 	return pud_set_huge(pud, phys_addr, prot);
 }
 
-static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
-		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
-		pgtbl_mod_mask *mask)
+static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			pgtbl_mod_mask *mask)
 {
 	pud_t *pud;
 	unsigned long next;
@@ -162,20 +160,19 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
 	do {
 		next = pud_addr_end(addr, end);
 
-		if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
 			*mask |= PGTBL_PUD_MODIFIED;
 			continue;
 		}
 
-		if (ioremap_pmd_range(pud, addr, next, phys_addr, prot, mask))
+		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, mask))
 			return -ENOMEM;
 	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
-static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
-				unsigned long end, phys_addr_t phys_addr,
-				pgprot_t prot)
+static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot)
 {
 	if (!ioremap_p4d_enabled())
 		return 0;
@@ -195,9 +192,9 @@ static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
 	return p4d_set_huge(p4d, phys_addr, prot);
 }
 
-static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
-		unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
-		pgtbl_mod_mask *mask)
+static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			pgtbl_mod_mask *mask)
 {
 	p4d_t *p4d;
 	unsigned long next;
@@ -208,19 +205,19 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
 	do {
 		next = p4d_addr_end(addr, end);
 
-		if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
 			*mask |= PGTBL_P4D_MODIFIED;
 			continue;
 		}
 
-		if (ioremap_pud_range(p4d, addr, next, phys_addr, prot, mask))
+		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, mask))
 			return -ENOMEM;
 	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
-int ioremap_page_range(unsigned long addr,
-		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
+static int vmap_range(unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot)
 {
 	pgd_t *pgd;
 	unsigned long start;
@@ -235,8 +232,7 @@ int ioremap_page_range(unsigned long addr,
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);
-		err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot,
-					&mask);
+		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, &mask);
 		if (err)
 			break;
 	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
@@ -249,6 +245,12 @@ int ioremap_page_range(unsigned long addr,
 	return err;
 }
 
+int ioremap_page_range(unsigned long addr,
+		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
+{
+	return vmap_range(addr, end, phys_addr, prot);
+}
+
 #ifdef CONFIG_GENERIC_IOREMAP
 void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
 {
-- 
2.23.0

[PATCH v9 05/12] mm: HUGE_VMAP arch support cleanup

[Nicholas Piggin]

This changes the awkward approach where architectures provide init
functions to determine which levels they can provide large mappings for,
to one where the arch is queried for each call.

This removes code and indirection, and allows constant-folding of dead
code for unsupported levels.

This also adds a prot argument to the arch query. This is unused
currently but could help with some architectures (e.g., some powerpc
processors can't map uncacheable memory with large pages).

Cc: linuxppc-dev@lists.ozlabs.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/arm64/include/asm/vmalloc.h         |  8 +++
 arch/arm64/mm/mmu.c                      | 10 +--
 arch/powerpc/include/asm/vmalloc.h       |  8 +++
 arch/powerpc/mm/book3s64/radix_pgtable.c |  8 +--
 arch/x86/include/asm/vmalloc.h           |  7 ++
 arch/x86/mm/ioremap.c                    | 10 +--
 include/linux/io.h                       |  9 ---
 include/linux/vmalloc.h                  |  6 ++
 init/main.c                              |  1 -
 mm/ioremap.c                             | 88 +++++++++---------------
 10 files changed, 77 insertions(+), 78 deletions(-)

diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index 2ca708ab9b20..597b40405319 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -1,4 +1,12 @@
 #ifndef _ASM_ARM64_VMALLOC_H
 #define _ASM_ARM64_VMALLOC_H
 
+#include <asm/page.h>
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+bool arch_vmap_p4d_supported(pgprot_t prot);
+bool arch_vmap_pud_supported(pgprot_t prot);
+bool arch_vmap_pmd_supported(pgprot_t prot);
+#endif
+
 #endif /* _ASM_ARM64_VMALLOC_H */
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index ca692a815731..1b60079c1cef 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1315,12 +1315,12 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 	return dt_virt;
 }
 
-int __init arch_ioremap_p4d_supported(void)
+bool arch_vmap_p4d_supported(pgprot_t prot)
 {
-	return 0;
+	return false;
 }
 
-int __init arch_ioremap_pud_supported(void)
+bool arch_vmap_pud_supported(pgprot_t prot);
 {
 	/*
 	 * Only 4k granule supports level 1 block mappings.
@@ -1330,9 +1330,9 @@ int __init arch_ioremap_pud_supported(void)
 	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
 }
 
-int __init arch_ioremap_pmd_supported(void)
+bool arch_vmap_pmd_supported(pgprot_t prot)
 {
-	/* See arch_ioremap_pud_supported() */
+	/* See arch_vmap_pud_supported() */
 	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
 }
 
diff --git a/arch/powerpc/include/asm/vmalloc.h b/arch/powerpc/include/asm/vmalloc.h
index b992dfaaa161..105abb73f075 100644
--- a/arch/powerpc/include/asm/vmalloc.h
+++ b/arch/powerpc/include/asm/vmalloc.h
@@ -1,4 +1,12 @@
 #ifndef _ASM_POWERPC_VMALLOC_H
 #define _ASM_POWERPC_VMALLOC_H
 
+#include <asm/page.h>
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+bool arch_vmap_p4d_supported(pgprot_t prot);
+bool arch_vmap_pud_supported(pgprot_t prot);
+bool arch_vmap_pmd_supported(pgprot_t prot);
+#endif
+
 #endif /* _ASM_POWERPC_VMALLOC_H */
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 3adcf730f478..ab426fc0cd4b 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1121,13 +1121,13 @@ void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
 	set_pte_at(mm, addr, ptep, pte);
 }
 
-int __init arch_ioremap_pud_supported(void)
+bool arch_vmap_pud_supported(pgprot_t prot)
 {
 	/* HPT does not cope with large pages in the vmalloc area */
 	return radix_enabled();
 }
 
-int __init arch_ioremap_pmd_supported(void)
+bool arch_vmap_pmd_supported(pgprot_t prot)
 {
 	return radix_enabled();
 }
@@ -1221,7 +1221,7 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 	return 1;
 }
 
-int __init arch_ioremap_p4d_supported(void)
+bool arch_vmap_p4d_supported(pgprot_t prot)
 {
-	return 0;
+	return false;
 }
diff --git a/arch/x86/include/asm/vmalloc.h b/arch/x86/include/asm/vmalloc.h
index 29837740b520..094ea2b565f3 100644
--- a/arch/x86/include/asm/vmalloc.h
+++ b/arch/x86/include/asm/vmalloc.h
@@ -1,6 +1,13 @@
 #ifndef _ASM_X86_VMALLOC_H
 #define _ASM_X86_VMALLOC_H
 
+#include <asm/page.h>
 #include <asm/pgtable_areas.h>
 
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+bool arch_vmap_p4d_supported(pgprot_t prot);
+bool arch_vmap_pud_supported(pgprot_t prot);
+bool arch_vmap_pmd_supported(pgprot_t prot);
+#endif
+
 #endif /* _ASM_X86_VMALLOC_H */
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 9e5ccc56f8e0..762b5ff4edad 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -481,21 +481,21 @@ void iounmap(volatile void __iomem *addr)
 }
 EXPORT_SYMBOL(iounmap);
 
-int __init arch_ioremap_p4d_supported(void)
+bool arch_vmap_p4d_supported(pgprot_t prot)
 {
-	return 0;
+	return false;
 }
 
-int __init arch_ioremap_pud_supported(void)
+bool arch_vmap_pud_supported(pgprot_t prot)
 {
 #ifdef CONFIG_X86_64
 	return boot_cpu_has(X86_FEATURE_GBPAGES);
 #else
-	return 0;
+	return false;
 #endif
 }
 
-int __init arch_ioremap_pmd_supported(void)
+bool arch_vmap_pmd_supported(pgprot_t prot)
 {
 	return boot_cpu_has(X86_FEATURE_PSE);
 }
diff --git a/include/linux/io.h b/include/linux/io.h
index 8394c56babc2..f1effd4d7a3c 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -31,15 +31,6 @@ static inline int ioremap_page_range(unsigned long addr, unsigned long end,
 }
 #endif
 
-#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-void __init ioremap_huge_init(void);
-int arch_ioremap_p4d_supported(void);
-int arch_ioremap_pud_supported(void);
-int arch_ioremap_pmd_supported(void);
-#else
-static inline void ioremap_huge_init(void) { }
-#endif
-
 /*
  * Managed iomap interface
  */
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 938eaf9517e2..b3218ba0904d 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -85,6 +85,12 @@ struct vmap_area {
 	};
 };
 
+#ifndef CONFIG_HAVE_ARCH_HUGE_VMAP
+static inline bool arch_vmap_p4d_supported(pgprot_t prot) { return false; }
+static inline bool arch_vmap_pud_supported(pgprot_t prot) { return false; }
+static inline bool arch_vmap_pmd_supported(pgprot_t prot) { return false; }
+#endif
+
 /*
  *	Highlevel APIs for driver use
  */
diff --git a/init/main.c b/init/main.c
index 20baced721ad..5bd2f4f41d30 100644
--- a/init/main.c
+++ b/init/main.c
@@ -833,7 +833,6 @@ static void __init mm_init(void)
 	pgtable_init();
 	debug_objects_mem_init();
 	vmalloc_init();
-	ioremap_huge_init();
 	/* Should be run before the first non-init thread is created */
 	init_espfix_bsp();
 	/* Should be run after espfix64 is set up. */
diff --git a/mm/ioremap.c b/mm/ioremap.c
index 3f4d36f9745a..c67f91164401 100644
--- a/mm/ioremap.c
+++ b/mm/ioremap.c
@@ -16,49 +16,16 @@
 #include "pgalloc-track.h"
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-static int __read_mostly ioremap_p4d_capable;
-static int __read_mostly ioremap_pud_capable;
-static int __read_mostly ioremap_pmd_capable;
-static int __read_mostly ioremap_huge_disabled;
+static bool __ro_after_init iomap_max_page_shift = PAGE_SHIFT;
 
 static int __init set_nohugeiomap(char *str)
 {
-	ioremap_huge_disabled = 1;
+	iomap_max_page_shift = P4D_SHIFT;
 	return 0;
 }
 early_param("nohugeiomap", set_nohugeiomap);
-
-void __init ioremap_huge_init(void)
-{
-	if (!ioremap_huge_disabled) {
-		if (arch_ioremap_p4d_supported())
-			ioremap_p4d_capable = 1;
-		if (arch_ioremap_pud_supported())
-			ioremap_pud_capable = 1;
-		if (arch_ioremap_pmd_supported())
-			ioremap_pmd_capable = 1;
-	}
-}
-
-static inline int ioremap_p4d_enabled(void)
-{
-	return ioremap_p4d_capable;
-}
-
-static inline int ioremap_pud_enabled(void)
-{
-	return ioremap_pud_capable;
-}
-
-static inline int ioremap_pmd_enabled(void)
-{
-	return ioremap_pmd_capable;
-}
-
-#else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */
-static inline int ioremap_p4d_enabled(void) { return 0; }
-static inline int ioremap_pud_enabled(void) { return 0; }
-static inline int ioremap_pmd_enabled(void) { return 0; }
+#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+static const bool iomap_max_page_shift = PAGE_SHIFT;
 #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
 static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
@@ -82,9 +49,13 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 }
 
 static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
-	if (!ioremap_pmd_enabled())
+	if (max_page_shift < PMD_SHIFT)
+		return 0;
+
+	if (!arch_vmap_pmd_supported(prot))
 		return 0;
 
 	if ((end - addr) != PMD_SIZE)
@@ -104,7 +75,7 @@ static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
 
 static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 			phys_addr_t phys_addr, pgprot_t prot,
-			pgtbl_mod_mask *mask)
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
 {
 	pmd_t *pmd;
 	unsigned long next;
@@ -115,7 +86,7 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 	do {
 		next = pmd_addr_end(addr, end);
 
-		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot, max_page_shift)) {
 			*mask |= PGTBL_PMD_MODIFIED;
 			continue;
 		}
@@ -127,9 +98,13 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 }
 
 static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
-	if (!ioremap_pud_enabled())
+	if (max_page_shift < PUD_SHIFT)
+		return 0;
+
+	if (!arch_vmap_pud_supported(prot))
 		return 0;
 
 	if ((end - addr) != PUD_SIZE)
@@ -149,7 +124,7 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
 
 static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
 			phys_addr_t phys_addr, pgprot_t prot,
-			pgtbl_mod_mask *mask)
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
 {
 	pud_t *pud;
 	unsigned long next;
@@ -160,21 +135,25 @@ static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
 	do {
 		next = pud_addr_end(addr, end);
 
-		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot, max_page_shift)) {
 			*mask |= PGTBL_PUD_MODIFIED;
 			continue;
 		}
 
-		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, mask))
+		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, max_page_shift, mask))
 			return -ENOMEM;
 	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
 static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
-	if (!ioremap_p4d_enabled())
+	if (max_page_shift < P4D_SHIFT)
+		return 0;
+
+	if (!arch_vmap_p4d_supported(prot))
 		return 0;
 
 	if ((end - addr) != P4D_SIZE)
@@ -194,7 +173,7 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
 
 static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 			phys_addr_t phys_addr, pgprot_t prot,
-			pgtbl_mod_mask *mask)
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
 {
 	p4d_t *p4d;
 	unsigned long next;
@@ -205,19 +184,20 @@ static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 	do {
 		next = p4d_addr_end(addr, end);
 
-		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
+		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot, max_page_shift)) {
 			*mask |= PGTBL_P4D_MODIFIED;
 			continue;
 		}
 
-		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, mask))
+		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, max_page_shift, mask))
 			return -ENOMEM;
 	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
 static int vmap_range(unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot)
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
 {
 	pgd_t *pgd;
 	unsigned long start;
@@ -232,7 +212,7 @@ static int vmap_range(unsigned long addr, unsigned long end,
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);
-		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, &mask);
+		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, max_page_shift, &mask);
 		if (err)
 			break;
 	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
@@ -248,7 +228,7 @@ static int vmap_range(unsigned long addr, unsigned long end,
 int ioremap_page_range(unsigned long addr,
 		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {
-	return vmap_range(addr, end, phys_addr, prot);
+	return vmap_range(addr, end, phys_addr, prot, iomap_max_page_shift);
 }
 
 #ifdef CONFIG_GENERIC_IOREMAP
-- 
2.23.0

Re: [PATCH v9 05/12] mm: HUGE_VMAP arch support cleanup

[Ding Tianhong]

On 2020/12/5 14:57, Nicholas Piggin wrote:
> This changes the awkward approach where architectures provide init
> functions to determine which levels they can provide large mappings for,
> to one where the arch is queried for each call.
> 
> This removes code and indirection, and allows constant-folding of dead
> code for unsupported levels.
> 
> This also adds a prot argument to the arch query. This is unused
> currently but could help with some architectures (e.g., some powerpc
> processors can't map uncacheable memory with large pages).
> 
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: x86@kernel.org
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/arm64/include/asm/vmalloc.h         |  8 +++
>  arch/arm64/mm/mmu.c                      | 10 +--
>  arch/powerpc/include/asm/vmalloc.h       |  8 +++
>  arch/powerpc/mm/book3s64/radix_pgtable.c |  8 +--
>  arch/x86/include/asm/vmalloc.h           |  7 ++
>  arch/x86/mm/ioremap.c                    | 10 +--
>  include/linux/io.h                       |  9 ---
>  include/linux/vmalloc.h                  |  6 ++
>  init/main.c                              |  1 -
>  mm/ioremap.c                             | 88 +++++++++---------------
>  10 files changed, 77 insertions(+), 78 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
> index 2ca708ab9b20..597b40405319 100644
> --- a/arch/arm64/include/asm/vmalloc.h
> +++ b/arch/arm64/include/asm/vmalloc.h
> @@ -1,4 +1,12 @@
>  #ifndef _ASM_ARM64_VMALLOC_H
>  #define _ASM_ARM64_VMALLOC_H
>  
> +#include <asm/page.h>
> +
> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> +bool arch_vmap_p4d_supported(pgprot_t prot);
> +bool arch_vmap_pud_supported(pgprot_t prot);
> +bool arch_vmap_pmd_supported(pgprot_t prot);
> +#endif
> +
>  #endif /* _ASM_ARM64_VMALLOC_H */
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index ca692a815731..1b60079c1cef 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -1315,12 +1315,12 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
>  	return dt_virt;
>  }
>  
> -int __init arch_ioremap_p4d_supported(void)
> +bool arch_vmap_p4d_supported(pgprot_t prot)
>  {
> -	return 0;
> +	return false;
>  }
>  

I think you should put this function in the CONFIG_HAVE_ARCH_HUGE_VMAP, otherwise it may break the compile when disable the CONFIG_HAVE_ARCH_HUGE_VMAP, the same
as the x86 and ppc.

Ding

> -int __init arch_ioremap_pud_supported(void)
> +bool arch_vmap_pud_supported(pgprot_t prot);
>  {
>  	/*
>  	 * Only 4k granule supports level 1 block mappings.
> @@ -1330,9 +1330,9 @@ int __init arch_ioremap_pud_supported(void)
>  	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
>  }
>  
> -int __init arch_ioremap_pmd_supported(void)
> +bool arch_vmap_pmd_supported(pgprot_t prot)
>  {
> -	/* See arch_ioremap_pud_supported() */
> +	/* See arch_vmap_pud_supported() */
>  	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
>  }
>  
> diff --git a/arch/powerpc/include/asm/vmalloc.h b/arch/powerpc/include/asm/vmalloc.h
> index b992dfaaa161..105abb73f075 100644
> --- a/arch/powerpc/include/asm/vmalloc.h
> +++ b/arch/powerpc/include/asm/vmalloc.h
> @@ -1,4 +1,12 @@
>  #ifndef _ASM_POWERPC_VMALLOC_H
>  #define _ASM_POWERPC_VMALLOC_H
>  
> +#include <asm/page.h>
> +
> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> +bool arch_vmap_p4d_supported(pgprot_t prot);
> +bool arch_vmap_pud_supported(pgprot_t prot);
> +bool arch_vmap_pmd_supported(pgprot_t prot);
> +#endif
> +
>  #endif /* _ASM_POWERPC_VMALLOC_H */
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index 3adcf730f478..ab426fc0cd4b 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -1121,13 +1121,13 @@ void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
>  	set_pte_at(mm, addr, ptep, pte);
>  }
>  
> -int __init arch_ioremap_pud_supported(void)
> +bool arch_vmap_pud_supported(pgprot_t prot)
>  {
>  	/* HPT does not cope with large pages in the vmalloc area */
>  	return radix_enabled();
>  }
>  
> -int __init arch_ioremap_pmd_supported(void)
> +bool arch_vmap_pmd_supported(pgprot_t prot)
>  {
>  	return radix_enabled();
>  }
> @@ -1221,7 +1221,7 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
>  	return 1;
>  }
>  
> -int __init arch_ioremap_p4d_supported(void)
> +bool arch_vmap_p4d_supported(pgprot_t prot)
>  {
> -	return 0;
> +	return false;
>  }
> diff --git a/arch/x86/include/asm/vmalloc.h b/arch/x86/include/asm/vmalloc.h
> index 29837740b520..094ea2b565f3 100644
> --- a/arch/x86/include/asm/vmalloc.h
> +++ b/arch/x86/include/asm/vmalloc.h
> @@ -1,6 +1,13 @@
>  #ifndef _ASM_X86_VMALLOC_H
>  #define _ASM_X86_VMALLOC_H
>  
> +#include <asm/page.h>
>  #include <asm/pgtable_areas.h>
>  
> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> +bool arch_vmap_p4d_supported(pgprot_t prot);
> +bool arch_vmap_pud_supported(pgprot_t prot);
> +bool arch_vmap_pmd_supported(pgprot_t prot);
> +#endif
> +
>  #endif /* _ASM_X86_VMALLOC_H */
> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
> index 9e5ccc56f8e0..762b5ff4edad 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -481,21 +481,21 @@ void iounmap(volatile void __iomem *addr)
>  }
>  EXPORT_SYMBOL(iounmap);
>  
> -int __init arch_ioremap_p4d_supported(void)
> +bool arch_vmap_p4d_supported(pgprot_t prot)
>  {
> -	return 0;
> +	return false;
>  }
>  
> -int __init arch_ioremap_pud_supported(void)
> +bool arch_vmap_pud_supported(pgprot_t prot)
>  {
>  #ifdef CONFIG_X86_64
>  	return boot_cpu_has(X86_FEATURE_GBPAGES);
>  #else
> -	return 0;
> +	return false;
>  #endif
>  }
>  
> -int __init arch_ioremap_pmd_supported(void)
> +bool arch_vmap_pmd_supported(pgprot_t prot)
>  {
>  	return boot_cpu_has(X86_FEATURE_PSE);
>  }
> diff --git a/include/linux/io.h b/include/linux/io.h
> index 8394c56babc2..f1effd4d7a3c 100644
> --- a/include/linux/io.h
> +++ b/include/linux/io.h
> @@ -31,15 +31,6 @@ static inline int ioremap_page_range(unsigned long addr, unsigned long end,
>  }
>  #endif
>  
> -#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> -void __init ioremap_huge_init(void);
> -int arch_ioremap_p4d_supported(void);
> -int arch_ioremap_pud_supported(void);
> -int arch_ioremap_pmd_supported(void);
> -#else
> -static inline void ioremap_huge_init(void) { }
> -#endif
> -
>  /*
>   * Managed iomap interface
>   */
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index 938eaf9517e2..b3218ba0904d 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -85,6 +85,12 @@ struct vmap_area {
>  	};
>  };
>  
> +#ifndef CONFIG_HAVE_ARCH_HUGE_VMAP
> +static inline bool arch_vmap_p4d_supported(pgprot_t prot) { return false; }
> +static inline bool arch_vmap_pud_supported(pgprot_t prot) { return false; }
> +static inline bool arch_vmap_pmd_supported(pgprot_t prot) { return false; }
> +#endif
> +
>  /*
>   *	Highlevel APIs for driver use
>   */
> diff --git a/init/main.c b/init/main.c
> index 20baced721ad..5bd2f4f41d30 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -833,7 +833,6 @@ static void __init mm_init(void)
>  	pgtable_init();
>  	debug_objects_mem_init();
>  	vmalloc_init();
> -	ioremap_huge_init();
>  	/* Should be run before the first non-init thread is created */
>  	init_espfix_bsp();
>  	/* Should be run after espfix64 is set up. */
> diff --git a/mm/ioremap.c b/mm/ioremap.c
> index 3f4d36f9745a..c67f91164401 100644
> --- a/mm/ioremap.c
> +++ b/mm/ioremap.c
> @@ -16,49 +16,16 @@
>  #include "pgalloc-track.h"
>  
>  #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
> -static int __read_mostly ioremap_p4d_capable;
> -static int __read_mostly ioremap_pud_capable;
> -static int __read_mostly ioremap_pmd_capable;
> -static int __read_mostly ioremap_huge_disabled;
> +static bool __ro_after_init iomap_max_page_shift = PAGE_SHIFT;
>  
>  static int __init set_nohugeiomap(char *str)
>  {
> -	ioremap_huge_disabled = 1;
> +	iomap_max_page_shift = P4D_SHIFT;
>  	return 0;
>  }
>  early_param("nohugeiomap", set_nohugeiomap);
> -
> -void __init ioremap_huge_init(void)
> -{
> -	if (!ioremap_huge_disabled) {
> -		if (arch_ioremap_p4d_supported())
> -			ioremap_p4d_capable = 1;
> -		if (arch_ioremap_pud_supported())
> -			ioremap_pud_capable = 1;
> -		if (arch_ioremap_pmd_supported())
> -			ioremap_pmd_capable = 1;
> -	}
> -}
> -
> -static inline int ioremap_p4d_enabled(void)
> -{
> -	return ioremap_p4d_capable;
> -}
> -
> -static inline int ioremap_pud_enabled(void)
> -{
> -	return ioremap_pud_capable;
> -}
> -
> -static inline int ioremap_pmd_enabled(void)
> -{
> -	return ioremap_pmd_capable;
> -}
> -
> -#else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */
> -static inline int ioremap_p4d_enabled(void) { return 0; }
> -static inline int ioremap_pud_enabled(void) { return 0; }
> -static inline int ioremap_pmd_enabled(void) { return 0; }
> +#else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
> +static const bool iomap_max_page_shift = PAGE_SHIFT;
>  #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
>  
>  static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
> @@ -82,9 +49,13 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>  }
>  
>  static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
> -			phys_addr_t phys_addr, pgprot_t prot)
> +			phys_addr_t phys_addr, pgprot_t prot,
> +			unsigned int max_page_shift)
>  {
> -	if (!ioremap_pmd_enabled())
> +	if (max_page_shift < PMD_SHIFT)
> +		return 0;
> +
> +	if (!arch_vmap_pmd_supported(prot))
>  		return 0;
>  
>  	if ((end - addr) != PMD_SIZE)
> @@ -104,7 +75,7 @@ static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
>  
>  static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
>  			phys_addr_t phys_addr, pgprot_t prot,
> -			pgtbl_mod_mask *mask)
> +			unsigned int max_page_shift, pgtbl_mod_mask *mask)
>  {
>  	pmd_t *pmd;
>  	unsigned long next;
> @@ -115,7 +86,7 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
>  	do {
>  		next = pmd_addr_end(addr, end);
>  
> -		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
> +		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot, max_page_shift)) {
>  			*mask |= PGTBL_PMD_MODIFIED;
>  			continue;
>  		}
> @@ -127,9 +98,13 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
>  }
>  
>  static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
> -			phys_addr_t phys_addr, pgprot_t prot)
> +			phys_addr_t phys_addr, pgprot_t prot,
> +			unsigned int max_page_shift)
>  {
> -	if (!ioremap_pud_enabled())
> +	if (max_page_shift < PUD_SHIFT)
> +		return 0;
> +
> +	if (!arch_vmap_pud_supported(prot))
>  		return 0;
>  
>  	if ((end - addr) != PUD_SIZE)
> @@ -149,7 +124,7 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
>  
>  static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
>  			phys_addr_t phys_addr, pgprot_t prot,
> -			pgtbl_mod_mask *mask)
> +			unsigned int max_page_shift, pgtbl_mod_mask *mask)
>  {
>  	pud_t *pud;
>  	unsigned long next;
> @@ -160,21 +135,25 @@ static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
>  	do {
>  		next = pud_addr_end(addr, end);
>  
> -		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
> +		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot, max_page_shift)) {
>  			*mask |= PGTBL_PUD_MODIFIED;
>  			continue;
>  		}
>  
> -		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, mask))
> +		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, max_page_shift, mask))
>  			return -ENOMEM;
>  	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
>  	return 0;
>  }
>  
>  static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
> -			phys_addr_t phys_addr, pgprot_t prot)
> +			phys_addr_t phys_addr, pgprot_t prot,
> +			unsigned int max_page_shift)
>  {
> -	if (!ioremap_p4d_enabled())
> +	if (max_page_shift < P4D_SHIFT)
> +		return 0;
> +
> +	if (!arch_vmap_p4d_supported(prot))
>  		return 0;
>  
>  	if ((end - addr) != P4D_SIZE)
> @@ -194,7 +173,7 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
>  
>  static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
>  			phys_addr_t phys_addr, pgprot_t prot,
> -			pgtbl_mod_mask *mask)
> +			unsigned int max_page_shift, pgtbl_mod_mask *mask)
>  {
>  	p4d_t *p4d;
>  	unsigned long next;
> @@ -205,19 +184,20 @@ static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
>  	do {
>  		next = p4d_addr_end(addr, end);
>  
> -		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
> +		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot, max_page_shift)) {
>  			*mask |= PGTBL_P4D_MODIFIED;
>  			continue;
>  		}
>  
> -		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, mask))
> +		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, max_page_shift, mask))
>  			return -ENOMEM;
>  	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
>  	return 0;
>  }
>  
>  static int vmap_range(unsigned long addr, unsigned long end,
> -			phys_addr_t phys_addr, pgprot_t prot)
> +			phys_addr_t phys_addr, pgprot_t prot,
> +			unsigned int max_page_shift)
>  {
>  	pgd_t *pgd;
>  	unsigned long start;
> @@ -232,7 +212,7 @@ static int vmap_range(unsigned long addr, unsigned long end,
>  	pgd = pgd_offset_k(addr);
>  	do {
>  		next = pgd_addr_end(addr, end);
> -		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, &mask);
> +		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, max_page_shift, &mask);
>  		if (err)
>  			break;
>  	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
> @@ -248,7 +228,7 @@ static int vmap_range(unsigned long addr, unsigned long end,
>  int ioremap_page_range(unsigned long addr,
>  		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
>  {
> -	return vmap_range(addr, end, phys_addr, prot);
> +	return vmap_range(addr, end, phys_addr, prot, iomap_max_page_shift);
>  }
>  
>  #ifdef CONFIG_GENERIC_IOREMAP
> 

Re: [PATCH v9 05/12] mm: HUGE_VMAP arch support cleanup

[Nicholas Piggin]

Excerpts from Ding Tianhong's message of January 4, 2021 10:33 pm:
> On 2020/12/5 14:57, Nicholas Piggin wrote:
>> This changes the awkward approach where architectures provide init
>> functions to determine which levels they can provide large mappings for,
>> to one where the arch is queried for each call.
>> 
>> This removes code and indirection, and allows constant-folding of dead
>> code for unsupported levels.
>> 
>> This also adds a prot argument to the arch query. This is unused
>> currently but could help with some architectures (e.g., some powerpc
>> processors can't map uncacheable memory with large pages).
>> 
>> Cc: linuxppc-dev@lists.ozlabs.org
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Borislav Petkov <bp@alien8.de>
>> Cc: x86@kernel.org
>> Cc: "H. Peter Anvin" <hpa@zytor.com>
>> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>> ---
>>  arch/arm64/include/asm/vmalloc.h         |  8 +++
>>  arch/arm64/mm/mmu.c                      | 10 +--
>>  arch/powerpc/include/asm/vmalloc.h       |  8 +++
>>  arch/powerpc/mm/book3s64/radix_pgtable.c |  8 +--
>>  arch/x86/include/asm/vmalloc.h           |  7 ++
>>  arch/x86/mm/ioremap.c                    | 10 +--
>>  include/linux/io.h                       |  9 ---
>>  include/linux/vmalloc.h                  |  6 ++
>>  init/main.c                              |  1 -
>>  mm/ioremap.c                             | 88 +++++++++---------------
>>  10 files changed, 77 insertions(+), 78 deletions(-)
>> 
>> diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
>> index 2ca708ab9b20..597b40405319 100644
>> --- a/arch/arm64/include/asm/vmalloc.h
>> +++ b/arch/arm64/include/asm/vmalloc.h
>> @@ -1,4 +1,12 @@
>>  #ifndef _ASM_ARM64_VMALLOC_H
>>  #define _ASM_ARM64_VMALLOC_H
>>  
>> +#include <asm/page.h>
>> +
>> +#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
>> +bool arch_vmap_p4d_supported(pgprot_t prot);
>> +bool arch_vmap_pud_supported(pgprot_t prot);
>> +bool arch_vmap_pmd_supported(pgprot_t prot);
>> +#endif
>> +
>>  #endif /* _ASM_ARM64_VMALLOC_H */
>> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
>> index ca692a815731..1b60079c1cef 100644
>> --- a/arch/arm64/mm/mmu.c
>> +++ b/arch/arm64/mm/mmu.c
>> @@ -1315,12 +1315,12 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
>>  	return dt_virt;
>>  }
>>  
>> -int __init arch_ioremap_p4d_supported(void)
>> +bool arch_vmap_p4d_supported(pgprot_t prot)
>>  {
>> -	return 0;
>> +	return false;
>>  }
>>  
> 
> I think you should put this function in the CONFIG_HAVE_ARCH_HUGE_VMAP, otherwise it may break the compile when disable the CONFIG_HAVE_ARCH_HUGE_VMAP, the same
> as the x86 and ppc.

Ah, good catch. arm64 is okay because it always selects 
HAVE_ARCH_HUGE_VMAP, powerpc is okay because it places
them in a file that's only compiled for configs that select
huge vmap, but x86-32 without PAE build breaks. I'll fix that.

Thanks,
Nick

[PATCH v9 06/12] powerpc: inline huge vmap supported functions

[Nicholas Piggin]

This allows unsupported levels to be constant folded away, and so
p4d_free_pud_page can be removed because it's no longer linked to.

Cc: linuxppc-dev@lists.ozlabs.org
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/include/asm/vmalloc.h       | 19 ++++++++++++++++---
 arch/powerpc/mm/book3s64/radix_pgtable.c | 21 ---------------------
 2 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/arch/powerpc/include/asm/vmalloc.h b/arch/powerpc/include/asm/vmalloc.h
index 105abb73f075..3f0c153befb0 100644
--- a/arch/powerpc/include/asm/vmalloc.h
+++ b/arch/powerpc/include/asm/vmalloc.h
@@ -1,12 +1,25 @@
 #ifndef _ASM_POWERPC_VMALLOC_H
 #define _ASM_POWERPC_VMALLOC_H
 
+#include <asm/mmu.h>
 #include <asm/page.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-bool arch_vmap_p4d_supported(pgprot_t prot);
-bool arch_vmap_pud_supported(pgprot_t prot);
-bool arch_vmap_pmd_supported(pgprot_t prot);
+static inline bool arch_vmap_p4d_supported(pgprot_t prot)
+{
+	return false;
+}
+
+static inline bool arch_vmap_pud_supported(pgprot_t prot)
+{
+	/* HPT does not cope with large pages in the vmalloc area */
+	return radix_enabled();
+}
+
+static inline bool arch_vmap_pmd_supported(pgprot_t prot)
+{
+	return radix_enabled();
+}
 #endif
 
 #endif /* _ASM_POWERPC_VMALLOC_H */
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index ab426fc0cd4b..de6b558dc187 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1121,22 +1121,6 @@ void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
 	set_pte_at(mm, addr, ptep, pte);
 }
 
-bool arch_vmap_pud_supported(pgprot_t prot)
-{
-	/* HPT does not cope with large pages in the vmalloc area */
-	return radix_enabled();
-}
-
-bool arch_vmap_pmd_supported(pgprot_t prot)
-{
-	return radix_enabled();
-}
-
-int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
-{
-	return 0;
-}
-
 int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
 {
 	pte_t *ptep = (pte_t *)pud;
@@ -1220,8 +1204,3 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 
 	return 1;
 }
-
-bool arch_vmap_p4d_supported(pgprot_t prot)
-{
-	return false;
-}
-- 
2.23.0

[PATCH v9 07/12] arm64: inline huge vmap supported functions

[Nicholas Piggin]

This allows unsupported levels to be constant folded away, and so
p4d_free_pud_page can be removed because it's no longer linked to.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/arm64/include/asm/vmalloc.h | 23 ++++++++++++++++++++---
 arch/arm64/mm/mmu.c              | 26 --------------------------
 2 files changed, 20 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index 597b40405319..fc9a12d6cc1a 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -4,9 +4,26 @@
 #include <asm/page.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-bool arch_vmap_p4d_supported(pgprot_t prot);
-bool arch_vmap_pud_supported(pgprot_t prot);
-bool arch_vmap_pmd_supported(pgprot_t prot);
+static inline bool arch_vmap_p4d_supported(pgprot_t prot)
+{
+	return false;
+}
+
+static inline bool arch_vmap_pud_supported(pgprot_t prot)
+{
+	/*
+	 * Only 4k granule supports level 1 block mappings.
+	 * SW table walks can't handle removal of intermediate entries.
+	 */
+	return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
+	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
+}
+
+static inline bool arch_vmap_pmd_supported(pgprot_t prot)
+{
+	/* See arch_vmap_pud_supported() */
+	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
+}
 #endif
 
 #endif /* _ASM_ARM64_VMALLOC_H */
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 1b60079c1cef..0af5b5cfb9c6 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1315,27 +1315,6 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 	return dt_virt;
 }
 
-bool arch_vmap_p4d_supported(pgprot_t prot)
-{
-	return false;
-}
-
-bool arch_vmap_pud_supported(pgprot_t prot);
-{
-	/*
-	 * Only 4k granule supports level 1 block mappings.
-	 * SW table walks can't handle removal of intermediate entries.
-	 */
-	return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
-	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
-}
-
-bool arch_vmap_pmd_supported(pgprot_t prot)
-{
-	/* See arch_vmap_pud_supported() */
-	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
-}
-
 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
 {
 	pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
@@ -1427,11 +1406,6 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
 	return 1;
 }
 
-int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
-{
-	return 0;	/* Don't attempt a block mapping */
-}
-
 #ifdef CONFIG_MEMORY_HOTPLUG
 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
 {
-- 
2.23.0

[PATCH v9 08/12] x86: inline huge vmap supported functions

[Nicholas Piggin]

This allows unsupported levels to be constant folded away, and so
p4d_free_pud_page can be removed because it's no longer linked to.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/x86/include/asm/vmalloc.h | 22 +++++++++++++++++++---
 arch/x86/mm/ioremap.c          | 19 -------------------
 arch/x86/mm/pgtable.c          | 13 -------------
 3 files changed, 19 insertions(+), 35 deletions(-)

diff --git a/arch/x86/include/asm/vmalloc.h b/arch/x86/include/asm/vmalloc.h
index 094ea2b565f3..e714b00fc0ca 100644
--- a/arch/x86/include/asm/vmalloc.h
+++ b/arch/x86/include/asm/vmalloc.h
@@ -1,13 +1,29 @@
 #ifndef _ASM_X86_VMALLOC_H
 #define _ASM_X86_VMALLOC_H
 
+#include <asm/cpufeature.h>
 #include <asm/page.h>
 #include <asm/pgtable_areas.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-bool arch_vmap_p4d_supported(pgprot_t prot);
-bool arch_vmap_pud_supported(pgprot_t prot);
-bool arch_vmap_pmd_supported(pgprot_t prot);
+static inline bool arch_vmap_p4d_supported(pgprot_t prot)
+{
+	return false;
+}
+
+static inline bool arch_vmap_pud_supported(pgprot_t prot)
+{
+#ifdef CONFIG_X86_64
+	return boot_cpu_has(X86_FEATURE_GBPAGES);
+#else
+	return false;
+#endif
+}
+
+static inline bool arch_vmap_pmd_supported(pgprot_t prot)
+{
+	return boot_cpu_has(X86_FEATURE_PSE);
+}
 #endif
 
 #endif /* _ASM_X86_VMALLOC_H */
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 762b5ff4edad..12c686c65ea9 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -481,25 +481,6 @@ void iounmap(volatile void __iomem *addr)
 }
 EXPORT_SYMBOL(iounmap);
 
-bool arch_vmap_p4d_supported(pgprot_t prot)
-{
-	return false;
-}
-
-bool arch_vmap_pud_supported(pgprot_t prot)
-{
-#ifdef CONFIG_X86_64
-	return boot_cpu_has(X86_FEATURE_GBPAGES);
-#else
-	return false;
-#endif
-}
-
-bool arch_vmap_pmd_supported(pgprot_t prot)
-{
-	return boot_cpu_has(X86_FEATURE_PSE);
-}
-
 /*
  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
  * access
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index dfd82f51ba66..801c418ee97d 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -780,14 +780,6 @@ int pmd_clear_huge(pmd_t *pmd)
 	return 0;
 }
 
-/*
- * Until we support 512GB pages, skip them in the vmap area.
- */
-int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
-{
-	return 0;
-}
-
 #ifdef CONFIG_X86_64
 /**
  * pud_free_pmd_page - Clear pud entry and free pmd page.
@@ -859,11 +851,6 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 
 #else /* !CONFIG_X86_64 */
 
-int pud_free_pmd_page(pud_t *pud, unsigned long addr)
-{
-	return pud_none(*pud);
-}
-
 /*
  * Disable free page handling on x86-PAE. This assures that ioremap()
  * does not update sync'd pmd entries. See vmalloc_sync_one().
-- 
2.23.0

[PATCH v9 09/12] mm: Move vmap_range from mm/ioremap.c to mm/vmalloc.c

[Nicholas Piggin]

This is a generic kernel virtual memory mapper, not specific to ioremap.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 include/linux/vmalloc.h |   3 +
 mm/ioremap.c            | 197 ----------------------------------------
 mm/vmalloc.c            | 196 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 199 insertions(+), 197 deletions(-)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index b3218ba0904d..a5ae791dc1e0 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -180,6 +180,9 @@ extern struct vm_struct *remove_vm_area(const void *addr);
 extern struct vm_struct *find_vm_area(const void *addr);
 
 #ifdef CONFIG_MMU
+int vmap_range(unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift);
 extern int map_kernel_range_noflush(unsigned long start, unsigned long size,
 				    pgprot_t prot, struct page **pages);
 int map_kernel_range(unsigned long start, unsigned long size, pgprot_t prot,
diff --git a/mm/ioremap.c b/mm/ioremap.c
index c67f91164401..d1dcc7e744ac 100644
--- a/mm/ioremap.c
+++ b/mm/ioremap.c
@@ -28,203 +28,6 @@ early_param("nohugeiomap", set_nohugeiomap);
 static const bool iomap_max_page_shift = PAGE_SHIFT;
 #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
-static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			pgtbl_mod_mask *mask)
-{
-	pte_t *pte;
-	u64 pfn;
-
-	pfn = phys_addr >> PAGE_SHIFT;
-	pte = pte_alloc_kernel_track(pmd, addr, mask);
-	if (!pte)
-		return -ENOMEM;
-	do {
-		BUG_ON(!pte_none(*pte));
-		set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
-		pfn++;
-	} while (pte++, addr += PAGE_SIZE, addr != end);
-	*mask |= PGTBL_PTE_MODIFIED;
-	return 0;
-}
-
-static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			unsigned int max_page_shift)
-{
-	if (max_page_shift < PMD_SHIFT)
-		return 0;
-
-	if (!arch_vmap_pmd_supported(prot))
-		return 0;
-
-	if ((end - addr) != PMD_SIZE)
-		return 0;
-
-	if (!IS_ALIGNED(addr, PMD_SIZE))
-		return 0;
-
-	if (!IS_ALIGNED(phys_addr, PMD_SIZE))
-		return 0;
-
-	if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
-		return 0;
-
-	return pmd_set_huge(pmd, phys_addr, prot);
-}
-
-static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			unsigned int max_page_shift, pgtbl_mod_mask *mask)
-{
-	pmd_t *pmd;
-	unsigned long next;
-
-	pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
-	if (!pmd)
-		return -ENOMEM;
-	do {
-		next = pmd_addr_end(addr, end);
-
-		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot, max_page_shift)) {
-			*mask |= PGTBL_PMD_MODIFIED;
-			continue;
-		}
-
-		if (vmap_pte_range(pmd, addr, next, phys_addr, prot, mask))
-			return -ENOMEM;
-	} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
-	return 0;
-}
-
-static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			unsigned int max_page_shift)
-{
-	if (max_page_shift < PUD_SHIFT)
-		return 0;
-
-	if (!arch_vmap_pud_supported(prot))
-		return 0;
-
-	if ((end - addr) != PUD_SIZE)
-		return 0;
-
-	if (!IS_ALIGNED(addr, PUD_SIZE))
-		return 0;
-
-	if (!IS_ALIGNED(phys_addr, PUD_SIZE))
-		return 0;
-
-	if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
-		return 0;
-
-	return pud_set_huge(pud, phys_addr, prot);
-}
-
-static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			unsigned int max_page_shift, pgtbl_mod_mask *mask)
-{
-	pud_t *pud;
-	unsigned long next;
-
-	pud = pud_alloc_track(&init_mm, p4d, addr, mask);
-	if (!pud)
-		return -ENOMEM;
-	do {
-		next = pud_addr_end(addr, end);
-
-		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot, max_page_shift)) {
-			*mask |= PGTBL_PUD_MODIFIED;
-			continue;
-		}
-
-		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, max_page_shift, mask))
-			return -ENOMEM;
-	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
-	return 0;
-}
-
-static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			unsigned int max_page_shift)
-{
-	if (max_page_shift < P4D_SHIFT)
-		return 0;
-
-	if (!arch_vmap_p4d_supported(prot))
-		return 0;
-
-	if ((end - addr) != P4D_SIZE)
-		return 0;
-
-	if (!IS_ALIGNED(addr, P4D_SIZE))
-		return 0;
-
-	if (!IS_ALIGNED(phys_addr, P4D_SIZE))
-		return 0;
-
-	if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
-		return 0;
-
-	return p4d_set_huge(p4d, phys_addr, prot);
-}
-
-static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			unsigned int max_page_shift, pgtbl_mod_mask *mask)
-{
-	p4d_t *p4d;
-	unsigned long next;
-
-	p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
-	if (!p4d)
-		return -ENOMEM;
-	do {
-		next = p4d_addr_end(addr, end);
-
-		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot, max_page_shift)) {
-			*mask |= PGTBL_P4D_MODIFIED;
-			continue;
-		}
-
-		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, max_page_shift, mask))
-			return -ENOMEM;
-	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
-	return 0;
-}
-
-static int vmap_range(unsigned long addr, unsigned long end,
-			phys_addr_t phys_addr, pgprot_t prot,
-			unsigned int max_page_shift)
-{
-	pgd_t *pgd;
-	unsigned long start;
-	unsigned long next;
-	int err;
-	pgtbl_mod_mask mask = 0;
-
-	might_sleep();
-	BUG_ON(addr >= end);
-
-	start = addr;
-	pgd = pgd_offset_k(addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, max_page_shift, &mask);
-		if (err)
-			break;
-	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
-
-	flush_cache_vmap(start, end);
-
-	if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
-		arch_sync_kernel_mappings(start, end);
-
-	return err;
-}
-
 int ioremap_page_range(unsigned long addr,
 		       unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 42326dbffaf0..2f236aeeac24 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -68,6 +68,202 @@ static void free_work(struct work_struct *w)
 }
 
 /*** Page table manipulation functions ***/
+static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			pgtbl_mod_mask *mask)
+{
+	pte_t *pte;
+	u64 pfn;
+
+	pfn = phys_addr >> PAGE_SHIFT;
+	pte = pte_alloc_kernel_track(pmd, addr, mask);
+	if (!pte)
+		return -ENOMEM;
+	do {
+		BUG_ON(!pte_none(*pte));
+		set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
+		pfn++;
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+	*mask |= PGTBL_PTE_MODIFIED;
+	return 0;
+}
+
+static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
+{
+	if (max_page_shift < PMD_SHIFT)
+		return 0;
+
+	if (!arch_vmap_pmd_supported(prot))
+		return 0;
+
+	if ((end - addr) != PMD_SIZE)
+		return 0;
+
+	if (!IS_ALIGNED(addr, PMD_SIZE))
+		return 0;
+
+	if (!IS_ALIGNED(phys_addr, PMD_SIZE))
+		return 0;
+
+	if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
+		return 0;
+
+	return pmd_set_huge(pmd, phys_addr, prot);
+}
+
+static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
+{
+	pmd_t *pmd;
+	unsigned long next;
+
+	pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
+	if (!pmd)
+		return -ENOMEM;
+	do {
+		next = pmd_addr_end(addr, end);
+
+		if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot, max_page_shift)) {
+			*mask |= PGTBL_PMD_MODIFIED;
+			continue;
+		}
+
+		if (vmap_pte_range(pmd, addr, next, phys_addr, prot, mask))
+			return -ENOMEM;
+	} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
+	return 0;
+}
+
+static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
+{
+	if (max_page_shift < PUD_SHIFT)
+		return 0;
+
+	if (!arch_vmap_pud_supported(prot))
+		return 0;
+
+	if ((end - addr) != PUD_SIZE)
+		return 0;
+
+	if (!IS_ALIGNED(addr, PUD_SIZE))
+		return 0;
+
+	if (!IS_ALIGNED(phys_addr, PUD_SIZE))
+		return 0;
+
+	if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
+		return 0;
+
+	return pud_set_huge(pud, phys_addr, prot);
+}
+
+static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
+{
+	pud_t *pud;
+	unsigned long next;
+
+	pud = pud_alloc_track(&init_mm, p4d, addr, mask);
+	if (!pud)
+		return -ENOMEM;
+	do {
+		next = pud_addr_end(addr, end);
+
+		if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot, max_page_shift)) {
+			*mask |= PGTBL_PUD_MODIFIED;
+			continue;
+		}
+
+		if (vmap_pmd_range(pud, addr, next, phys_addr, prot, max_page_shift, mask))
+			return -ENOMEM;
+	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
+	return 0;
+}
+
+static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
+{
+	if (max_page_shift < P4D_SHIFT)
+		return 0;
+
+	if (!arch_vmap_p4d_supported(prot))
+		return 0;
+
+	if ((end - addr) != P4D_SIZE)
+		return 0;
+
+	if (!IS_ALIGNED(addr, P4D_SIZE))
+		return 0;
+
+	if (!IS_ALIGNED(phys_addr, P4D_SIZE))
+		return 0;
+
+	if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
+		return 0;
+
+	return p4d_set_huge(p4d, phys_addr, prot);
+}
+
+static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift, pgtbl_mod_mask *mask)
+{
+	p4d_t *p4d;
+	unsigned long next;
+
+	p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
+	if (!p4d)
+		return -ENOMEM;
+	do {
+		next = p4d_addr_end(addr, end);
+
+		if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot, max_page_shift)) {
+			*mask |= PGTBL_P4D_MODIFIED;
+			continue;
+		}
+
+		if (vmap_pud_range(p4d, addr, next, phys_addr, prot, max_page_shift, mask))
+			return -ENOMEM;
+	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
+	return 0;
+}
+
+int vmap_range(unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
+{
+	pgd_t *pgd;
+	unsigned long start;
+	unsigned long next;
+	int err;
+	pgtbl_mod_mask mask = 0;
+
+	might_sleep();
+	BUG_ON(addr >= end);
+
+	start = addr;
+	pgd = pgd_offset_k(addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		err = vmap_p4d_range(pgd, addr, next, phys_addr, prot, max_page_shift, &mask);
+		if (err)
+			break;
+	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
+
+	flush_cache_vmap(start, end);
+
+	if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
+		arch_sync_kernel_mappings(start, end);
+
+	return err;
+}
 
 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			     pgtbl_mod_mask *mask)
-- 
2.23.0

[PATCH v9 10/12] mm/vmalloc: add vmap_range_noflush variant

[Nicholas Piggin]

As a side-effect, the order of flush_cache_vmap() and
arch_sync_kernel_mappings() calls are switched, but that now matches
the other callers in this file.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 mm/vmalloc.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 2f236aeeac24..ee9c3bee67f5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -235,7 +235,7 @@ static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 	return 0;
 }
 
-int vmap_range(unsigned long addr, unsigned long end,
+static int vmap_range_noflush(unsigned long addr, unsigned long end,
 			phys_addr_t phys_addr, pgprot_t prot,
 			unsigned int max_page_shift)
 {
@@ -257,14 +257,24 @@ int vmap_range(unsigned long addr, unsigned long end,
 			break;
 	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
 
-	flush_cache_vmap(start, end);
-
 	if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
 		arch_sync_kernel_mappings(start, end);
 
 	return err;
 }
 
+int vmap_range(unsigned long addr, unsigned long end,
+			phys_addr_t phys_addr, pgprot_t prot,
+			unsigned int max_page_shift)
+{
+	int err;
+
+	err = vmap_range_noflush(addr, end, phys_addr, prot, max_page_shift);
+	flush_cache_vmap(addr, end);
+
+	return err;
+}
+
 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			     pgtbl_mod_mask *mask)
 {
-- 
2.23.0

[PATCH v9 11/12] mm/vmalloc: Hugepage vmalloc mappings

[Nicholas Piggin]

Support huge page vmalloc mappings. Config option HAVE_ARCH_HUGE_VMALLOC
enables support on architectures that define HAVE_ARCH_HUGE_VMAP and
supports PMD sized vmap mappings.

vmalloc will attempt to allocate PMD-sized pages if allocating PMD size
or larger, and fall back to small pages if that was unsuccessful.

Architectures must ensure that any arch specific vmalloc allocations
that require PAGE_SIZE mappings (e.g., module allocations vs strict
module rwx) use the VM_NOHUGE flag to inhibit larger mappings.

When hugepage vmalloc mappings are enabled in the next patch, this
reduces TLB misses by nearly 30x on a `git diff` workload on a 2-node
POWER9 (59,800 -> 2,100) and reduces CPU cycles by 0.54%.

This can result in more internal fragmentation and memory overhead for a
given allocation, an option nohugevmalloc is added to disable at boot.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/Kconfig            |  10 +++
 include/linux/vmalloc.h |  18 ++++
 mm/page_alloc.c         |   5 +-
 mm/vmalloc.c            | 191 ++++++++++++++++++++++++++++++----------
 4 files changed, 178 insertions(+), 46 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 56b6ccc0e32d..d8f056fc27b4 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -662,6 +662,16 @@ config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 config HAVE_ARCH_HUGE_VMAP
 	bool
 
+config HAVE_ARCH_HUGE_VMALLOC
+	depends on HAVE_ARCH_HUGE_VMAP
+	bool
+	help
+	  Archs that select this would be capable of PMD-sized vmaps (i.e.,
+	  arch_vmap_pmd_supported() returns true), and they must make no
+	  assumptions that vmalloc memory is mapped with PAGE_SIZE ptes. The
+	  VM_NOHUGE flag can be used to prohibit arch-specific allocations from
+	  using hugepages to help with this (e.g., modules may require it).
+
 config ARCH_WANT_HUGE_PMD_SHARE
 	bool
 
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index a5ae791dc1e0..db018b531745 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -25,6 +25,7 @@ struct notifier_block;		/* in notifier.h */
 #define VM_NO_GUARD		0x00000040      /* don't add guard page */
 #define VM_KASAN		0x00000080      /* has allocated kasan shadow memory */
 #define VM_MAP_PUT_PAGES	0x00000100	/* put pages and free array in vfree */
+#define VM_NOHUGE		0x00000200	/* force PAGE_SIZE pte mapping */
 
 /*
  * VM_KASAN is used slighly differently depending on CONFIG_KASAN_VMALLOC.
@@ -59,6 +60,7 @@ struct vm_struct {
 	unsigned long		size;
 	unsigned long		flags;
 	struct page		**pages;
+	unsigned int		page_order;
 	unsigned int		nr_pages;
 	phys_addr_t		phys_addr;
 	const void		*caller;
@@ -196,6 +198,18 @@ static inline void set_vm_flush_reset_perms(void *addr)
 	if (vm)
 		vm->flags |= VM_FLUSH_RESET_PERMS;
 }
+
+static inline bool is_vm_area_hugepages(const void *addr)
+{
+	/*
+	 * This may not 100% tell if the area is mapped with > PAGE_SIZE
+	 * page table entries, if for some reason the architecture indicates
+	 * larger sizes are available but decides not to use them, nothing
+	 * prevents that. This only indicates the size of the physical page
+	 * allocated in the vmalloc layer.
+	 */
+	return (find_vm_area(addr)->page_order > 0);
+}
 #else
 static inline int
 map_kernel_range_noflush(unsigned long start, unsigned long size,
@@ -212,6 +226,10 @@ unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
 static inline void set_vm_flush_reset_perms(void *addr)
 {
 }
+static inline bool is_vm_area_hugepages(const void *addr)
+{
+	return false;
+}
 #endif
 
 /* for /dev/kmem */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index eaa227a479e4..d907da0ad349 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -70,6 +70,7 @@
 #include <linux/psi.h>
 #include <linux/padata.h>
 #include <linux/khugepaged.h>
+#include <linux/vmalloc.h>
 
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
@@ -8171,6 +8172,7 @@ void *__init alloc_large_system_hash(const char *tablename,
 	void *table = NULL;
 	gfp_t gfp_flags;
 	bool virt;
+	bool huge;
 
 	/* allow the kernel cmdline to have a say */
 	if (!numentries) {
@@ -8238,6 +8240,7 @@ void *__init alloc_large_system_hash(const char *tablename,
 		} else if (get_order(size) >= MAX_ORDER || hashdist) {
 			table = __vmalloc(size, gfp_flags);
 			virt = true;
+			huge = is_vm_area_hugepages(table);
 		} else {
 			/*
 			 * If bucketsize is not a power-of-two, we may free
@@ -8254,7 +8257,7 @@ void *__init alloc_large_system_hash(const char *tablename,
 
 	pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
 		tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
-		virt ? "vmalloc" : "linear");
+		virt ? (huge ? "vmalloc hugepage" : "vmalloc") : "linear");
 
 	if (_hash_shift)
 		*_hash_shift = log2qty;
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ee9c3bee67f5..3800380b474f 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -42,6 +42,19 @@
 #include "internal.h"
 #include "pgalloc-track.h"
 
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
+static bool __ro_after_init vmap_allow_huge = true;
+
+static int __init set_nohugevmalloc(char *str)
+{
+	vmap_allow_huge = false;
+	return 0;
+}
+early_param("nohugevmalloc", set_nohugevmalloc);
+#else /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */
+static const bool vmap_allow_huge = false;
+#endif	/* CONFIG_HAVE_ARCH_HUGE_VMALLOC */
+
 bool is_vmalloc_addr(const void *x)
 {
 	unsigned long addr = (unsigned long)x;
@@ -477,31 +490,12 @@ static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr,
 	return 0;
 }
 
-/**
- * map_kernel_range_noflush - map kernel VM area with the specified pages
- * @addr: start of the VM area to map
- * @size: size of the VM area to map
- * @prot: page protection flags to use
- * @pages: pages to map
- *
- * Map PFN_UP(@size) pages at @addr.  The VM area @addr and @size specify should
- * have been allocated using get_vm_area() and its friends.
- *
- * NOTE:
- * This function does NOT do any cache flushing.  The caller is responsible for
- * calling flush_cache_vmap() on to-be-mapped areas before calling this
- * function.
- *
- * RETURNS:
- * 0 on success, -errno on failure.
- */
-int map_kernel_range_noflush(unsigned long addr, unsigned long size,
-			     pgprot_t prot, struct page **pages)
+static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
+		pgprot_t prot, struct page **pages)
 {
 	unsigned long start = addr;
-	unsigned long end = addr + size;
-	unsigned long next;
 	pgd_t *pgd;
+	unsigned long next;
 	int err = 0;
 	int nr = 0;
 	pgtbl_mod_mask mask = 0;
@@ -523,6 +517,65 @@ int map_kernel_range_noflush(unsigned long addr, unsigned long size,
 	return 0;
 }
 
+static int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
+		pgprot_t prot, struct page **pages, unsigned int page_shift)
+{
+	unsigned int i, nr = (end - addr) >> PAGE_SHIFT;
+
+	WARN_ON(page_shift < PAGE_SHIFT);
+
+	if (page_shift == PAGE_SHIFT)
+		return vmap_small_pages_range_noflush(addr, end, prot, pages);
+
+	for (i = 0; i < nr; i += 1U << (page_shift - PAGE_SHIFT)) {
+		int err;
+
+		err = vmap_range_noflush(addr, addr + (1UL << page_shift),
+					__pa(page_address(pages[i])), prot,
+					page_shift);
+		if (err)
+			return err;
+
+		addr += 1UL << page_shift;
+	}
+
+	return 0;
+}
+
+static int vmap_pages_range(unsigned long addr, unsigned long end,
+		pgprot_t prot, struct page **pages, unsigned int page_shift)
+{
+	int err;
+
+	err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
+	flush_cache_vmap(addr, end);
+	return err;
+}
+
+/**
+ * map_kernel_range_noflush - map kernel VM area with the specified pages
+ * @addr: start of the VM area to map
+ * @size: size of the VM area to map
+ * @prot: page protection flags to use
+ * @pages: pages to map
+ *
+ * Map PFN_UP(@size) pages at @addr.  The VM area @addr and @size specify should
+ * have been allocated using get_vm_area() and its friends.
+ *
+ * NOTE:
+ * This function does NOT do any cache flushing.  The caller is responsible for
+ * calling flush_cache_vmap() on to-be-mapped areas before calling this
+ * function.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int map_kernel_range_noflush(unsigned long addr, unsigned long size,
+			     pgprot_t prot, struct page **pages)
+{
+	return vmap_pages_range_noflush(addr, addr + size, prot, pages, PAGE_SHIFT);
+}
+
 int map_kernel_range(unsigned long start, unsigned long size, pgprot_t prot,
 		struct page **pages)
 {
@@ -2400,6 +2453,7 @@ static inline void set_area_direct_map(const struct vm_struct *area,
 {
 	int i;
 
+	/* HUGE_VMALLOC passes small pages to set_direct_map */
 	for (i = 0; i < area->nr_pages; i++)
 		if (page_address(area->pages[i]))
 			set_direct_map(area->pages[i]);
@@ -2433,11 +2487,12 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
 	 * map. Find the start and end range of the direct mappings to make sure
 	 * the vm_unmap_aliases() flush includes the direct map.
 	 */
-	for (i = 0; i < area->nr_pages; i++) {
+	for (i = 0; i < area->nr_pages; i += 1U << area->page_order) {
 		unsigned long addr = (unsigned long)page_address(area->pages[i]);
 		if (addr) {
+			unsigned long page_size = PAGE_SIZE << area->page_order;
 			start = min(addr, start);
-			end = max(addr + PAGE_SIZE, end);
+			end = max(addr + page_size, end);
 			flush_dmap = 1;
 		}
 	}
@@ -2480,11 +2535,11 @@ static void __vunmap(const void *addr, int deallocate_pages)
 	if (deallocate_pages) {
 		int i;
 
-		for (i = 0; i < area->nr_pages; i++) {
+		for (i = 0; i < area->nr_pages; i += 1U << area->page_order) {
 			struct page *page = area->pages[i];
 
 			BUG_ON(!page);
-			__free_pages(page, 0);
+			__free_pages(page, area->page_order);
 		}
 		atomic_long_sub(area->nr_pages, &nr_vmalloc_pages);
 
@@ -2674,12 +2729,17 @@ EXPORT_SYMBOL_GPL(vmap_pfn);
 #endif /* CONFIG_VMAP_PFN */
 
 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
-				 pgprot_t prot, int node)
+				 pgprot_t prot, unsigned int page_shift,
+				 int node)
 {
 	const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
-	unsigned int nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
-	unsigned int array_size = nr_pages * sizeof(struct page *), i;
+	unsigned int page_order = page_shift - PAGE_SHIFT;
+	unsigned long addr = (unsigned long)area->addr;
+	unsigned long size = get_vm_area_size(area);
+	unsigned int nr_small_pages = size >> PAGE_SHIFT;
+	unsigned int array_size = nr_small_pages * sizeof(struct page *);
 	struct page **pages;
+	unsigned int i;
 
 	gfp_mask |= __GFP_NOWARN;
 	if (!(gfp_mask & (GFP_DMA | GFP_DMA32)))
@@ -2700,30 +2760,35 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	}
 
 	area->pages = pages;
-	area->nr_pages = nr_pages;
+	area->nr_pages = nr_small_pages;
+	area->page_order = page_order;
 
-	for (i = 0; i < area->nr_pages; i++) {
+	/*
+	 * Careful, we allocate and map page_order pages, but tracking is done
+	 * per PAGE_SIZE page so as to keep the vm_struct APIs independent of
+	 * the physical/mapped size.
+	 */
+	for (i = 0; i < area->nr_pages; i += 1U << page_order) {
 		struct page *page;
+		int p;
 
-		if (node == NUMA_NO_NODE)
-			page = alloc_page(gfp_mask);
-		else
-			page = alloc_pages_node(node, gfp_mask, 0);
-
+		page = alloc_pages_node(node, gfp_mask, page_order);
 		if (unlikely(!page)) {
 			/* Successfully allocated i pages, free them in __vfree() */
 			area->nr_pages = i;
 			atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
 			goto fail;
 		}
-		area->pages[i] = page;
+
+		for (p = 0; p < (1U << page_order); p++)
+			area->pages[i + p] = page + p;
+
 		if (gfpflags_allow_blocking(gfp_mask))
 			cond_resched();
 	}
 	atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
 
-	if (map_kernel_range((unsigned long)area->addr, get_vm_area_size(area),
-			prot, pages) < 0)
+	if (vmap_pages_range(addr, addr + size, prot, pages, page_shift) < 0)
 		goto fail;
 
 	return area->addr;
@@ -2731,7 +2796,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 fail:
 	warn_alloc(gfp_mask, NULL,
 			  "vmalloc: allocation failure, allocated %ld of %ld bytes",
-			  (area->nr_pages*PAGE_SIZE), area->size);
+			  (area->nr_pages*PAGE_SIZE), size);
 	__vfree(area->addr);
 	return NULL;
 }
@@ -2762,19 +2827,44 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
 	struct vm_struct *area;
 	void *addr;
 	unsigned long real_size = size;
+	unsigned long real_align = align;
+	unsigned int shift = PAGE_SHIFT;
 
-	size = PAGE_ALIGN(size);
 	if (!size || (size >> PAGE_SHIFT) > totalram_pages())
 		goto fail;
 
-	area = __get_vm_area_node(real_size, align, VM_ALLOC | VM_UNINITIALIZED |
+	if (vmap_allow_huge && !(vm_flags & VM_NOHUGE) &&
+			arch_vmap_pmd_supported(prot) &&
+			(pgprot_val(prot) == pgprot_val(PAGE_KERNEL))) {
+		unsigned long size_per_node;
+
+		/*
+		 * Try huge pages. Only try for PAGE_KERNEL allocations,
+		 * others like modules don't yet expect huge pages in
+		 * their allocations due to apply_to_page_range not
+		 * supporting them.
+		 */
+
+		size_per_node = size;
+		if (node == NUMA_NO_NODE)
+			size_per_node /= num_online_nodes();
+		if (size_per_node >= PMD_SIZE) {
+			shift = PMD_SHIFT;
+			align = max(real_align, 1UL << shift);
+			size = ALIGN(real_size, 1UL << shift);
+		}
+	}
+
+again:
+	size = PAGE_ALIGN(size);
+	area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED |
 				vm_flags, start, end, node, gfp_mask, caller);
 	if (!area)
 		goto fail;
 
-	addr = __vmalloc_area_node(area, gfp_mask, prot, node);
+	addr = __vmalloc_area_node(area, gfp_mask, prot, shift, node);
 	if (!addr)
-		return NULL;
+		goto fail;
 
 	/*
 	 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
@@ -2788,8 +2878,19 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
 	return addr;
 
 fail:
-	warn_alloc(gfp_mask, NULL,
+	if (shift > PAGE_SHIFT) {
+		free_vm_area(area);
+		shift = PAGE_SHIFT;
+		align = real_align;
+		size = real_size;
+		goto again;
+	}
+
+	if (!area) {
+		/* Warn for area allocation, page allocations already warn */
+		warn_alloc(gfp_mask, NULL,
 			  "vmalloc: allocation failure: %lu bytes", real_size);
+	}
 	return NULL;
 }
 
-- 
2.23.0

Re: [PATCH v9 11/12] mm/vmalloc: Hugepage vmalloc mappings

[Ding Tianhong]

> +again:
> +	size = PAGE_ALIGN(size);
> +	area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED |
>  				vm_flags, start, end, node, gfp_mask, caller);
>  	if (!area)
>  		goto fail;
>  
> -	addr = __vmalloc_area_node(area, gfp_mask, prot, node);
> +	addr = __vmalloc_area_node(area, gfp_mask, prot, shift, node);
>  	if (!addr)
> -		return NULL;
> +		goto fail;
>  
>  	/*
>  	 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
> @@ -2788,8 +2878,19 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
>  	return addr;
>  
>  fail:
> -	warn_alloc(gfp_mask, NULL,
> +	if (shift > PAGE_SHIFT) {
> +		free_vm_area(area);
> +		shift = PAGE_SHIFT;
> +		align = real_align;
> +		size = real_size;
> +		goto again;
> +	}
> +
Hi, Nicholas:

I met a problem like this:

[   67.103584] ------------[ cut here ]------------
[   67.103884] kernel BUG at vmalloc.c:2892!
[   67.104387] Internal error: Oops - BUG: 0 [#1] SMP
[   67.104942] Process insmod (pid: 1161, stack limit = 0x(____ptrval____))
[   67.105356] CPU: 2 PID: 1161 Comm: insmod Tainted: G           O      4.19.95+ #9
[   67.105702] Hardware name: linux,dummy-virt (DT)
[   67.106006] pstate: a0000005 (NzCv daif -PAN -UAO)
[   67.106285] pc : free_vm_area+0x78/0x80
[   67.106549] lr : free_vm_area+0x58/0x80

it looks like when __vmalloc_area_node failed, the area is already released, and the free_vm_area
will release the vm area again, so trigger the problem.

3405         ret = remove_vm_area(area->addr);
3406         BUG_ON(ret != area);
3407         kfree(area);


Ding
> +	if (!area) {
> +		/* Warn for area allocation, page allocations already warn */
> +		warn_alloc(gfp_mask, NULL,
>  			  "vmalloc: allocation failure: %lu bytes", real_size);
> +	}
>  	return NULL;
>  }
>  
> 

[PATCH v9 12/12] powerpc/64s/radix: Enable huge vmalloc mappings

[Nicholas Piggin]

Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 Documentation/admin-guide/kernel-parameters.txt |  2 ++
 arch/powerpc/Kconfig                            |  1 +
 arch/powerpc/kernel/module.c                    | 13 +++++++++++--
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 44fde25bb221..3538c750c583 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3220,6 +3220,8 @@
 
 	nohugeiomap	[KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
 
+	nohugevmalloc	[PPC] Disable kernel huge vmalloc mappings.
+
 	nosmt		[KNL,S390] Disable symmetric multithreading (SMT).
 			Equivalent to smt=1.
 
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e9f13fe08492..ae10381dd324 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -178,6 +178,7 @@ config PPC
 	select GENERIC_TIME_VSYSCALL
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_HUGE_VMAP		if PPC_BOOK3S_64 && PPC_RADIX_MMU
+	select HAVE_ARCH_HUGE_VMALLOC		if HAVE_ARCH_HUGE_VMAP
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_KASAN			if PPC32 && PPC_PAGE_SHIFT <= 14
 	select HAVE_ARCH_KASAN_VMALLOC		if PPC32 && PPC_PAGE_SHIFT <= 14
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index a211b0253cdb..bc2695eeeb4c 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -92,8 +92,17 @@ void *module_alloc(unsigned long size)
 {
 	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
 
-	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, GFP_KERNEL,
-				    PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
+	/*
+	 * Don't do huge page allocations for modules yet until more testing
+	 * is done. STRICT_MODULE_RWX may require extra work to support this
+	 * too.
+	 */
+
+	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
+				    GFP_KERNEL,
+				    PAGE_KERNEL_EXEC,
+				    VM_NOHUGE | VM_FLUSH_RESET_PERMS,
+				    NUMA_NO_NODE,
 				    __builtin_return_address(0));
 }
 #endif
-- 
2.23.0