[PATCH v9 03/10] mm/vmalloc: use pte_set_huge()/pte_clear_huge() for PTE-level block mappings
From: Wen Jiang <hidden>
Date: 2026-09-23 06:29:29
Also in:
linux-arm-kernel, linux-mm, lkml
Subsystem:
memory management, memory management - core, the rest, vmalloc · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds, Uladzislau Rezki
vmap installs PTE-level block mappings by reusing set_huge_pte_at() and huge_ptep_get_and_clear() under #ifdef CONFIG_HUGETLB_PAGE. This makes the feature silently unavailable on CONFIG_HUGETLB_PAGE=n kernels and couples mm/vmalloc.c to HugeTLB internals it does not otherwise need. Now that arm64 and powerpc/8xx provide pte_set_huge() and pte_clear_huge(), add the generic fallbacks next to the existing pmd/pud_set_huge() family and convert vmap_pte_range() and vunmap_pte_range() to the new helpers. The CONFIG_HUGETLB_PAGE guards around the block-mapping paths are dropped, so PTE-level block mappings now also work on CONFIG_HUGETLB_PAGE=n kernels, and mm/vmalloc.c no longer includes <linux/hugetlb.h>. The fallbacks exist only to keep the build working on architectures without PTE-level block mapping support. They are unreachable there: the callers only run when arch_vmap_pte_range_map_size() or arch_vmap_pte_range_unmap_size() return a size other than PAGE_SIZE, which requires an arch implementation. BUILD_BUG() makes that explicit rather than silently doing nothing. Signed-off-by: Wen Jiang <redacted> --- include/linux/pgtable.h | 29 +++++++++++++++++++++++++++++ mm/vmalloc.c | 19 ++++++------------- 2 files changed, 35 insertions(+), 13 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8c093c119e5a8..a7fd51fec8a17 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h@@ -2204,6 +2204,35 @@ static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) } #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ +/* + * PTE-level block mappings for vmap. + * + * pte_set_huge() only has to be implemented by architectures whose + * arch_vmap_pte_range_map_size() can return a size other than PAGE_SIZE. + */ +#ifndef __HAVE_ARCH_PTE_SET_HUGE +static inline void pte_set_huge(pte_t *ptep, unsigned long addr, + phys_addr_t phys, pgprot_t prot, + unsigned long size) +{ + BUILD_BUG(); +} +#endif + +/* + * Likewise, pte_clear_huge() only has to be implemented by architectures + * whose arch_vmap_pte_range_unmap_size() can return a size other than + * PAGE_SIZE. + */ +#ifndef __HAVE_ARCH_PTE_CLEAR_HUGE +static inline pte_t pte_clear_huge(pte_t *ptep, unsigned long addr, + unsigned long size) +{ + BUILD_BUG(); + return __pte(0); +} +#endif + #ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE #ifdef CONFIG_TRANSPARENT_HUGEPAGE /*
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index bea9f76ed7e74..fb757d95bde25 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c@@ -38,7 +38,6 @@ #include <linux/rbtree_augmented.h> #include <linux/overflow.h> #include <linux/pgtable.h> -#include <linux/hugetlb.h> #include <linux/sched/mm.h> #include <asm/tlbflush.h> #include <asm/shmparam.h>
@@ -100,7 +99,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, pte_t *pte; u64 pfn; struct page *page; - unsigned long size = PAGE_SIZE; + unsigned long size; if (WARN_ON_ONCE(!PAGE_ALIGNED(end - addr))) return -EINVAL;
@@ -121,17 +120,12 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, BUG(); } -#ifdef CONFIG_HUGETLB_PAGE size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift); if (size != PAGE_SIZE) { - pte_t entry = pfn_pte(pfn, prot); - - entry = arch_make_huge_pte(entry, ilog2(size), 0); - set_huge_pte_at(&init_mm, addr, pte, entry, size); + pte_set_huge(pte, addr, PFN_PHYS(pfn), prot, size); pfn += PFN_DOWN(size); continue; } -#endif set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot)); pfn++; } while (pte += PFN_DOWN(size), addr += size, addr != end);
@@ -391,25 +385,24 @@ static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, { pte_t *pte; pte_t ptent; - unsigned long size = PAGE_SIZE; + unsigned long size; pte = pte_offset_kernel(pmd, addr); lazy_mmu_mode_enable(); do { -#ifdef CONFIG_HUGETLB_PAGE size = arch_vmap_pte_range_unmap_size(addr, pte); if (size != PAGE_SIZE) { if (WARN_ON(!IS_ALIGNED(addr, size))) { addr = ALIGN_DOWN(addr, size); pte = PTR_ALIGN_DOWN(pte, sizeof(*pte) * (size >> PAGE_SHIFT)); } - ptent = huge_ptep_get_and_clear(&init_mm, addr, pte, size); + ptent = pte_clear_huge(pte, addr, size); if (WARN_ON(end - addr < size)) size = end - addr; - } else -#endif + } else { ptent = ptep_get_and_clear(&init_mm, addr, pte); + } WARN_ON(!pte_none(ptent) && !pte_present(ptent)); } while (pte += (size >> PAGE_SHIFT), addr += size, addr != end);
--
2.34.1