+ powerpc-8xx-add-vmap_pte_set_huge.patch added to mm-new branch

+ powerpc-8xx-add-vmap_pte_set_huge.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: powerpc/8xx: add vmap_pte_set_huge()
has been added to the -mm mm-new branch.  Its filename is
     powerpc-8xx-add-vmap_pte_set_huge.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/powerpc-8xx-add-vmap_pte_set_huge.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Wen Jiang <jiangwen6@xiaomi.com>
Subject: powerpc/8xx: add vmap_pte_set_huge()
Date: Sat, 07 Nov 2026 21:49:45 +0800

vmap installs PTE-level block mappings (SZ_16K/SZ_512K on powerpc/8xx)
by reusing set_huge_pte_at(), a HugeTLB helper gated by
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.

Add vmap_pte_set_huge() to powerpc/8xx, next to the existing
pmd_clear_huge()/pud_clear_huge() in mm/nohash/8xx.c. It builds the huge
PTE and writes it into the backing cells directly, without going through
set_huge_pte_at(), so it does not depend on CONFIG_HUGETLB_PAGE.

No vmap_pte_clear_huge() is needed: 8xx does not implement
arch_vmap_pte_range_unmap_size(), so the vmap unmap path never takes the
PTE-clearing branch.

In practice PPC_8xx selects HUGETLBFS unconditionally, so
CONFIG_HUGETLB_PAGE=n does not occur there today; this is a decoupling
cleanup rather than a new configuration.

There is no caller yet: mm/vmalloc.c is converted later in this series,
once the generic fallbacks are in place.

Link: https://lore.kernel.org/20261107134953.748622-3-jiangwenxiaomi@gmail.com
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: <leo.yan@arm.com>
Cc: Xueyuan Chen <xueyuan.chen21@gmail.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Andrew Donnellan <andrew+kernel@donnellan.id.au>
Cc: Wen Jiang <jiangwenxiaomi@gmail.com>
---

 arch/powerpc/include/asm/nohash/32/pte-8xx.h |    4 ++
 arch/powerpc/mm/nohash/8xx.c                 |   29 +++++++++++++++++
 2 files changed, 33 insertions(+)

--- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h~powerpc-8xx-add-vmap_pte_set_huge
+++ a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -235,6 +235,10 @@ static inline pte_t ptep_get(pte_t *ptep
 }
 #endif /* CONFIG_PPC_16K_PAGES */
 
+#define __HAVE_ARCH_VMAP_PTE_SET_HUGE
+void vmap_pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
+		       pgprot_t prot, unsigned long size);
+
 #endif
 
 #endif /* __KERNEL__ */
--- a/arch/powerpc/mm/nohash/8xx.c~powerpc-8xx-add-vmap_pte_set_huge
+++ a/arch/powerpc/mm/nohash/8xx.c
@@ -220,3 +220,32 @@ int pmd_clear_huge(pmd_t *pmd)
 {
 	 return 0;
 }
+
+/*
+ * vmap PTE-level block mapping. Sets a present kernel mapping directly,
+ * so unlike set_huge_pte_at() it needs neither CONFIG_HUGETLB_PAGE nor
+ * set_pte_filter() (a no-op for non-exec kernel mappings).
+ */
+void vmap_pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
+		       pgprot_t prot, unsigned long size)
+{
+	pmd_t *pmdp = pmd_off(&init_mm, addr);
+	pte_t pte = pfn_pte(PHYS_PFN(phys), prot);
+	pte_basic_t val;
+	pte_basic_t *entry = (pte_basic_t *)ptep;
+	int num, i;
+
+	pte = arch_make_huge_pte(pte, ilog2(size), 0);
+	val = pte_val(pte);
+
+	/*
+	 * Make sure hardware valid bit is not set. We don't do
+	 * tlb flush for this update.
+	 */
+	VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
+
+	num = number_of_cells_per_pte(pmdp, val, 1);
+
+	for (i = 0; i < num; i++, entry++, val += SZ_4K)
+		*entry = val;
+}
_

Patches currently in -mm which might be from jiangwen6@xiaomi.com are

arm64-mm-add-vmap_pte_set_huge-and-vmap_pte_clear_huge.patch
powerpc-8xx-add-vmap_pte_set_huge.patch
mm-vmalloc-use-vmap_pte_set_huge-vmap_pte_clear_huge-for-pte-level-block-mappings.patch
arm64-hugetlb-drop-the-init_mm-special-case-in-clear_flush.patch
mm-vmalloc-extract-vmap_set_ptes-to-consolidate-pte-mapping-logic.patch
mm-vmalloc-extract-vm_shift-to-consolidate-mapping-shift-selection.patch