The patch titled
Subject: mm/x86: add missing pud helpers
has been added to the -mm mm-unstable branch. Its filename is
mm-x86-add-missing-pud-helpers.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-x86-add-missing-pud-helpers.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/x86: add missing pud helpers
Date: Wed, 7 Aug 2024 15:48:10 -0400
These new helpers will be needed for pud entry updates soon. Introduce
these helpers by referencing the pmd ones. Namely:
- pudp_invalidate()
- pud_modify()
Link: https://lkml.kernel.org/r/20240807194812.819412-7-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@xxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: James Houghton <jthoughton@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/pgtable.h | 55 ++++++++++++++++++++++++++-----
arch/x86/mm/pgtable.c | 12 ++++++
2 files changed, 59 insertions(+), 8 deletions(-)
--- a/arch/x86/include/asm/pgtable.h~mm-x86-add-missing-pud-helpers
+++ a/arch/x86/include/asm/pgtable.h
@@ -787,6 +787,12 @@ static inline pmd_t pmd_mkinvalid(pmd_t
__pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
}
+static inline pud_t pud_mkinvalid(pud_t pud)
+{
+ return pfn_pud(pud_pfn(pud),
+ __pgprot(pud_flags(pud) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
+}
+
static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask);
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
@@ -834,14 +840,8 @@ static inline pmd_t pmd_modify(pmd_t pmd
pmd_result = __pmd(val);
/*
- * To avoid creating Write=0,Dirty=1 PMDs, pte_modify() needs to avoid:
- * 1. Marking Write=0 PMDs Dirty=1
- * 2. Marking Dirty=1 PMDs Write=0
- *
- * The first case cannot happen because the _PAGE_CHG_MASK will filter
- * out any Dirty bit passed in newprot. Handle the second case by
- * going through the mksaveddirty exercise. Only do this if the old
- * value was Write=1 to avoid doing this on Shadow Stack PTEs.
+ * Avoid creating shadow stack PMD by accident. See comment in
+ * pte_modify().
*/
if (oldval & _PAGE_RW)
pmd_result = pmd_mksaveddirty(pmd_result);
@@ -851,6 +851,29 @@ static inline pmd_t pmd_modify(pmd_t pmd
return pmd_result;
}
+static inline pud_t pud_modify(pud_t pud, pgprot_t newprot)
+{
+ pudval_t val = pud_val(pud), oldval = val;
+ pud_t pud_result;
+
+ val &= _HPAGE_CHG_MASK;
+ val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK;
+ val = flip_protnone_guard(oldval, val, PHYSICAL_PUD_PAGE_MASK);
+
+ pud_result = __pud(val);
+
+ /*
+ * Avoid creating shadow stack PUD by accident. See comment in
+ * pte_modify().
+ */
+ if (oldval & _PAGE_RW)
+ pud_result = pud_mksaveddirty(pud_result);
+ else
+ pud_result = pud_clear_saveddirty(pud_result);
+
+ return pud_result;
+}
+
/*
* mprotect needs to preserve PAT and encryption bits when updating
* vm_page_prot
@@ -1389,10 +1412,26 @@ static inline pmd_t pmdp_establish(struc
}
#endif
+static inline pud_t pudp_establish(struct vm_area_struct *vma,
+ unsigned long address, pud_t *pudp, pud_t pud)
+{
+ page_table_check_pud_set(vma->vm_mm, pudp, pud);
+ if (IS_ENABLED(CONFIG_SMP)) {
+ return xchg(pudp, pud);
+ } else {
+ pud_t old = *pudp;
+ WRITE_ONCE(*pudp, pud);
+ return old;
+ }
+}
+
#define __HAVE_ARCH_PMDP_INVALIDATE_AD
extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp);
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+ pud_t *pudp);
+
/*
* Page table pages are page-aligned. The lower half of the top
* level is used for userspace and the top half for the kernel.
--- a/arch/x86/mm/pgtable.c~mm-x86-add-missing-pud-helpers
+++ a/arch/x86/mm/pgtable.c
@@ -641,6 +641,18 @@ pmd_t pmdp_invalidate_ad(struct vm_area_
}
#endif
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
+ defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+ pud_t *pudp)
+{
+ VM_WARN_ON_ONCE(!pud_present(*pudp));
+ pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
+ flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
+ return old;
+}
+#endif
+
/**
* reserve_top_address - reserves a hole in the top of kernel address space
* @reserve - size of hole to reserve
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-dax-dump-start-address-in-fault-handler.patch
mm-mprotect-push-mmu-notifier-to-puds.patch
mm-powerpc-add-missing-pud-helpers.patch
mm-x86-make-pud_leaf-only-care-about-pse-bit.patch
mm-x86-arch_check_zapped_pud.patch
mm-x86-add-missing-pud-helpers.patch
mm-mprotect-fix-dax-pud-handlings.patch
