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mm/x86: implement arch_check_zapped_pud()

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Introduce arch_check_zapped_pud() to sanity check shadow stack on PUD
zaps.  It has the same logic as the PMD helper.

One thing to mention is, it might be a good idea to use page_table_check
in the future for trapping wrong setups of shadow stack pgtable entries
[1].  That is left for the future as a separate effort.

[1] https://lore.kernel.org/all/59d518698f664e07c036a5098833d7b56b953305.camel@intel.com

Link: https://lkml.kernel.org/r/20240812181225.1360970-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Peter Xu 2024-08-12 14:12:23 -04:00 committed by Andrew Morton
parent 144bb0aee3
commit 1c399e74a9
4 changed files with 25 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/x86/include/asm/pgtable.h
View File

@ -174,6 +174,13 @@ static inline int pud_young(pud_t pud)
return pud_flags(pud) & _PAGE_ACCESSED;
}
static inline bool pud_shstk(pud_t pud)
{
return cpu_feature_enabled(X86_FEATURE_SHSTK) &&
(pud_flags(pud) & (_PAGE_RW | _PAGE_DIRTY | _PAGE_PSE)) ==
(_PAGE_DIRTY | _PAGE_PSE);
}
static inline int pte_write(pte_t pte)
{
/*
@ -1667,6 +1674,9 @@ void arch_check_zapped_pte(struct vm_area_struct *vma, pte_t pte);
#define arch_check_zapped_pmd arch_check_zapped_pmd
void arch_check_zapped_pmd(struct vm_area_struct *vma, pmd_t pmd);
#define arch_check_zapped_pud arch_check_zapped_pud
void arch_check_zapped_pud(struct vm_area_struct *vma, pud_t pud);
#ifdef CONFIG_XEN_PV
#define arch_has_hw_nonleaf_pmd_young arch_has_hw_nonleaf_pmd_young
static inline bool arch_has_hw_nonleaf_pmd_young(void)

6
arch/x86/mm/pgtable.c
View File

@ -926,3 +926,9 @@ void arch_check_zapped_pmd(struct vm_area_struct *vma, pmd_t pmd)
VM_WARN_ON_ONCE(!(vma->vm_flags & VM_SHADOW_STACK) &&
pmd_shstk(pmd));
}
void arch_check_zapped_pud(struct vm_area_struct *vma, pud_t pud)
{
/* See note in arch_check_zapped_pte() */
VM_WARN_ON_ONCE(!(vma->vm_flags & VM_SHADOW_STACK) && pud_shstk(pud));
}

6
include/linux/pgtable.h
View File

@ -447,6 +447,12 @@ static inline void arch_check_zapped_pmd(struct vm_area_struct *vma,
}
#endif
#ifndef arch_check_zapped_pud
static inline void arch_check_zapped_pud(struct vm_area_struct *vma, pud_t pud)
{
}
#endif
#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
unsigned long address,

4
mm/huge_memory.c
View File

@ -2283,12 +2283,14 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
pud_t *pud, unsigned long addr)
{
spinlock_t *ptl;
pud_t orig_pud;
ptl = __pud_trans_huge_lock(pud, vma);
if (!ptl)
return 0;
pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm);
orig_pud = pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm);
arch_check_zapped_pud(vma, orig_pud);
tlb_remove_pud_tlb_entry(tlb, pud, addr);
if (vma_is_special_huge(vma)) {
spin_unlock(ptl);