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Subject[PATCH v10 17/26] mm/mmap: Add shadow stack pages to memory accounting
Date
Account shadow stack pages to stack memory.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
v10:
- Use arch_shadow_stack_mapping() to make meaning clear.

v8:
- Change shadow stake pages from data_vm to stack_vm.

arch/x86/mm/pgtable.c | 7 +++++++
include/asm-generic/pgtable.h | 11 +++++++++++
mm/mmap.c | 5 +++++
3 files changed, 23 insertions(+)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index aa4d396ff98d..f384e0314ba7 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -890,3 +890,10 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)

#endif /* CONFIG_X86_64 */
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+
+#ifdef CONFIG_ARCH_HAS_SHADOW_STACK
+bool arch_shadow_stack_mapping(vm_flags_t vm_flags)
+{
+ return (vm_flags & VM_SHSTK);
+}
+#endif
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 2c3875724809..dbd415ab7dd8 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1215,6 +1215,17 @@ static inline pmd_t arch_maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma
#endif /* CONFIG_ARCH_MAYBE_MKWRITE */
#endif /* CONFIG_MMU */

+#ifdef CONFIG_MMU
+#ifdef CONFIG_ARCH_HAS_SHADOW_STACK
+bool arch_shadow_stack_mapping(vm_flags_t vm_flags);
+#else
+static inline bool arch_shadow_stack_mapping(vm_flags_t vm_flags)
+{
+ return false;
+}
+#endif /* CONFIG_ARCH_HAS_SHADOW_STACK */
+#endif /* CONFIG_MMU */
+
/*
* Architecture PAGE_KERNEL_* fallbacks
*
diff --git a/mm/mmap.c b/mm/mmap.c
index f609e9ec4a25..70d240b3559c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1681,6 +1681,9 @@ static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags)
if (file && is_file_hugepages(file))
return 0;

+ if (arch_shadow_stack_mapping(vm_flags))
+ return 1;
+
return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE;
}

@@ -3318,6 +3321,8 @@ void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages)
mm->stack_vm += npages;
else if (is_data_mapping(flags))
mm->data_vm += npages;
+ else if (arch_shadow_stack_mapping(flags))
+ mm->stack_vm += npages;
}

static vm_fault_t special_mapping_fault(struct vm_fault *vmf);
--
2.21.0
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