[PATCH v16 17/26] mm/mmap: Add shadow stack pages to memory accounting
From: Yu-cheng Yu <hidden>
Date: 2020-12-09 22:28:41
Also in:
linux-arch, linux-doc, linux-mm, lkml
Subsystem:
memory management, memory management - core, memory mapping, the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
Account shadow stack pages to stack memory. Signed-off-by: Yu-cheng Yu <redacted> --- arch/x86/mm/pgtable.c | 7 +++++++ include/linux/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 a9666b64bc05..68e98f70298b 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c@@ -893,3 +893,10 @@ 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/linux/pgtable.h b/include/linux/pgtable.h
index f62b96d74689..42066a2c8a7b 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h@@ -1408,6 +1408,17 @@ 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 5c8b4485860d..c5e2c9569e41 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -1720,6 +1720,9 @@ 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; }
@@ -3389,6 +3392,8 @@ 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