[PATCH v29 19/32] mm/mmap: Add shadow stack pages to memory accounting
From: Yu-cheng Yu <hidden>
Date: 2021-08-20 18:21:05
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> Reviewed-by: Kirill A. Shutemov <redacted> Cc: Kees Cook <redacted> --- v26: - Remove redundant #ifdef CONFIG_MMU. v25: - Remove #ifdef CONFIG_ARCH_HAS_SHADOW_STACK for is_shadow_stack_mapping(). v24: - Change arch_shadow_stack_mapping() to is_shadow_stack_mapping(). - Change VM_SHSTK to VM_SHADOW_STACK. --- arch/x86/include/asm/pgtable.h | 3 +++ arch/x86/mm/pgtable.c | 5 +++++ include/linux/pgtable.h | 7 +++++++ mm/mmap.c | 5 +++++ 4 files changed, 20 insertions(+)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index bfe4ea2b652d..0983a91b464c 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h@@ -1638,6 +1638,9 @@ static inline bool arch_faults_on_old_pte(void) #define maybe_mkwrite maybe_mkwrite extern pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma); +#define is_shadow_stack_mapping is_shadow_stack_mapping +extern bool is_shadow_stack_mapping(vm_flags_t vm_flags); + #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_H */
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index c22c8e9c37e8..61a364b9ae0a 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c@@ -884,3 +884,8 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) #endif /* CONFIG_X86_64 */ #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ + +bool is_shadow_stack_mapping(vm_flags_t vm_flags) +{ + return vm_flags & VM_SHADOW_STACK; +}
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index e24d2c992b11..71aa63e2b014 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h@@ -1484,6 +1484,13 @@ static inline bool arch_has_pfn_modify_check(void) } #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */ +#ifndef is_shadow_stack_mapping +static inline bool is_shadow_stack_mapping(vm_flags_t vm_flags) +{ + return false; +} +#endif + /* * Architecture PAGE_KERNEL_* fallbacks *
diff --git a/mm/mmap.c b/mm/mmap.c
index ca54d36d203a..6be9ff4007ab 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -1721,6 +1721,9 @@ static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) if (file && is_file_hugepages(file)) return 0; + if (is_shadow_stack_mapping(vm_flags)) + return 1; + return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; }
@@ -3370,6 +3373,8 @@ 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 (is_shadow_stack_mapping(flags)) + mm->stack_vm += npages; } static vm_fault_t special_mapping_fault(struct vm_fault *vmf);
--
2.21.0