From 3a6455d56bd7c4cfb1ea35ddae052943065e338e Mon Sep 17 00:00:00 2001 From: "Lorenzo Stoakes (Oracle)" Date: Fri, 20 Mar 2026 19:38:34 +0000 Subject: mm: convert do_brk_flags() to use vma_flags_t In order to be able to do this, we need to change VM_DATA_DEFAULT_FLAGS and friends and update the architecture-specific definitions also. We then have to update some KSM logic to handle VMA flags, and introduce VMA_STACK_FLAGS to define the vma_flags_t equivalent of VM_STACK_FLAGS. We also introduce two helper functions for use during the time we are converting legacy flags to vma_flags_t values - vma_flags_to_legacy() and legacy_to_vma_flags(). This enables us to iteratively make changes to break these changes up into separate parts. We use these explicitly here to keep VM_STACK_FLAGS around for certain users which need to maintain the legacy vm_flags_t values for the time being. We are no longer able to rely on the simple VM_xxx being set to zero if the feature is not enabled, so in the case of VM_DROPPABLE we introduce VMA_DROPPABLE as the vma_flags_t equivalent, which is set to EMPTY_VMA_FLAGS if the droppable flag is not available. While we're here, we make the description of do_brk_flags() into a kdoc comment, as it almost was already. We use vma_flags_to_legacy() to not need to update the vm_get_page_prot() logic as this time. Note that in create_init_stack_vma() we have to replace the BUILD_BUG_ON() with a VM_WARN_ON_ONCE() as the tested values are no longer build time available. We also update mprotect_fixup() to use VMA flags where possible, though we have to live with a little duplication between vm_flags_t and vma_flags_t values for the time being until further conversions are made. While we're here, update VM_SPECIAL to be defined in terms of VMA_SPECIAL_FLAGS now we have vma_flags_to_legacy(). Finally, we update the VMA tests to reflect these changes. Link: https://lkml.kernel.org/r/d02e3e45d9a33d7904b149f5604904089fd640ae.1774034900.git.ljs@kernel.org Signed-off-by: Lorenzo Stoakes (Oracle) Acked-by: Paul Moore [SELinux] Acked-by: Vlastimil Babka (SUSE) Cc: Albert Ou Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Al Viro Cc: Anton Ivanov Cc: "Borislav Petkov (AMD)" Cc: Catalin Marinas Cc: Chengming Zhou Cc: Christian Borntraeger Cc: Christian Brauner Cc: David Hildenbrand Cc: Dinh Nguyen Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Huacai Chen Cc: Ingo Molnar Cc: Jan Kara Cc: Jann Horn Cc: Johannes Berg Cc: Kees Cook Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Ondrej Mosnacek Cc: Palmer Dabbelt Cc: Pedro Falcato Cc: Richard Weinberger Cc: Russell King Cc: Stephen Smalley Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Bogendoerfer Cc: Vasily Gorbik Cc: Vineet Gupta Cc: WANG Xuerui Cc: Will Deacon Cc: xu xin Signed-off-by: Andrew Morton --- include/linux/ksm.h | 10 +++++----- include/linux/mm.h | 49 ++++++++++++++++++++++++++++++------------------- 2 files changed, 35 insertions(+), 24 deletions(-) (limited to 'include/linux') diff --git a/include/linux/ksm.h b/include/linux/ksm.h index c982694c987b..d39d0d5483a2 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -17,8 +17,8 @@ #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, vm_flags_t *vm_flags); -vm_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, - vm_flags_t vm_flags); +vma_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file, + vma_flags_t vma_flags); int ksm_enable_merge_any(struct mm_struct *mm); int ksm_disable_merge_any(struct mm_struct *mm); int ksm_disable(struct mm_struct *mm); @@ -103,10 +103,10 @@ bool ksm_process_mergeable(struct mm_struct *mm); #else /* !CONFIG_KSM */ -static inline vm_flags_t ksm_vma_flags(struct mm_struct *mm, - const struct file *file, vm_flags_t vm_flags) +static inline vma_flags_t ksm_vma_flags(struct mm_struct *mm, + const struct file *file, vma_flags_t vma_flags) { - return vm_flags; + return vma_flags; } static inline int ksm_disable(struct mm_struct *mm) diff --git a/include/linux/mm.h b/include/linux/mm.h index de72382efac2..4042a584671e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -346,9 +346,9 @@ enum { * if KVM does not lock down the memory type. */ DECLARE_VMA_BIT(ALLOW_ANY_UNCACHED, 39), -#ifdef CONFIG_PPC32 +#if defined(CONFIG_PPC32) DECLARE_VMA_BIT_ALIAS(DROPPABLE, ARCH_1), -#else +#elif defined(CONFIG_64BIT) DECLARE_VMA_BIT(DROPPABLE, 40), #endif DECLARE_VMA_BIT(UFFD_MINOR, 41), @@ -503,31 +503,42 @@ enum { #endif #if defined(CONFIG_64BIT) || defined(CONFIG_PPC32) #define VM_DROPPABLE INIT_VM_FLAG(DROPPABLE) +#define VMA_DROPPABLE mk_vma_flags(VMA_DROPPABLE_BIT) #else #define VM_DROPPABLE VM_NONE +#define VMA_DROPPABLE EMPTY_VMA_FLAGS #endif /* Bits set in the VMA until the stack is in its final location */ #define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEQ_READ | VM_STACK_EARLY) -#define TASK_EXEC ((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0) +#define TASK_EXEC_BIT ((current->personality & READ_IMPLIES_EXEC) ? \ + VMA_EXEC_BIT : VMA_READ_BIT) /* Common data flag combinations */ -#define VM_DATA_FLAGS_TSK_EXEC (VM_READ | VM_WRITE | TASK_EXEC | \ - VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC) -#define VM_DATA_FLAGS_NON_EXEC (VM_READ | VM_WRITE | VM_MAYREAD | \ - VM_MAYWRITE | VM_MAYEXEC) -#define VM_DATA_FLAGS_EXEC (VM_READ | VM_WRITE | VM_EXEC | \ - VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC) - -#ifndef VM_DATA_DEFAULT_FLAGS /* arch can override this */ -#define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_EXEC +#define VMA_DATA_FLAGS_TSK_EXEC mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, \ + TASK_EXEC_BIT, VMA_MAYREAD_BIT, VMA_MAYWRITE_BIT, \ + VMA_MAYEXEC_BIT) +#define VMA_DATA_FLAGS_NON_EXEC mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, \ + VMA_MAYREAD_BIT, VMA_MAYWRITE_BIT, VMA_MAYEXEC_BIT) +#define VMA_DATA_FLAGS_EXEC mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, \ + VMA_EXEC_BIT, VMA_MAYREAD_BIT, VMA_MAYWRITE_BIT, \ + VMA_MAYEXEC_BIT) + +#ifndef VMA_DATA_DEFAULT_FLAGS /* arch can override this */ +#define VMA_DATA_DEFAULT_FLAGS VMA_DATA_FLAGS_EXEC #endif -#ifndef VM_STACK_DEFAULT_FLAGS /* arch can override this */ -#define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS +#ifndef VMA_STACK_DEFAULT_FLAGS /* arch can override this */ +#define VMA_STACK_DEFAULT_FLAGS VMA_DATA_DEFAULT_FLAGS #endif +#define VMA_STACK_FLAGS append_vma_flags(VMA_STACK_DEFAULT_FLAGS, \ + VMA_STACK_BIT, VMA_ACCOUNT_BIT) + +/* Temporary until VMA flags conversion complete. */ +#define VM_STACK_FLAGS vma_flags_to_legacy(VMA_STACK_FLAGS) + #define VM_STARTGAP_FLAGS (VM_GROWSDOWN | VM_SHADOW_STACK) #ifdef CONFIG_MSEAL_SYSTEM_MAPPINGS @@ -536,8 +547,6 @@ enum { #define VM_SEALED_SYSMAP VM_NONE #endif -#define VM_STACK_FLAGS (VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT) - /* VMA basic access permission flags */ #define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC) #define VMA_ACCESS_FLAGS mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, VMA_EXEC_BIT) @@ -545,7 +554,10 @@ enum { /* * Special vmas that are non-mergable, non-mlock()able. */ -#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP) + +#define VMA_SPECIAL_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_DONTEXPAND_BIT, \ + VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT) +#define VM_SPECIAL vma_flags_to_legacy(VMA_SPECIAL_FLAGS) /* * Physically remapped pages are special. Tell the @@ -1407,7 +1419,7 @@ static __always_inline void vma_desc_set_flags_mask(struct vm_area_desc *desc, * vm_area_desc object describing a proposed VMA, e.g.: * * vma_desc_set_flags(desc, VMA_IO_BIT, VMA_PFNMAP_BIT, VMA_DONTEXPAND_BIT, - * VMA_DONTDUMP_BIT); + * VMA_DONTDUMP_BIT); */ #define vma_desc_set_flags(desc, ...) \ vma_desc_set_flags_mask(desc, mk_vma_flags(__VA_ARGS__)) @@ -4045,7 +4057,6 @@ extern int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file); extern struct file *get_mm_exe_file(struct mm_struct *mm); extern struct file *get_task_exe_file(struct task_struct *task); -extern bool may_expand_vm(struct mm_struct *, vm_flags_t, unsigned long npages); extern void vm_stat_account(struct mm_struct *, vm_flags_t, long npages); extern bool vma_is_special_mapping(const struct vm_area_struct *vma, -- cgit v1.2.3