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Diffstat (limited to 'include/linux/mman.h')
| -rw-r--r-- | include/linux/mman.h | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/include/linux/mman.h b/include/linux/mman.h new file mode 100644 index 000000000..40d94411d --- /dev/null +++ b/include/linux/mman.h @@ -0,0 +1,197 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_MMAN_H +#define _LINUX_MMAN_H + +#include <linux/mm.h> +#include <linux/percpu_counter.h> + +#include <linux/atomic.h> +#include <uapi/linux/mman.h> + +/* + * Arrange for legacy / undefined architecture specific flags to be + * ignored by mmap handling code. + */ +#ifndef MAP_32BIT +#define MAP_32BIT 0 +#endif +#ifndef MAP_ABOVE4G +#define MAP_ABOVE4G 0 +#endif +#ifndef MAP_HUGE_2MB +#define MAP_HUGE_2MB 0 +#endif +#ifndef MAP_HUGE_1GB +#define MAP_HUGE_1GB 0 +#endif +#ifndef MAP_UNINITIALIZED +#define MAP_UNINITIALIZED 0 +#endif +#ifndef MAP_SYNC +#define MAP_SYNC 0 +#endif + +/* + * The historical set of flags that all mmap implementations implicitly + * support when a ->mmap_validate() op is not provided in file_operations. + * + * MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the + * kernel. + */ +#define LEGACY_MAP_MASK (MAP_SHARED \ + | MAP_PRIVATE \ + | MAP_FIXED \ + | MAP_ANONYMOUS \ + | MAP_DENYWRITE \ + | MAP_EXECUTABLE \ + | MAP_UNINITIALIZED \ + | MAP_GROWSDOWN \ + | MAP_LOCKED \ + | MAP_NORESERVE \ + | MAP_POPULATE \ + | MAP_NONBLOCK \ + | MAP_STACK \ + | MAP_HUGETLB \ + | MAP_32BIT \ + | MAP_ABOVE4G \ + | MAP_HUGE_2MB \ + | MAP_HUGE_1GB) + +extern int sysctl_overcommit_memory; +extern int sysctl_overcommit_ratio; +extern unsigned long sysctl_overcommit_kbytes; +extern struct percpu_counter vm_committed_as; + +#ifdef CONFIG_SMP +extern s32 vm_committed_as_batch; +extern void mm_compute_batch(int overcommit_policy); +#else +#define vm_committed_as_batch 0 +static inline void mm_compute_batch(int overcommit_policy) +{ +} +#endif + +unsigned long vm_memory_committed(void); + +static inline void vm_acct_memory(long pages) +{ + percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch); +} + +static inline void vm_unacct_memory(long pages) +{ + vm_acct_memory(-pages); +} + +/* + * Allow architectures to handle additional protection and flag bits. The + * overriding macros must be defined in the arch-specific asm/mman.h file. + */ + +#ifndef arch_calc_vm_prot_bits +#define arch_calc_vm_prot_bits(prot, pkey) 0 +#endif + +#ifndef arch_calc_vm_flag_bits +#define arch_calc_vm_flag_bits(flags) 0 +#endif + +#ifndef arch_validate_prot +/* + * This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have + * already been masked out. + * + * Returns true if the prot flags are valid + */ +static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) +{ + return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0; +} +#define arch_validate_prot arch_validate_prot +#endif + +#ifndef arch_validate_flags +/* + * This is called from mmap() and mprotect() with the updated vma->vm_flags. + * + * Returns true if the VM_* flags are valid. + */ +static inline bool arch_validate_flags(unsigned long flags) +{ + return true; +} +#define arch_validate_flags arch_validate_flags +#endif + +/* + * Optimisation macro. It is equivalent to: + * (x & bit1) ? bit2 : 0 + * but this version is faster. + * ("bit1" and "bit2" must be single bits) + */ +#define _calc_vm_trans(x, bit1, bit2) \ + ((!(bit1) || !(bit2)) ? 0 : \ + ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \ + : ((x) & (bit1)) / ((bit1) / (bit2)))) + +/* + * Combine the mmap "prot" argument into "vm_flags" used internally. + */ +static inline unsigned long +calc_vm_prot_bits(unsigned long prot, unsigned long pkey) +{ + return _calc_vm_trans(prot, PROT_READ, VM_READ ) | + _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) | + _calc_vm_trans(prot, PROT_EXEC, VM_EXEC) | + arch_calc_vm_prot_bits(prot, pkey); +} + +/* + * Combine the mmap "flags" argument into "vm_flags" used internally. + */ +static inline unsigned long +calc_vm_flag_bits(unsigned long flags) +{ + return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | + _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | + _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | + arch_calc_vm_flag_bits(flags); +} + +unsigned long vm_commit_limit(void); + +/* + * Denies creating a writable executable mapping or gaining executable permissions. + * + * This denies the following: + * + * a) mmap(PROT_WRITE | PROT_EXEC) + * + * b) mmap(PROT_WRITE) + * mprotect(PROT_EXEC) + * + * c) mmap(PROT_WRITE) + * mprotect(PROT_READ) + * mprotect(PROT_EXEC) + * + * But allows the following: + * + * d) mmap(PROT_READ | PROT_EXEC) + * mmap(PROT_READ | PROT_EXEC | PROT_BTI) + */ +static inline bool map_deny_write_exec(struct vm_area_struct *vma, unsigned long vm_flags) +{ + if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags)) + return false; + + if ((vm_flags & VM_EXEC) && (vm_flags & VM_WRITE)) + return true; + + if (!(vma->vm_flags & VM_EXEC) && (vm_flags & VM_EXEC)) + return true; + + return false; +} + +#endif /* _LINUX_MMAN_H */ |