diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/util.c | 25 |
2 files changed, 27 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index abb4963c1f06..bb0cfe38ca19 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3903,6 +3903,8 @@ extern int vm_munmap(unsigned long, size_t); extern unsigned long __must_check vm_mmap(struct file *, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long); +extern unsigned long __must_check vm_mmap_shadow_stack(unsigned long addr, + unsigned long len, unsigned long flags); struct vm_unmapped_area_info { #define VM_UNMAPPED_AREA_TOPDOWN 1 diff --git a/mm/util.c b/mm/util.c index b05ab6f97e11..51f7f417e91f 100644 --- a/mm/util.c +++ b/mm/util.c @@ -618,6 +618,31 @@ unsigned long vm_mmap(struct file *file, unsigned long addr, } EXPORT_SYMBOL(vm_mmap); +#ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK +/* + * Perform a userland memory mapping for a shadow stack into the current + * process address space. This is intended to be used by architectures that + * support user shadow stacks. + */ +unsigned long vm_mmap_shadow_stack(unsigned long addr, unsigned long len, + unsigned long flags) +{ + struct mm_struct *mm = current->mm; + unsigned long ret, unused; + + flags |= MAP_ANONYMOUS | MAP_PRIVATE; + if (addr) + flags |= MAP_FIXED_NOREPLACE; + + mmap_write_lock(mm); + ret = do_mmap(NULL, addr, len, PROT_READ | PROT_WRITE, flags, + VM_SHADOW_STACK, 0, &unused, NULL); + mmap_write_unlock(mm); + + return ret; +} +#endif /* CONFIG_ARCH_HAS_USER_SHADOW_STACK */ + /** * __vmalloc_array - allocate memory for a virtually contiguous array. * @n: number of elements. |