Page Detective will use it to walk the kernel page table. Make this function accessible from modules, and also while here make walk_page_range() accessible from modules, so Page Detective could use it to walk user page tables.
Signed-off-by: Pasha Tatashin pasha.tatashin@soleen.com --- include/linux/pagewalk.h | 2 ++ mm/pagewalk.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+)
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h index f5eb5a32aeed..ff25374470f0 100644 --- a/include/linux/pagewalk.h +++ b/include/linux/pagewalk.h @@ -124,6 +124,8 @@ int walk_page_range_novma(struct mm_struct *mm, unsigned long start, int walk_page_range_vma(struct vm_area_struct *vma, unsigned long start, unsigned long end, const struct mm_walk_ops *ops, void *private); +int walk_page_range_kernel(unsigned long start, unsigned long end, + const struct mm_walk_ops *ops, void *private); int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, void *private); int walk_page_mapping(struct address_space *mapping, pgoff_t first_index, diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 5f9f01532e67..050790aeb15f 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -478,6 +478,7 @@ int walk_page_range(struct mm_struct *mm, unsigned long start, } while (start = next, start < end); return err; } +EXPORT_SYMBOL_GPL(walk_page_range);
/** * walk_page_range_novma - walk a range of pagetables not backed by a vma @@ -541,6 +542,37 @@ int walk_page_range_novma(struct mm_struct *mm, unsigned long start, return walk_pgd_range(start, end, &walk); }
+/** + * walk_page_range_kernel - walk a range of pagetables of kernel/init_mm + * @start: start address of the virtual address range + * @end: end address of the virtual address range + * @ops: operation to call during the walk + * @private: private data for callbacks' usage + * + * Similar to walk_page_range_novma() but specifically walks init_mm.pgd table. + * + * Note: This function takes two looks: get_online_mems(), and mmap_read, this + * is to prevent kernel page tables from being freed while walking. + */ +int walk_page_range_kernel(unsigned long start, unsigned long end, + const struct mm_walk_ops *ops, void *private) +{ + get_online_mems(); + if (mmap_read_lock_killable(&init_mm)) { + put_online_mems(); + return -EAGAIN; + } + + walk_page_range_novma(&init_mm, start, end, ops, + init_mm.pgd, private); + + mmap_read_unlock(&init_mm); + put_online_mems(); + + return 0; +} +EXPORT_SYMBOL_GPL(walk_page_range_kernel); + int walk_page_range_vma(struct vm_area_struct *vma, unsigned long start, unsigned long end, const struct mm_walk_ops *ops, void *private)