[PATCH v2 6/7] percpu: Add __alloc_size attributes for better bounds checking

Kees Cook
2021-08-18T21:40:45Z

As already done in GrapheneOS, add the __alloc_size attribute for
appropriate percpu allocator interfaces, to provide additional hinting
for better bounds checking, assisting CONFIG_FORTIFY_SOURCE and other
compiler optimizations.

Co-developed-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: linux-mm@kvack.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
include/linux/percpu.h | 3 +++
1 file changed, 3 insertions(+)

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 5e76af742c80..119f41815b32 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -123,6 +123,7 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
pcpu_fc_populate_pte_fn_t populate_pte_fn);
#endif

+__alloc_size(1)
extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
extern bool is_kernel_percpu_address(unsigned long addr);
@@ -131,7 +132,9 @@ extern bool is_kernel_percpu_address(unsigned long addr);
extern void __init setup_per_cpu_areas(void);
#endif

+__alloc_size(1)
extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
+__alloc_size(1)
extern void __percpu *__alloc_percpu(size_t size, size_t align);
extern void free_percpu(void __percpu *__pdata);
extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
--
2.30.2