percpu: add __alloc_size attributes for better bounds checking

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.

Note that due to the implementation of the percpu API, this is unlikely
to ever actually provide compile-time checking beyond very simple
non-SMP builds.  But, since they are technically allocators, mark them
as such.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>
Co-developed-by: Daniel Micay <[email protected]>
Signed-off-by: Daniel Micay <[email protected]>
Acked-by: Dennis Zhou <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Andy Whitcroft <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Dwaipayan Ray <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Lukas Bulwahn <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Alexandre Bounine <[email protected]>
Cc: Gustavo A. R. Silva <[email protected]>
Cc: Ira Weiny <[email protected]>
Cc: Jing Xiangfeng <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: kernel test robot <[email protected]>
Cc: Matt Porter <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Souptick Joarder <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 5e76af742c80..98a9371133f8 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -123,7 +123,7 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
 				pcpu_fc_populate_pte_fn_t populate_pte_fn);
 #endif
 
-extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
+extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1);
 extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
 extern bool is_kernel_percpu_address(unsigned long addr);
 
@@ -131,8 +131,8 @@ extern bool is_kernel_percpu_address(unsigned long addr);
 extern void __init setup_per_cpu_areas(void);
 #endif
 
-extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
-extern void __percpu *__alloc_percpu(size_t size, size_t align);
+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) __alloc_size(1);
 extern void free_percpu(void __percpu *__pdata);
 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);