On Thu, 12 Jan 2023 at 11:31, Alexander Potapenko <glider@xxxxxxxxxx> wrote: > > When building the kernel with W=1, the compiler reports numerous > warnings about the missing prototypes for KMSAN instrumentation hooks. > > Because these functions are not supposed to be called explicitly by the > kernel code (calls to them are emitted by the compiler), they do not > have to be declared in the headers. Instead, we add forward declarations > right before the definitions to silence the warnings produced by > -Wmissing-prototypes. > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Link: https://lore.kernel.org/lkml/202301020356.dFruA4I5-lkp@xxxxxxxxx/T/ > Reported-by: Vlastimil Babka <vbabka@xxxxxxx> > Suggested-by: Marco Elver <elver@xxxxxxxxxx> > Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> Reviewed-by: Marco Elver <elver@xxxxxxxxxx> > --- > mm/kmsan/instrumentation.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/mm/kmsan/instrumentation.c b/mm/kmsan/instrumentation.c > index 770fe02904f36..cf12e9616b243 100644 > --- a/mm/kmsan/instrumentation.c > +++ b/mm/kmsan/instrumentation.c > @@ -38,7 +38,15 @@ get_shadow_origin_ptr(void *addr, u64 size, bool store) > return ret; > } > > +/* > + * KMSAN instrumentation functions follow. They are not declared elsewhere in > + * the kernel code, so they are preceded by prototypes, to silence > + * -Wmissing-prototypes warnings. > + */ > + > /* Get shadow and origin pointers for a memory load with non-standard size. */ > +struct shadow_origin_ptr __msan_metadata_ptr_for_load_n(void *addr, > + uintptr_t size); > struct shadow_origin_ptr __msan_metadata_ptr_for_load_n(void *addr, > uintptr_t size) > { > @@ -47,6 +55,8 @@ struct shadow_origin_ptr __msan_metadata_ptr_for_load_n(void *addr, > EXPORT_SYMBOL(__msan_metadata_ptr_for_load_n); > > /* Get shadow and origin pointers for a memory store with non-standard size. */ > +struct shadow_origin_ptr __msan_metadata_ptr_for_store_n(void *addr, > + uintptr_t size); > struct shadow_origin_ptr __msan_metadata_ptr_for_store_n(void *addr, > uintptr_t size) > { > @@ -59,12 +69,16 @@ EXPORT_SYMBOL(__msan_metadata_ptr_for_store_n); > * with fixed size. > */ > #define DECLARE_METADATA_PTR_GETTER(size) \ > + struct shadow_origin_ptr __msan_metadata_ptr_for_load_##size( \ > + void *addr); \ > struct shadow_origin_ptr __msan_metadata_ptr_for_load_##size( \ > void *addr) \ > { \ > return get_shadow_origin_ptr(addr, size, /*store*/ false); \ > } \ > EXPORT_SYMBOL(__msan_metadata_ptr_for_load_##size); \ > + struct shadow_origin_ptr __msan_metadata_ptr_for_store_##size( \ > + void *addr); \ > struct shadow_origin_ptr __msan_metadata_ptr_for_store_##size( \ > void *addr) \ > { \ > @@ -86,6 +100,7 @@ DECLARE_METADATA_PTR_GETTER(8); > * entering or leaving IRQ. We omit the check for kmsan_in_runtime() to ensure > * the memory written to in these cases is also marked as initialized. > */ > +void __msan_instrument_asm_store(void *addr, uintptr_t size); > void __msan_instrument_asm_store(void *addr, uintptr_t size) > { > unsigned long ua_flags; > @@ -138,6 +153,7 @@ static inline void set_retval_metadata(u64 shadow, depot_stack_handle_t origin) > } > > /* Handle llvm.memmove intrinsic. */ > +void *__msan_memmove(void *dst, const void *src, uintptr_t n); > void *__msan_memmove(void *dst, const void *src, uintptr_t n) > { > depot_stack_handle_t origin; > @@ -162,6 +178,7 @@ void *__msan_memmove(void *dst, const void *src, uintptr_t n) > EXPORT_SYMBOL(__msan_memmove); > > /* Handle llvm.memcpy intrinsic. */ > +void *__msan_memcpy(void *dst, const void *src, uintptr_t n); > void *__msan_memcpy(void *dst, const void *src, uintptr_t n) > { > depot_stack_handle_t origin; > @@ -188,6 +205,7 @@ void *__msan_memcpy(void *dst, const void *src, uintptr_t n) > EXPORT_SYMBOL(__msan_memcpy); > > /* Handle llvm.memset intrinsic. */ > +void *__msan_memset(void *dst, int c, uintptr_t n); > void *__msan_memset(void *dst, int c, uintptr_t n) > { > depot_stack_handle_t origin; > @@ -217,6 +235,7 @@ EXPORT_SYMBOL(__msan_memset); > * uninitialized value to memory. When reporting an error, KMSAN unrolls and > * prints the whole chain of stores that preceded the use of this value. > */ > +depot_stack_handle_t __msan_chain_origin(depot_stack_handle_t origin); > depot_stack_handle_t __msan_chain_origin(depot_stack_handle_t origin) > { > depot_stack_handle_t ret = 0; > @@ -237,6 +256,7 @@ depot_stack_handle_t __msan_chain_origin(depot_stack_handle_t origin) > EXPORT_SYMBOL(__msan_chain_origin); > > /* Poison a local variable when entering a function. */ > +void __msan_poison_alloca(void *address, uintptr_t size, char *descr); > void __msan_poison_alloca(void *address, uintptr_t size, char *descr) > { > depot_stack_handle_t handle; > @@ -272,6 +292,7 @@ void __msan_poison_alloca(void *address, uintptr_t size, char *descr) > EXPORT_SYMBOL(__msan_poison_alloca); > > /* Unpoison a local variable. */ > +void __msan_unpoison_alloca(void *address, uintptr_t size); > void __msan_unpoison_alloca(void *address, uintptr_t size) > { > if (!kmsan_enabled || kmsan_in_runtime()) > @@ -287,6 +308,7 @@ EXPORT_SYMBOL(__msan_unpoison_alloca); > * Report that an uninitialized value with the given origin was used in a way > * that constituted undefined behavior. > */ > +void __msan_warning(u32 origin); > void __msan_warning(u32 origin) > { > if (!kmsan_enabled || kmsan_in_runtime()) > @@ -303,6 +325,7 @@ EXPORT_SYMBOL(__msan_warning); > * At the beginning of an instrumented function, obtain the pointer to > * `struct kmsan_context_state` holding the metadata for function parameters. > */ > +struct kmsan_context_state *__msan_get_context_state(void); > struct kmsan_context_state *__msan_get_context_state(void) > { > return &kmsan_get_context()->cstate; > -- > 2.39.0.314.g84b9a713c41-goog >
