On Wed, 30 Aug 2023 at 19:51, Justin Stitt <justinstitt@xxxxxxxxxx> wrote: > > When building x86/defconfig with Clang-18 I encounter the following warnings: > | arch/x86/platform/efi/efi.c:934:23: warning: no previous extern declaration for non-static variable 'efi_attr_fw_vendor' [-Wmissing-variable-declarations] > | 934 | struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor); > | arch/x86/platform/efi/efi.c:935:23: warning: no previous extern declaration for non-static variable 'efi_attr_runtime' [-Wmissing-variable-declarations] > | 935 | struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime); > | arch/x86/platform/efi/efi.c:936:23: warning: no previous extern declaration for non-static variable 'efi_attr_config_table' [-Wmissing-variable-declarations] > | 936 | struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table); > > These symbols are declared extern in drivers/firmware/efi/efi.c. Move > the declarations to linux/efi.h to resolve these warnings. > > Also, trim a trailing space from efi_set_variable_t typedef. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1920 > Suggested-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> Thanks, I'll take this as a fix. > --- > Changes in v2: > - Don't use static. Instead move symbols to header file (thanks Ard) > - Remove duplicated warnings output from b4 (thanks Ard) > - Link to v1: https://lore.kernel.org/r/20230829-missingvardecl-efi-v1-1-13d055a55176@xxxxxxxxxx > --- > Note: build-tested. > > Also, a question: Why does the compiler warn at all? The extern > declarations _do_ exist as Ard points out [1]. > > [1]: https://lore.kernel.org/all/CAMj1kXE_xs+wWno4G4U+6CFCOwO7JWcmNv4et5=W=ZRrQatWnQ@xxxxxxxxxxxxxx/ Those declarations are not observed by the compiler when building .c files other than drivers/firmware/efi/efi.c, so they essentially don't exist when compiling arch/x86/platform/efi/efi.c. > --- > drivers/firmware/efi/efi.c | 3 --- > include/linux/efi.h | 6 +++++- > 2 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 1599f1176842..7b4e59ccf09e 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -161,9 +161,6 @@ static ssize_t fw_platform_size_show(struct kobject *kobj, > return sprintf(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32); > } > > -extern __weak struct kobj_attribute efi_attr_fw_vendor; > -extern __weak struct kobj_attribute efi_attr_runtime; > -extern __weak struct kobj_attribute efi_attr_config_table; > static struct kobj_attribute efi_attr_fw_platform_size = > __ATTR_RO(fw_platform_size); > > diff --git a/include/linux/efi.h b/include/linux/efi.h > index ab088c662e88..32f7ca60b0e9 100644 > --- a/include/linux/efi.h > +++ b/include/linux/efi.h > @@ -287,7 +287,7 @@ typedef efi_status_t efi_get_variable_t (efi_char16_t *name, efi_guid_t *vendor, > unsigned long *data_size, void *data); > typedef efi_status_t efi_get_next_variable_t (unsigned long *name_size, efi_char16_t *name, > efi_guid_t *vendor); > -typedef efi_status_t efi_set_variable_t (efi_char16_t *name, efi_guid_t *vendor, > +typedef efi_status_t efi_set_variable_t (efi_char16_t *name, efi_guid_t *vendor, > u32 attr, unsigned long data_size, > void *data); > typedef efi_status_t efi_get_next_high_mono_count_t (u32 *count); > @@ -632,6 +632,10 @@ typedef struct { > > extern unsigned long __ro_after_init efi_rng_seed; /* RNG Seed table */ > > +extern __weak struct kobj_attribute efi_attr_fw_vendor; > +extern __weak struct kobj_attribute efi_attr_runtime; > +extern __weak struct kobj_attribute efi_attr_config_table; > + > /* > * All runtime access to EFI goes through this structure: > */ > > --- > base-commit: 706a741595047797872e669b3101429ab8d378ef > change-id: 20230829-missingvardecl-efi-59306aacfed4 > > Best regards, > -- > Justin Stitt <justinstitt@xxxxxxxxxx> >
