Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] x86: efi: avoid BUILD_BUG_ON() for non-constant p4d_index | Date | Thu, 7 Jan 2021 23:34:15 +0100 |
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From: Arnd Bergmann <arnd@arndb.de>
When 5-level page tables are enabled, clang triggers a BUILD_BUG_ON():
x86_64-linux-ld: arch/x86/platform/efi/efi_64.o: in function `efi_sync_low_kernel_mappings': efi_64.c:(.text+0x22c): undefined reference to `__compiletime_assert_354'
Use the same method as in commit c65e774fb3f6 ("x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable") and change it to MAYBE_BUILD_BUG_ON(), so it only triggers for constant input.
Link: https://github.com/ClangBuiltLinux/linux/issues/256 Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/x86/platform/efi/efi_64.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index e1e8d4e3a213..62bb1616b4a5 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -137,8 +137,8 @@ void efi_sync_low_kernel_mappings(void) * As with PGDs, we share all P4D entries apart from the one entry * that covers the EFI runtime mapping space. */ - BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END)); - BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK)); + MAYBE_BUILD_BUG_ON(p4d_index(EFI_VA_END) != p4d_index(MODULES_END)); + MAYBE_BUILD_BUG_ON((EFI_VA_START & P4D_MASK) != (EFI_VA_END & P4D_MASK)); pgd_efi = efi_pgd + pgd_index(EFI_VA_END); pgd_k = pgd_offset_k(EFI_VA_END); -- 2.29.2
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