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| author | Kees Cook <kees@kernel.org> | 2025-07-23 22:50:26 -0700 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2025-07-24 16:55:11 -0700 |
| commit | 8245d47cfaba8a38337a447230b4d01f9946f5e1 (patch) | |
| tree | 812c211e2c936af10a295d242b2488abdb144778 /include/linux/efi.h | |
| parent | 65c430906efffee9bd7551d474f01a6b1197df90 (diff) | |
| download | linux-next-8245d47cfaba8a38337a447230b4d01f9946f5e1.tar.gz linux-next-8245d47cfaba8a38337a447230b4d01f9946f5e1.zip | |
x86: Handle KCOV __init vs inline mismatches
GCC appears to have kind of fragile inlining heuristics, in the
sense that it can change whether or not it inlines something based on
optimizations. It looks like the kcov instrumentation being added (or in
this case, removed) from a function changes the optimization results,
and some functions marked "inline" are _not_ inlined. In that case,
we end up with __init code calling a function not marked __init, and we
get the build warnings I'm trying to eliminate in the coming patch that
adds __no_sanitize_coverage to __init functions:
WARNING: modpost: vmlinux: section mismatch in reference: xbc_exit+0x8 (section: .text.unlikely) -> _xbc_exit (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: real_mode_size_needed+0x15 (section: .text.unlikely) -> real_mode_blob_end (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference: __set_percpu_decrypted+0x16 (section: .text.unlikely) -> early_set_memory_decrypted (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: memblock_alloc_from+0x26 (section: .text.unlikely) -> memblock_alloc_try_nid (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: acpi_arch_set_root_pointer+0xc (section: .text.unlikely) -> x86_init (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference: acpi_arch_get_root_pointer+0x8 (section: .text.unlikely) -> x86_init (section: .init.data)
WARNING: modpost: vmlinux: section mismatch in reference: efi_config_table_is_usable+0x16 (section: .text.unlikely) -> xen_efi_config_table_is_usable (section: .init.text)
This problem is somewhat fragile (though using either __always_inline
or __init will deterministically solve it), but we've tripped over
this before with GCC and the solution has usually been to just use
__always_inline and move on.
For x86 this means forcing several functions to be inline with
__always_inline.
Link: https://lore.kernel.org/r/20250724055029.3623499-2-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Diffstat (limited to 'include/linux/efi.h')
| -rw-r--r-- | include/linux/efi.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/efi.h b/include/linux/efi.h index 7d63d1d75f22..e3776d9cad07 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1334,7 +1334,7 @@ struct linux_efi_initrd { bool xen_efi_config_table_is_usable(const efi_guid_t *guid, unsigned long table); -static inline +static __always_inline bool efi_config_table_is_usable(const efi_guid_t *guid, unsigned long table) { if (!IS_ENABLED(CONFIG_XEN_EFI)) |