From: Kees Cook Date: Thu, 24 Jul 2025 05:50:25 +0000 (-0700) Subject: arm64: Handle KCOV __init vs inline mismatches X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=65c430906efffee9bd7551d474f01a6b1197df90;p=thirdparty%2Fkernel%2Flinux.git arm64: 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: acpi_get_enable_method+0x1c (section: .text.unlikely) -> acpi_psci_present (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 arm64 this requires forcing one ACPI function to be inlined with __always_inline. Link: https://lore.kernel.org/r/20250724055029.3623499-1-kees@kernel.org Signed-off-by: Kees Cook --- diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h index a407f9cd549ed..c07a58b96329d 100644 --- a/arch/arm64/include/asm/acpi.h +++ b/arch/arm64/include/asm/acpi.h @@ -150,7 +150,7 @@ acpi_set_mailbox_entry(int cpu, struct acpi_madt_generic_interrupt *processor) {} #endif -static inline const char *acpi_get_enable_method(int cpu) +static __always_inline const char *acpi_get_enable_method(int cpu) { if (acpi_psci_present()) return "psci";