When KCOV is enabled all functions get instrumented, unless
the __no_sanitize_coverage attribute is used. To prepare for
__no_sanitize_coverage being applied to __init functions, we
have to handle differences in how GCC's inline optimizations get
resolved. For arm64 this requires forcing one function to be inline
with __always_inline.

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Cc: James Morse <james.morse@arm.com>
Cc: Oza Pawandeep <quic_poza@quicinc.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
---
 arch/arm64/include/asm/acpi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index a407f9cd549e..c07a58b96329 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";
-- 
2.34.1

Hey Kees,

On Thu, Jul 17, 2025 at 04:25:11PM -0700, Kees Cook wrote:
> When KCOV is enabled all functions get instrumented, unless
> the __no_sanitize_coverage attribute is used. To prepare for
> __no_sanitize_coverage being applied to __init functions, we
> have to handle differences in how GCC's inline optimizations get
> resolved. For arm64 this requires forcing one function to be inline
> with __always_inline.

Please can you spell out the issue a bit more here? From the description
you've given, I can't figure out why acpi_get_enable_method() is the
only function that needs fixing up so I worry that this could be
fragile.

Thanks,

Will