On Sat, May 24, 2025 at 04:13:02PM +0530, Ritesh Harjani wrote:

Kees Cook [off-list ref] writes:

quoted

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
s390 this requires forcing a couple functions to be inline with
__always_inline.

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <redacted>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: "Aneesh Kumar K.V" <redacted>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <redacted>
---
 arch/powerpc/mm/book3s64/hash_utils.c    | 2 +-
 arch/powerpc/mm/book3s64/radix_pgtable.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 5158aefe4873..93f1e1eb5ea6 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c

@@ -409,7 +409,7 @@ static DEFINE_RAW_SPINLOCK(linear_map_kf_hash_lock);
 
 static phys_addr_t kfence_pool;
 
-static inline void hash_kfence_alloc_pool(void)
+static __always_inline void hash_kfence_alloc_pool(void)
 {
 	if (!kfence_early_init_enabled())
 		goto err;

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 9f764bc42b8c..3238e9ed46b5 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c

@@ -363,7 +363,7 @@ static int __meminit create_physical_mapping(unsigned long start,
 }
 
 #ifdef CONFIG_KFENCE
-static inline phys_addr_t alloc_kfence_pool(void)
+static __always_inline phys_addr_t alloc_kfence_pool(void)
 {
 	phys_addr_t kfence_pool;
 

I remember seeing a warning msg around .init.text section. Let me dig
that...

... Here it is: https://lore.kernel.org/oe-kbuild-all/202504190552.mnFGs5sj-lkp@intel.com/ (local)

I am not sure why it only complains for hash_debug_pagealloc_alloc_slots().
I believe there should me more functions to mark with __init here.
Anyways, here is the patch of what I had in mind.. I am not a compiler expert,
so please let me know your thoughts on this.

Yeah, this looks good. I'll snag your patch and drop mine. :)

-Kees

-- 
Kees Cook