From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7667D38CFF6; Wed, 13 May 2026 14:54:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778684076; cv=none; b=jGnLOcYhcgsRWjO7C6tAsVzxvi6MtMpJ6qgGI6//MD5hHf4HyC7y/MngmFJ6Ns41fWzRA6ePnXa4QQKsfaJiyZmajXhSENDaXZHQot2z/7fhdfyrh1LPPL6AopoOd0NykDc3Gci+A7G1HMp4U5FB6duaGc0UY5USAmt9+/1uv14= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778684076; c=relaxed/simple; bh=5tb/dZ3Z6XZ9rdTRViFJg2CQhxIhIhB3K1EbtjSZ+/0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=OxQkraJwf4jPFkTw7+qyHUJjtGTqGeWEYSL7baFPWZP6bZwzTalY6FG47HNaFEPWuSROJV+Kd0Zo+Gj9Nl4aTSdgyEQlZnupj6wITiCfh06ZAnb4wgZBImuAnkku02n9nub5UX0C0XrYnF6+puVSRbq3GliCzgnjIfefBHoBduI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OvLTF6/v; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OvLTF6/v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48FC9C19425; Wed, 13 May 2026 14:54:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778684076; bh=5tb/dZ3Z6XZ9rdTRViFJg2CQhxIhIhB3K1EbtjSZ+/0=; h=From:To:Cc:Subject:Date:From; b=OvLTF6/v0D+Is1Oo2vvsUkztjB8o43huMqy8iw+pSIEJ/nvZeP4oZB7YNeLzpX70+ F6KHL8ycBfURSnQT1p+fKlIB9OhRQVTn0tCsXa1apa7oDIctXQWRwXvxjqjrRXnGVK vd0ARq2IWqI97wp/22xXUA4xRls5LUhWjIkH09oIc79WCYDerBL44nYC8NvA/NJ6ri F+QGxwMrRLrw+4UqlN3r2QqLBtZCTVNDdmCrzGaBuNlD8cL0XM2IFfnEbrmTW1Rw7d GJhSsAo2QS1ZHFIkt5/EhT5m/ZBORkFb5yljim2NIz9XpXL5HyJ43DPn1XUH7ViMLt BGE9bIg+4eV6w== From: Arnd Bergmann To: Will Deacon , Joerg Roedel , Miguel Ojeda , Andrew Morton , Thomas Gleixner , Nathan Chancellor Cc: Arnd Bergmann , linux-kbuild@vger.kernel.org, stable@vger.kernel.org, Robin Murphy , Kees Cook , linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH] [v2] iommu, debugobjects: avoid gcc-16.1 section mismatch warnings Date: Wed, 13 May 2026 16:53:54 +0200 Message-Id: <20260513145425.1579430-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnd Bergmann gcc-16 has gained some more advanced inter-procedual optimization techniques that enable it to inline the dummy_tlb_add_page() and dummy_tlb_flush() function pointers into a specialized version of __arm_v7s_unmap: WARNING: modpost: vmlinux: section mismatch in reference: __arm_v7s_unmap+0x2cc (section: .text) -> dummy_tlb_add_page (section: .init.text) ERROR: modpost: Section mismatches detected. >From what I can tell, the transformation is correct, as this is only called when __arm_v7s_unmap() is called from arm_v7s_do_selftests(), which is also __init. Since __arm_v7s_unmap() however is not __init, gcc cannot inline the inner function calls directly. In debug_objects_selftest(), the same thing happens. Both the caller and the leaf function are __init, but the IPA pulls it into a non-init one: WARNING: modpost: vmlinux: section mismatch in reference: lookup_object_or_alloc+0x7c (section: .text.lookup_object_or_alloc) -> is_static_object (section: .init.text) Marking the affected functions as not "__init" would reliably avoid this issue but is not a good solution because it removes an otherwise correct annotation. I tried marking the functions as 'noinline', but that ended up not covering all the affected configurations. With some more experimenting, I found that marking these functions as __attribute__((noipa)) is both logical and reliable. In order to keep the syntax readable, add a custom macro for this in include/linux/compiler_attributes.h next to other related macros and use it to annotate both files. Link: https://lore.kernel.org/all/abRB6g-48ZX6Yl2r@willie-the-truck/ Cc: Will Deacon Cc: Thomas Gleixner Cc: Andrew Morton Cc: Miguel Ojeda Cc: linux-kbuild@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann --- v2: I merged both patches into one, to simplify the dependency on the new compiler_attributes.h macro. --- drivers/iommu/io-pgtable-arm-v7s.c | 18 ++++++++++++------ include/linux/compiler_attributes.h | 11 +++++++++++ lib/debugobjects.c | 2 +- 3 files changed, 24 insertions(+), 7 deletions(-) diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c index 40e33257d3c2..1dbef8c55007 100644 --- a/drivers/iommu/io-pgtable-arm-v7s.c +++ b/drivers/iommu/io-pgtable-arm-v7s.c @@ -777,21 +777,27 @@ struct io_pgtable_init_fns io_pgtable_arm_v7s_init_fns = { static struct io_pgtable_cfg *cfg_cookie __initdata; -static void __init dummy_tlb_flush_all(void *cookie) +/* + * __noipa prevents gcc from turning indirect iommu_flush_ops calls + * into direct calls from a specialized __arm_v7s_unmap() that triggers + * a build time section mismatch assertion. + */ +static __noipa void __init dummy_tlb_flush_all(void *cookie) { WARN_ON(cookie != cfg_cookie); } -static void __init dummy_tlb_flush(unsigned long iova, size_t size, - size_t granule, void *cookie) +static __noipa void __init dummy_tlb_flush(unsigned long iova, size_t size, + size_t granule, void *cookie) { WARN_ON(cookie != cfg_cookie); WARN_ON(!(size & cfg_cookie->pgsize_bitmap)); } -static void __init dummy_tlb_add_page(struct iommu_iotlb_gather *gather, - unsigned long iova, size_t granule, - void *cookie) +static __noipa void __init dummy_tlb_add_page(struct iommu_iotlb_gather *gather, + unsigned long iova, + size_t granule, + void *cookie) { dummy_tlb_flush(iova, granule, granule, cookie); } diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index c16d4199bf92..836a50f5917a 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -396,6 +396,17 @@ # define __disable_sanitizer_instrumentation #endif +/* + * Optional: not supported by clang + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Attributes.html#index-noipa + */ +#if __has_attribute(noipa) +# define __noipa __attribute__((noipa)) +#else +# define __noipa +#endif + /* * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 12e2e42e6a31..c93b7ca3e1ab 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -1212,7 +1212,7 @@ struct self_test { static __initconst const struct debug_obj_descr descr_type_test; -static bool __init is_static_object(void *addr) +static __noipa bool __init is_static_object(void *addr) { struct self_test *obj = addr; -- 2.39.5