Re: [PATCH v2 08/14] powerpc: Handle KCOV __init vs inline mismatches
From: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Date: 2025-05-24 11:19:16
Also in:
kvmarm, linux-arm-kernel, linux-doc, linux-efi, linux-hardening, linux-kbuild, linux-kselftest, linux-riscv, linux-s390, linux-security-module, lkml, llvm, sparclinux
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Kees Cook [off-list ref] writes:
quoted hunk ↗ jump to hunk
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. -ritesh From 59d64dc0014ccb4ae13ed08ab596738628ee23b1 Mon Sep 17 00:00:00 2001 Message-Id: [off-list ref] From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Date: Sat, 24 May 2025 16:14:08 +0530 Subject: [RFC] powerpc/mm/book3s64: Move few kfence & debug_pagealloc related calls to __init section Move few kfence and debug_pagealloc related functions in hash_utils.c and radix_pgtable.c to __init sections since these are only invoked once by an __init function during system initialization. i.e. - hash_debug_pagealloc_alloc_slots() - hash_kfence_alloc_pool() - hash_kfence_map_pool() The above 3 functions only gets called by __init htab_initialize(). - alloc_kfence_pool() - map_kfence_pool() The above 2 functions only gets called by __init radix_init_pgtable() This should also help fix warning msgs like:
quoted
WARNING: modpost: vmlinux: section mismatch in reference:
hash_debug_pagealloc_alloc_slots+0xb0 (section: .text) -> memblock_alloc_try_nid (section: .init.text) Reported-by: kernel test robot <redacted> Closes: https://lore.kernel.org/oe-kbuild-all/202504190552.mnFGs5sj-lkp@intel.com/ (local) Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> --- arch/powerpc/mm/book3s64/hash_utils.c | 6 +++--- arch/powerpc/mm/book3s64/radix_pgtable.c | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 5158aefe4873..4693c464fc5a 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c@@ -343,7 +343,7 @@ static inline bool hash_supports_debug_pagealloc(void) static u8 *linear_map_hash_slots; static unsigned long linear_map_hash_count; static DEFINE_RAW_SPINLOCK(linear_map_hash_lock); -static void hash_debug_pagealloc_alloc_slots(void) +static __init void hash_debug_pagealloc_alloc_slots(void) { if (!hash_supports_debug_pagealloc()) return;
@@ -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 __init void hash_kfence_alloc_pool(void) { if (!kfence_early_init_enabled()) goto err;
@@ -445,7 +445,7 @@ static inline void hash_kfence_alloc_pool(void) disable_kfence(); } -static inline void hash_kfence_map_pool(void) +static __init void hash_kfence_map_pool(void) { unsigned long kfence_pool_start, kfence_pool_end; unsigned long prot = pgprot_val(PAGE_KERNEL);
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 311e2112d782..ed226ee1569a 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 __init phys_addr_t alloc_kfence_pool(void) { phys_addr_t kfence_pool;
@@ -393,7 +393,7 @@ static inline phys_addr_t alloc_kfence_pool(void) return 0; } -static inline void map_kfence_pool(phys_addr_t kfence_pool) +static __init void map_kfence_pool(phys_addr_t kfence_pool) { if (!kfence_pool) return;
--
2.39.5