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Fri, 18 Sep 2026 06:19:04 -0700 (PDT) Date: Fri, 18 Sep 2026 14:16:55 +0100 In-Reply-To: <20260918131656.3710047-1-vdonnefort@google.com> Mime-Version: 1.0 References: <20260918131656.3710047-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog Message-ID: <20260918131656.3710047-4-vdonnefort@google.com> Subject: [PATCH v1 3/4] arm64: mm: Introduce linear_map_needs_set() helper From: Vincent Donnefort To: catalin.marinas@arm.com, will@kernel.org, rafael@kernel.org Cc: mark.rutland@arm.com, lenb@kernel.org, pavel@kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, thierry.reding@kernel.org, rppt@kernel.org, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260918_061907_060431_6CD2B2F5 X-CRM114-Status: GOOD ( 16.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org can_set_direct_map() is intended as an external query function, but is also being called internally by map_mem() to initialise linear_map_requires_bbml3, duplicating the feature checks already present in force_pte_mapping(). Factor the list of features that require modifying linear map attributes into a shared helper linear_map_needs_set(). Signed-off-by: Vincent Donnefort --- arch/arm64/include/asm/mmu.h | 1 + arch/arm64/mm/mmu.c | 22 ++++++++++++++++++++-- arch/arm64/mm/pageattr.c | 12 +----------- 3 files changed, 22 insertions(+), 13 deletions(-) diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 5e1211c540ab..12ed21e2d0d7 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -70,6 +70,7 @@ extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, pgprot_t prot, bool page_mappings_only); extern void *fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot); extern void mark_linear_text_alias_ro(void); +extern bool linear_map_needs_set(void); extern int split_kernel_leaf_mapping(unsigned long start, unsigned long end); extern void linear_map_maybe_split_to_ptes(void); diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 79d90226fd5d..c18ed601f0a8 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -776,6 +776,24 @@ static int split_kernel_leaf_mapping_locked(unsigned long addr) return ret; } +/* + * True if the linear map needs to be modified for one of the following + * features: + * + * rodata_full and DEBUG_PAGEALLOC need to protect/unprotect pages in + * the linear map. + * + * KFENCE pool needs to protect/unprotect pages in the linear map if + * initialized late. + * + * Realms need to mark pages shared/protected in the linear map. + */ +bool linear_map_needs_set(void) +{ + return rodata_full || debug_pagealloc_enabled() || + arm64_kfence_can_set_direct_map() || is_realm_world(); +} + static inline bool force_pte_mapping(void) { const bool bbml3 = system_capabilities_finalized() ? @@ -785,7 +803,7 @@ static inline bool force_pte_mapping(void) return true; if (bbml3) return false; - return rodata_full || arm64_kfence_can_set_direct_map() || is_realm_world(); + return linear_map_needs_set(); } static DEFINE_MUTEX(pgtable_split_lock); @@ -1203,7 +1221,7 @@ static void __init map_mem(void) arm64_kfence_map_pool(); - linear_map_requires_bbml3 = !force_pte_mapping() && can_set_direct_map(); + linear_map_requires_bbml3 = !force_pte_mapping() && linear_map_needs_set(); if (force_pte_mapping()) flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index bbe98ac9ad8c..c1ba74eb602f 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -89,17 +89,7 @@ bool rodata_full __ro_after_init = true; bool can_set_direct_map(void) { - /* - * rodata_full, DEBUG_PAGEALLOC and a Realm guest all require linear - * map to be mapped at page granularity, so that it is possible to - * protect/unprotect single pages. - * - * KFENCE pool requires page-granular mapping if initialized late. - * - * Realms need to make pages shared/protected at page granularity. - */ - return rodata_full || debug_pagealloc_enabled() || - arm64_kfence_can_set_direct_map() || is_realm_world(); + return linear_map_needs_set(); } static int update_range_prot(unsigned long start, unsigned long size, -- 2.55.0.1082.g2b9226bbc0-goog