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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id n10sm6363653pjo.15.2021.04.01.16.23.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Apr 2021 16:23:51 -0700 (PDT) From: Kees Cook To: Thomas Gleixner Cc: Kees Cook , Alexander Potapenko , Vlastimil Babka , Elena Reshetova , x86@kernel.org, Andy Lutomirski , Peter Zijlstra , Catalin Marinas , Will Deacon , Mark Rutland , Alexander Popov , Ard Biesheuvel , Jann Horn , David Hildenbrand , Mike Rapoport , Andrew Morton , Jonathan Corbet , Randy Dunlap , kernel-hardening@lists.openwall.com, linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v10 2/6] init_on_alloc: Optimize static branches Date: Thu, 1 Apr 2021 16:23:43 -0700 Message-Id: <20210401232347.2791257-3-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210401232347.2791257-1-keescook@chromium.org> References: <20210401232347.2791257-1-keescook@chromium.org> MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=2f4b59272e09d0180c87e3d8378d95ea375990ec; i=7VrM8Pzr5MGi8vAaDOW4xeiDtVYbjHgJsdLlT/sxDXE=; m=OLLKLAHsfNT1d7+pflxMGJuAvSt8GZaetKIXzfk0ilc=; p=cKq4RSNZSRZ+ASTC07w37jURMQB1hxGsdgqU07adDH0= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmBmVgIACgkQiXL039xtwCaolw//ZCB Logxo6dDfC7433hgQdOfpHxCZxm/7rRC+f4joWq57/QBmOMjF3W073sD+R9vdDDCGsEiNo12ISjVa G+W/a9MmfBRhcDv4JpBDlh+Dw2dFA6Ix4+3Q8R9LCG2x8jUfAyp1yii+WOrGDhliFvL3Pd+RMa9W0 CnwK2yvrB108eSO8Ryikc91HMJnXqE5c4Lp1lW2CJhX2dqrqXZKMNp4o8bjv7UdsSEu/m9mJrpCho 6MeQreVX2J2AcCceALV2gngk2JdeOaO7oHnMm6Bi9NSFB2y6ZP5NK9PVE+28bRCgklWdAxJny2Biz Q+6qRteMMChf4RkN668cPz6+bAzfxX5UIxlU+SK3f0EnDFZFVBy62XJ+j2LoGUyMEU1m3ckvWOhxg Sh2NFhQF++EM5Dp6JmARfwgu1T0w/3Tr8AYh8sC31bdT2rLCwF24VQ+IMnewePUGopvjPDmww+t7X /I1dZST8HC21YoNAddrZtWfXnGe2BZr/j2QXHLUQRRBrw8ey4mj//A/iFrKjTOVftnP1PKOvIaEHP BjsAJO5EAzUSYilh+l8IxTyO/3ek103mtxJs+8/LlJwngI+OmtRSal6hnbv0deFcHZtYYWIi69MNG y3sfIi8Kj3wUjpeBziLMxM+cTUdsKW/aHPjRiOVT6W4tPmNgpwiG7OG3vLnPz98I= Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The state of CONFIG_INIT_ON_ALLOC_DEFAULT_ON (and ...ON_FREE...) did not change the assembly ordering of the static branches: they were always out of line. Use the new jump_label macros to check the CONFIG settings to default to the "expected" state, which slightly optimizes the resulting assembly code. Reviewed-by: Alexander Potapenko Link: https://lore.kernel.org/lkml/CAG_fn=X0DVwqLaHJTO6Jw7TGcMSm77GKHinrd0m_6y0SzWOrFA@mail.gmail.com/ Acked-by: Vlastimil Babka Link: https://lore.kernel.org/lkml/5d626b9b-5355-be94-e8e2-1be47f880f30@suse.cz Signed-off-by: Kees Cook --- include/linux/mm.h | 10 ++++++---- mm/page_alloc.c | 4 ++-- mm/slab.h | 6 ++++-- 3 files changed, 12 insertions(+), 8 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 77e64e3eac80..2ccd856ac0d1 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2871,18 +2871,20 @@ static inline void kernel_poison_pages(struct page *page, int numpages) { } static inline void kernel_unpoison_pages(struct page *page, int numpages) { } #endif -DECLARE_STATIC_KEY_FALSE(init_on_alloc); +DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc); static inline bool want_init_on_alloc(gfp_t flags) { - if (static_branch_unlikely(&init_on_alloc)) + if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, + &init_on_alloc)) return true; return flags & __GFP_ZERO; } -DECLARE_STATIC_KEY_FALSE(init_on_free); +DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free); static inline bool want_init_on_free(void) { - return static_branch_unlikely(&init_on_free); + return static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, + &init_on_free); } extern bool _debug_pagealloc_enabled_early; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3e4b29ee2b1e..267c04b8911d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -167,10 +167,10 @@ unsigned long totalcma_pages __read_mostly; int percpu_pagelist_fraction; gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; -DEFINE_STATIC_KEY_FALSE(init_on_alloc); +DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc); EXPORT_SYMBOL(init_on_alloc); -DEFINE_STATIC_KEY_FALSE(init_on_free); +DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free); EXPORT_SYMBOL(init_on_free); static bool _init_on_alloc_enabled_early __read_mostly diff --git a/mm/slab.h b/mm/slab.h index 076582f58f68..774c7221efdc 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -601,7 +601,8 @@ static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { } static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c) { - if (static_branch_unlikely(&init_on_alloc)) { + if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, + &init_on_alloc)) { if (c->ctor) return false; if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) @@ -613,7 +614,8 @@ static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c) static inline bool slab_want_init_on_free(struct kmem_cache *c) { - if (static_branch_unlikely(&init_on_free)) + if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, + &init_on_free)) return !(c->ctor || (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))); return false; -- 2.25.1