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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id s194sm14416197pfs.57.2021.03.15.11.02.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Mar 2021 11:02:35 -0700 (PDT) From: Kees Cook To: Thomas Gleixner Cc: Kees Cook , Alexander Potapenko , Elena Reshetova , x86@kernel.org, Andy Lutomirski , Peter Zijlstra , Catalin Marinas , Will Deacon , Mark Rutland , Alexander Popov , Ard Biesheuvel , Jann Horn , Vlastimil Babka , 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 v6 2/6] init_on_alloc: Optimize static branches Date: Mon, 15 Mar 2021 11:02:25 -0700 Message-Id: <20210315180229.1224655-3-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210315180229.1224655-1-keescook@chromium.org> References: <20210315180229.1224655-1-keescook@chromium.org> MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=d73e14f50f59a92ac8538519f3e1f53d503ab26d; i=7VrM8Pzr5MGi8vAaDOW4xeiDtVYbjHgJsdLlT/sxDXE=; m=9pRPoTwktIPBeIWxjZ3xtu7JAekgWFD5JAmIfxnzZpU=; p=kGv6Q+SMrU5E1IdQ/vRaEbpDt4x68fXZGP3gRBxoslM= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmBPoTQACgkQiXL039xtwCYmkw//V/q 8YDIGvlrMf++Qpx3Y4F3jp6BV9YPPaIeh+7wAqmOGLpfhHGIggCuroF6Bx+Pb+rJbjJa63cbQizhi k+AxuhTsUnZpfHDR4Q1TIjsYJAN8XBXR1HGAaLwnq/D20E+EJsPOMDCisEsVPuvQbJdxaW7qb0oDK vmDWKOZCcN7VIYqpXnqB897l8P5RcLTtv4l3yUs1mVosqpb+CNXMSPI1Csr3e8nrZPM5SuoYZakj2 i3gfACSgTGgzqo5KZvY58pagDyHUK7lufPiP9kwsnmq6Jv8OvlbkNQwwC8vzmek5lJ9rpju01wlDr O4a7cCdjmm2CjDMAI1maK25DDY0MkNzViwrAtSJ0g28yVrPq8OTQINu4J/oKsu8DOeU8dk+34adFn 5fSkkgS3r20gMPIrsVPDewIJBmOzWQAUbaFhoUucmBcOAHLPnmmTyOzcBqBgksXuOckNOZcwIUvys Mtb04OUCS3Pxzl1b3XcOLInfxgqm88Bre7PgJv5HvexCmdLHKJ6aCNojW9UP4qngdA/HgFkL0LTwU PwcmH+LmUx5Ofpm8QT/VEoUhjsA3j9ZHX/R7vfwe9w6Sl42G6IXNZr9Ft79uOnYTfh3rkH8ksvs/U Xmq1KzeG9cpSvVSK3U4JH8tziH45YgiOwYUOazJKUTgYCIyV6QPse1xpMvnH/cXs= X-Stat-Signature: 9ccqw1ej8u3nubkz96e4tjsn31pphcci X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 86C7D211F71F Received-SPF: none (chromium.org>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=mail-pl1-f170.google.com; client-ip=209.85.214.170 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615831357-982441 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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=3DX0DVwqLaHJTO6Jw7TGcMSm77GKHin= rd0m_6y0SzWOrFA@mail.gmail.com/ 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 pag= e *page, int numpages) { } static inline void kernel_unpoison_pages(struct page *page, int numpages= ) { } #endif =20 -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; } =20 -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); } =20 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; =20 int percpu_pagelist_fraction; gfp_t gfp_allowed_mask __read_mostly =3D 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); =20 -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); =20 static bool _init_on_alloc_enabled_early __read_mostly diff --git a/mm/slab.h b/mm/slab.h index 076582f58f68..b0977d525c06 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -601,7 +601,8 @@ static inline void cache_random_seq_destroy(struct km= em_cache *cachep) { } =20 static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cach= e *c) { - if (static_branch_unlikely(&init_on_alloc)) { + if (static_branch_maybe(CONFIG_INIT_ON_FREE_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 flag= s, struct kmem_cache *c) =20 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; --=20 2.25.1