From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E4BEC74A5B for ; Thu, 16 Mar 2023 14:15:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 61856900003; Thu, 16 Mar 2023 10:15:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5A217900002; Thu, 16 Mar 2023 10:15:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 41A9E900003; Thu, 16 Mar 2023 10:15:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 2B713900002 for ; Thu, 16 Mar 2023 10:15:35 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id DF23E80B39 for ; Thu, 16 Mar 2023 14:15:34 +0000 (UTC) X-FDA: 80574959388.12.1927233 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf22.hostedemail.com (Postfix) with ESMTP id 96BE4C000B for ; Thu, 16 Mar 2023 14:15:28 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf22.hostedemail.com: domain of wangkefeng.wang@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=wangkefeng.wang@huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1678976132; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ITp1vHSci2s5kqwS5Dp8A5D8uw63JhX4AO9+qtEWxPc=; b=RNoJ7KOym6J058AnegBsbzTq0BCUgkIMiGhYya6CE/LQSR9RIgCg2Pm3GAo5dVjEf2p/k9 RcBLs1J2kYV3iTaRUppACjkChlJ/KoD7LQQJMUzq8d4cSdRmqSdaKcRYTwiMeOy++grKLK 323wkAdOk0Zq1+d8QZVNOs/cLLy68jw= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf22.hostedemail.com: domain of wangkefeng.wang@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=wangkefeng.wang@huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1678976132; a=rsa-sha256; cv=none; b=0DJQpTq1c/PAADzblAx3tmFNkNYJTn1gTZyqrjzWF3gB9UJZtuxUAniTuxsBPHJmxMLJty ouLvLh+Zz49JrMaa6FWR1ILF5OEohakOtGfimz9USuAB2KRqAJCROf4o1bossGvby101qX fXjCTGbJDFUXXbwnjIvbsWaTfcRYFpo= Received: from dggpemm500001.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Pcq3l0qXmzHwj1; Thu, 16 Mar 2023 22:13:07 +0800 (CST) Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Thu, 16 Mar 2023 22:15:18 +0800 Message-ID: <8f064a51-723e-986e-be25-ec2929b685de@huawei.com> Date: Thu, 16 Mar 2023 22:15:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.5.1 Subject: Re: [PATCH v10] mm,kfence: decouple kfence from page granularity mapping judgement Content-Language: en-US To: Zhenhua Huang , , , , , , , , , , CC: , , , , , References: <1678969110-11941-1-git-send-email-quic_zhenhuah@quicinc.com> From: Kefeng Wang In-Reply-To: <1678969110-11941-1-git-send-email-quic_zhenhuah@quicinc.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 96BE4C000B X-Rspam-User: X-Stat-Signature: o1axw6jut7eyjg4pest6niep1f5oeuyq X-HE-Tag: 1678976128-38572 X-HE-Meta: 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 2Z8cECDt DsQSVMvIJ7DnXpOtPFVmjHf1Gff194ThrihDrkZFXZrzy9XmzWWKt0hFDo835SNFvAYqo1NbstVugH27sDJOjKwgiPswI3zcrVN+89t6T2QmHs97OgOCcK7cZRKsz3ocAp3fvnqN7McXfjCk4/YVaDiBtzvncBTY9ge8gxNeNVy0/AtyRN9zNRpsNV7NHDUrAXW4fN6OjNpX/tY8p3wsTGy/rquPM7RLqw767xr7xr21TxBhLM9tySbIdKzWe874EWfiv4C3qUtOjx8Gd1jFV0NdbS4C0HmdEU6vjtq7RUtAuu8lpD+PpaSj7m73HOw9pLQZt7hB70Acv0HXy5kkk/S7PN3eiRp1Wz18K 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: On 2023/3/16 20:18, Zhenhua Huang wrote: > Kfence only needs its pool to be mapped as page granularity, if it is > inited early. Previous judgement was a bit over protected. From [1], Mark > suggested to "just map the KFENCE region a page granularity". So I > decouple it from judgement and do page granularity mapping for kfence > pool only. Need to be noticed that late init of kfence pool still requires > page granularity mapping. > > Page granularity mapping in theory cost more(2M per 1GB) memory on arm64 > platform. Like what I've tested on QEMU(emulated 1GB RAM) with > gki_defconfig, also turning off rodata protection: > Before: > [root@liebao ]# cat /proc/meminfo > MemTotal: 999484 kB > After: > [root@liebao ]# cat /proc/meminfo > MemTotal: 1001480 kB > > To implement this, also relocate the kfence pool allocation before the > linear mapping setting up, arm64_kfence_alloc_pool is to allocate phys > addr, __kfence_pool is to be set after linear mapping set up. > A few little comments, > LINK: [1] https://lore.kernel.org/linux-arm-kernel/Y+IsdrvDNILA59UN@FVFF77S0Q05N/ > Suggested-by: Mark Rutland > Signed-off-by: Zhenhua Huang > --- > arch/arm64/include/asm/kfence.h | 10 +++++++ > arch/arm64/mm/mmu.c | 61 +++++++++++++++++++++++++++++++++++++++++ > arch/arm64/mm/pageattr.c | 7 +++-- > mm/kfence/core.c | 4 +++ > 4 files changed, 80 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h > index aa855c6..a81937f 100644 > --- a/arch/arm64/include/asm/kfence.h > +++ b/arch/arm64/include/asm/kfence.h > @@ -19,4 +19,14 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect) > return true; > } > > +#ifdef CONFIG_KFENCE > +extern bool kfence_early_init; > +static inline bool arm64_kfence_can_set_direct_map(void) > +{ > + return !kfence_early_init; > +} > +#else /* CONFIG_KFENCE */ > +static inline bool arm64_kfence_can_set_direct_map(void) { return false; } > +#endif /* CONFIG_KFENCE */ > + > #endif /* __ASM_KFENCE_H */ > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index ae25524d..aaf1801 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -24,6 +24,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -38,6 +39,7 @@ > #include > #include > #include > +#include > > #define NO_BLOCK_MAPPINGS BIT(0) > #define NO_CONT_MAPPINGS BIT(1) > @@ -521,12 +523,67 @@ static int __init enable_crash_mem_map(char *arg) > } > early_param("crashkernel", enable_crash_mem_map); > > +#ifdef CONFIG_KFENCE > + > +bool kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL; maybe add __ro_after_init > + > +/* early_param() will be parsed before map_mem() below. */ > +static int __init parse_kfence_early_init(char *arg) > +{ > + int val; > + > + if (get_option(&arg, &val)) > + kfence_early_init = !!val; > + return 0; > +} > +early_param("kfence.sample_interval", parse_kfence_early_init); > + > +static phys_addr_t arm64_kfence_alloc_pool(void) and __init > +{ > + phys_addr_t kfence_pool; > + > + if (!kfence_early_init) > + return 0; > + > + kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); > + if (!kfence_pool) { > + pr_err("failed to allocate kfence pool\n"); > + kfence_early_init = false; > + return 0; > + } > + > + /* Temporarily mark as NOMAP. */ > + memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); > + > + return kfence_pool; > +} > + > +static void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) Ditto. Reviewed-by: Kefeng Wang > +{ > + if (!kfence_pool) > + return; > + > + /* KFENCE pool needs page-level mapping. */ > + __map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE, > + pgprot_tagged(PAGE_KERNEL), > + NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); > + memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); > + __kfence_pool = phys_to_virt(kfence_pool); > +} > +#else /* CONFIG_KFENCE */ > + > +static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; } > +static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { } > + > +#endif /* CONFIG_KFENCE */ > + > static void __init map_mem(pgd_t *pgdp) > { > static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); > phys_addr_t kernel_start = __pa_symbol(_stext); > phys_addr_t kernel_end = __pa_symbol(__init_begin); > phys_addr_t start, end; > + phys_addr_t early_kfence_pool; > int flags = NO_EXEC_MAPPINGS; > u64 i; > > @@ -539,6 +596,8 @@ static void __init map_mem(pgd_t *pgdp) > */ > BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); > > + early_kfence_pool = arm64_kfence_alloc_pool(); > + > if (can_set_direct_map()) > flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; > > @@ -604,6 +663,8 @@ static void __init map_mem(pgd_t *pgdp) > } > } > #endif > + > + arm64_kfence_map_pool(early_kfence_pool, pgdp); > } > > void mark_rodata_ro(void) > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c > index debdecf..dd1291a 100644 > --- a/arch/arm64/mm/pageattr.c > +++ b/arch/arm64/mm/pageattr.c > @@ -11,6 +11,7 @@ > #include > #include > #include > +#include > > struct page_change_data { > pgprot_t set_mask; > @@ -22,12 +23,14 @@ bool rodata_full __ro_after_init = IS_ENABLED(CONFIG_RODATA_FULL_DEFAULT_ENABLED > bool can_set_direct_map(void) > { > /* > - * rodata_full, DEBUG_PAGEALLOC and KFENCE require linear map to be > + * rodata_full and DEBUG_PAGEALLOC 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. > */ > return (rodata_enabled && rodata_full) || debug_pagealloc_enabled() || > - IS_ENABLED(CONFIG_KFENCE); > + arm64_kfence_can_set_direct_map(); > } > > static int change_page_range(pte_t *ptep, unsigned long addr, void *data) > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index 1417888..bf2f194c 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -824,6 +824,10 @@ void __init kfence_alloc_pool(void) > if (!kfence_sample_interval) > return; > > + /* if the pool has already been initialized by arch, skip the below. */ > + if (__kfence_pool) > + return; > + > __kfence_pool = memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); > > if (!__kfence_pool)