From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0475B488766 for ; Mon, 21 Sep 2026 11:01:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789988464; cv=none; b=JLNF2E7PPFSc+A5zitD55TwouGQ/AL4kHAacHJF/34PDY0t8+9kfSRskCPsv3KtBoz9v79gMwvEqPwoE/XFC0skHf887NN46cAlFqe4GAy14Xx8DqI2v58tood7lPvpSZoGTYVa1Yd0vwSVeG3a0eKTKWn+GnnUlhP/UJWoKMiw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789988464; c=relaxed/simple; bh=nq6c2HIL7smpOLcesIc5VsHG9EFe4PxsntTqAaTUuBA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Uxcn1JQAeuJStJMN/WnMsgprH5g6ga+lOlc29j/n+DctIC6eQNjhSZ39wRlSJCGoEU7f8K30qRIIWCLEhz92fimw+PtHfIpsNo0uur8atk/1kNxNv2qLUtg1ic7qoowBunmQli19CFlHIRplJ9pNrLCoWH9D57+BcdQatISJeQ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=jo+/E8bc; arc=none smtp.client-ip=209.85.208.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="jo+/E8bc" Received: by mail-ed1-f69.google.com with SMTP id 4fb4d7f45d1cf-6aa1c4f3001so3829127a12.1 for ; Mon, 21 Sep 2026 04:01:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1789988459; x=1790593259; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=U06rcgIn0LVt5Do84ZIYuayP7YCGGpRPbIbmdcyZosY=; b=jo+/E8bcBPYZBTDMteRnOWdS8I4C3eHA5hUsw+cky15J/5G7BRyTzWo/J+M80/0w1R Ir287JkavtljC0NP2nhfWflwM72QexeqJPFmldGjE/bYXMs5CNzNCKovyjazcyvkT7Cc G+ttrAPZ/uGLV6Xu3G6ZnGIE0M9sMUg5geSo5RRE6Oz8RswsZnl2Z7Qnb1fkkhBdVXX/ 3p023XKdCkkQf3+r7UtWwijOtJxDm/JGjki15glYO1ZKf4jXtRc32kFWX/19GHbnTLJY 7kN3d2oEBZlK1tpu+8NYOv4oMJeYddorgGVWcB2BSSFTGNXpu7JtgKTq/8jyisAxsUf9 9j1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789988459; x=1790593259; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=U06rcgIn0LVt5Do84ZIYuayP7YCGGpRPbIbmdcyZosY=; b=wfjMowJTxKE9fg+KTP8ZDjWtJ3Hyt7UWMZO9R9dIkMB4i7xquzGcxnWk7pV1Yx+dQN zZo0jEVmcPktwQEZy8Tg8yi6ZPczjINN0pxk6x4J6cakYxulXKJdWlSLNOfSn/SJcNvI w+4lSjk6q0BbWAiV7LTPI4k7/kdrlJmba/JfzI9KyFUUo0lBx4YWNH7+dvW3pOdw385s enNpJ1SDpBIGRhD41LZMsRhwZ1Pe98NlCgWFJnINFkx4EXsY8QbVRtc2VOzYUMtDe/wA rA7Lh9qOB8aEm1jzDYgONB3/LnZXc3byBtgOppOJHUdRNF6yDQ8/xkrDLVLGthwQ6bnK yo9w== X-Forwarded-Encrypted: i=1; AKwUvByCQZkVOmg9ARQPK7q0EEtZDXvYfkNkL963N3+tZBmMuVsClBZY9RNRqZZm5udGv4uJKbdfBcslmPpd8lA=@vger.kernel.org X-Gm-Message-State: AFuF++nWIfIlavxW8b4ZoYZYkfksHsXqOwBKs+WHck351ZwKF+GbcNo8 7kGUEGzlblDRcY0sG/UjuYUQG3UPRg8f5QG2Vh24f6qzLgCdiQNjJwvNxAiESgVaRJJQSBgEyHM pJlDGYFJUutY4yBLPm6wtqg== X-Received: from edea12.prod.google.com ([2002:a05:6402:a18c:b0:6a6:1a9:f70f]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:23d5:b0:6a5:f814:2278 with SMTP id 4fb4d7f45d1cf-6aa577f5a1dmr7324139a12.2.1789988458556; Mon, 21 Sep 2026 04:00:58 -0700 (PDT) Date: Mon, 21 Sep 2026 12:00:44 +0100 In-Reply-To: <20260921110050.3977591-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260921110050.3977591-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog Message-ID: <20260921110050.3977591-3-vdonnefort@google.com> Subject: [PATCH v2 2/8] arm64: Introduce can_set_direct_map_range() From: Vincent Donnefort To: catalin.marinas@arm.com, will@kernel.org, rppt@kernel.org, akpm@linux-foundation.org, sudeep.holla@kernel.org, jenswi@kernel.org, robh@kernel.org Cc: mark.rutland@arm.com, sumit.garg@kernel.org, ardb@kernel.org, thierry.reding@kernel.org, david@kernel.org, danielmentz@google.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" For systems where can_set_direct_map() is false, it is still possible that a subregion of the direct map can be modified if it is mapped at the last-level. Add an implementation for can_set_direct_map_range(). It falls back to a page table walk to verify the mapping level if can_set_direct_map() is false. Signed-off-by: Vincent Donnefort --- arch/arm64/include/asm/set_memory.h | 3 ++ arch/arm64/mm/pageattr.c | 50 +++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h index 0091ba12200e..80bb94a340fd 100644 --- a/arch/arm64/include/asm/set_memory.h +++ b/arch/arm64/include/asm/set_memory.h @@ -9,6 +9,9 @@ bool can_set_direct_map(void); #define can_set_direct_map can_set_direct_map +bool can_set_direct_map_range(struct page *page, unsigned long numpages); +#define can_set_direct_map_range can_set_direct_map_range + int set_memory_valid(unsigned long addr, int numpages, int enable); int set_direct_map_invalid_noflush(struct page *page, unsigned int numpages); diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 132938b32eb1..5fcdb292905f 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -102,6 +102,56 @@ bool can_set_direct_map(void) arm64_kfence_can_set_direct_map() || is_realm_world(); } +static int can_set_direct_map_pud_entry(pud_t *pud, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + if (pud_leaf(pudp_get(pud))) + return -EINVAL; + + return 0; +} + +static int can_set_direct_map_pmd_entry(pmd_t *pmd, unsigned long addr, + unsigned long next, struct mm_walk *walk) +{ + if (pmd_leaf(pmdp_get(pmd))) + return -EINVAL; + + return 0; +} + +static int can_set_direct_map_pte_hole(unsigned long addr, unsigned long next, + int depth, struct mm_walk *walk) +{ + return -EINVAL; +} + +static const struct mm_walk_ops can_set_direct_map_ops = { + .pud_entry = can_set_direct_map_pud_entry, + .pmd_entry = can_set_direct_map_pmd_entry, + .pte_hole = can_set_direct_map_pte_hole, +}; + +bool can_set_direct_map_range(struct page *page, unsigned long numpages) +{ + unsigned long addr = (unsigned long)page_address(page); + unsigned long end = addr + numpages * PAGE_SIZE; + + if (can_set_direct_map()) + return true; + + if (!numpages) + return false; + + /* + * If !can_set_direct_map() then no one can split blocks and it is safe + * to walk the page-table lockless. + */ + return !walk_kernel_page_table_range_lockless(addr, end, + &can_set_direct_map_ops, + NULL, NULL); +} + static int update_range_prot(unsigned long start, unsigned long size, pgprot_t set_mask, pgprot_t clear_mask) { -- 2.55.0.1082.g2b9226bbc0-goog