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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5219ACA0FF9 for ; Sat, 30 Aug 2025 00:47:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=wR8U3MqPvapfaeIOsKqNFOyhDMkaCgaH9/17xA/CDnw=; b=iFg73XSznsWgzMGQ6RAqoegwID D79Qoak1SgHimzioqtv621P+qqDn6BeeZmNV61AwOqf8rUoGXto/Ar5aLnXBmcDXytOPyuZccpVH2 RRD1nqbNRK30JQUKD7lGOK7W41jkaRGmCqjjyhm4xos3Ciyhg7eCiUWdUOJkByncmVIY2g3le3s4r bW7aMZFKmmOLKnNZOKvarRk2S/WwjV1H8yOeKkouWpNG8efSbS7xcZtQ4kyurJWJSw7rDWJmbAB0E WIG19GvqCopp69CVmhw+HpzJhHirhr1U/s4sitxYwZZVLQM92QJfouoadzbhHRcKsOuBf/WnEGngs f+oXsdiQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1us9k4-000000078qj-0cfR; Sat, 30 Aug 2025 00:46:52 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1us1cG-00000006Lkf-1Gsc for linux-arm-kernel@bombadil.infradead.org; Fri, 29 Aug 2025 16:06:16 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:Content-Type :In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID: Sender:Reply-To:Content-ID:Content-Description; bh=wR8U3MqPvapfaeIOsKqNFOyhDMkaCgaH9/17xA/CDnw=; b=iKw1lTPvWYtivscmSFq718bkLS jMsjEM1TQ9QJ1SU+ttl52mP7yxJjpxle6WupWS7vNl5p3XKRtOF8lFbsnAZ4Fk186qA69Vewqw+PI 4TahiwqkPuN8vf0PkNTWIkVuZ1ARz/0Y6jdpkJrrigZBjeL/2w+c4gFojYeiwzsX9yCHfHnkXapEf skGcvtoi5U+jyeoST/1rIatPX6tnf0pvTmLfou3n8fy+VByOMQUs9hUeVZGyJg0EfRo9oARQbC9+q mAmw4vLs7xFAoVj5Tx2KshtgZLwWB+foMLaMgXIarqmghZmU+gBmnDUu3ItPocHAfcg7/DK6NkXDy 0us52GxA==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1us1cC-00000003DCh-2ctb for linux-arm-kernel@lists.infradead.org; Fri, 29 Aug 2025 16:06:14 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C4E2D19F0; Fri, 29 Aug 2025 09:06:02 -0700 (PDT) Received: from [10.57.91.118] (unknown [10.57.91.118]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1FCB03F694; Fri, 29 Aug 2025 09:06:06 -0700 (PDT) Message-ID: <6b692d6c-2da6-413b-90fa-c1425c075628@arm.com> Date: Fri, 29 Aug 2025 17:06:05 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm64: mm: Fix CFI failure due to kpti_ng_pgd_alloc function signature Content-Language: en-GB To: Ard Biesheuvel , Kees Cook , Kevin Brodsky Cc: Catalin Marinas , Will Deacon , Oliver Upton , Anshuman Khandual , Yue Haibing , Mark Rutland , Marc Zyngier , Mark Brown , linux-arm-kernel@lists.infradead.org, Shameer Kolothum , Joey Gouly , Yeoreum Yun , James Morse , Hardevsinh Palaniya , Andrew Morton , Kevin Brodsky , David Hildenbrand , Zhenhua Huang , Lorenzo Stoakes , Dev Jain , Yicong Yang , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20250829154913.work.943-kees@kernel.org> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250829_170613_013034_1F53EFFB X-CRM114-Status: GOOD ( 17.81 ) 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 + Kevin Broadsky. On 29/08/2025 16:59, Ard Biesheuvel wrote: > On Fri, 29 Aug 2025 at 17:49, Kees Cook wrote: >> >> Seen during KPTI initialization: >> >> CFI failure at create_kpti_ng_temp_pgd+0x124/0xce8 (target: kpti_ng_pgd_alloc+0x0/0x14; expected type: 0xd61b88b6) >> >> The call site is alloc_init_pud() at arch/arm64/mm/mmu.c: >> >> pud_phys = pgtable_alloc(TABLE_PUD); >> >> alloc_init_pud() has the prototype: >> >> static void alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, >> phys_addr_t phys, pgprot_t prot, >> phys_addr_t (*pgtable_alloc)(enum pgtable_type), >> int flags) >> >> where the pgtable_alloc() prototype is declared. >> >> The target (kpti_ng_pgd_alloc) is used in arch/arm64/kernel/cpufeature.c: >> >> create_kpti_ng_temp_pgd(kpti_ng_temp_pgd, __pa(alloc), KPTI_NG_TEMP_VA, >> PAGE_SIZE, PAGE_KERNEL, kpti_ng_pgd_alloc, 0); >> >> which is an alias for __create_pgd_mapping_locked() with prototype: >> >> extern __alias(__create_pgd_mapping_locked) >> void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, >> unsigned long virt, >> phys_addr_t size, pgprot_t prot, >> phys_addr_t (*pgtable_alloc)(enum pgtable_type), >> int flags); >> >> __create_pgd_mapping_locked() passes the function pointer down: >> >> __create_pgd_mapping_locked() -> alloc_init_p4d() -> alloc_init_pud() >> >> But the target function (kpti_ng_pgd_alloc) has the wrong signature: >> >> static phys_addr_t __init kpti_ng_pgd_alloc(int shift); >> >> The "int" should be "enum pgtable_type". >> >> To make "enum pgtable_type" available to cpufeature.c, move >> enum pgtable_type definition from arch/arm64/mm/mmu.c to >> arch/arm64/include/asm/mmu.h. >> >> Adjust kpti_ng_pgd_alloc to use "enum pgtable_type" instead of "int". >> The function behavior remains identical (parameter is unused). >> >> Fixes: 47546a1912fc ("arm64: mm: install KPTI nG mappings with MMU enabled") > > Shouldn't this be > > Fixes: c64f46ee1377 ("arm64: mm: use enum to identify pgtable level > instead of *_SHIFT") You beat me to it; agreed. I've added Kevin, who made that change incase there are any other subtlety. > > >> Signed-off-by: Kees Cook > > Acked-by: Ard Biesheuvel Reviewed-by: Ryan Roberts > > >> --- >> Cc: Ard Biesheuvel >> Cc: Catalin Marinas >> Cc: Will Deacon >> Cc: Oliver Upton >> Cc: Anshuman Khandual >> Cc: Yue Haibing >> Cc: Mark Rutland >> Cc: Marc Zyngier >> Cc: Mark Brown >> Cc: >> --- >> arch/arm64/include/asm/mmu.h | 7 +++++++ >> arch/arm64/kernel/cpufeature.c | 5 +++-- >> arch/arm64/mm/mmu.c | 7 ------- >> 3 files changed, 10 insertions(+), 9 deletions(-) >> >> diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h >> index 6e8aa8e72601..49f1a810df16 100644 >> --- a/arch/arm64/include/asm/mmu.h >> +++ b/arch/arm64/include/asm/mmu.h >> @@ -17,6 +17,13 @@ >> #include >> #include >> >> +enum pgtable_type { >> + TABLE_PTE, >> + TABLE_PMD, >> + TABLE_PUD, >> + TABLE_P4D, >> +}; >> + >> typedef struct { >> atomic64_t id; >> #ifdef CONFIG_COMPAT >> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c >> index 9ad065f15f1d..e49d142a281f 100644 >> --- a/arch/arm64/kernel/cpufeature.c >> +++ b/arch/arm64/kernel/cpufeature.c >> @@ -84,6 +84,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -1945,11 +1946,11 @@ static bool has_pmuv3(const struct arm64_cpu_capabilities *entry, int scope) >> extern >> void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, >> phys_addr_t size, pgprot_t prot, >> - phys_addr_t (*pgtable_alloc)(int), int flags); >> + phys_addr_t (*pgtable_alloc)(enum pgtable_type), int flags); >> >> static phys_addr_t __initdata kpti_ng_temp_alloc; >> >> -static phys_addr_t __init kpti_ng_pgd_alloc(int shift) >> +static phys_addr_t __init kpti_ng_pgd_alloc(enum pgtable_type type) >> { >> kpti_ng_temp_alloc -= PAGE_SIZE; >> return kpti_ng_temp_alloc; >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index 34e5d78af076..183801520740 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -47,13 +47,6 @@ >> #define NO_CONT_MAPPINGS BIT(1) >> #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ >> >> -enum pgtable_type { >> - TABLE_PTE, >> - TABLE_PMD, >> - TABLE_PUD, >> - TABLE_P4D, >> -}; >> - >> u64 kimage_voffset __ro_after_init; >> EXPORT_SYMBOL(kimage_voffset); >> >> -- >> 2.34.1 >>