From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=93.93.131.124 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792571903; b=ssv0JY8p7O5ZeBtoTlmnUzsLNXGUARA8G1a50PebzqpbYu2ABDP90JzrOp3bYiuf75OX uAumKoLX7iahmOoLIOx63rNQKn99HM4Qo2icjfgseHI8TYEK1r3hL3tu9PxmJERIsL/18 pRvE3iikHXJhlar46k+jl3y3MSRDn9R2cUl1aGiqDvmFRfC9p6KKFKvaSsoGc/pF/J/9G +QQchWn2P3gEz4JqIRJWDkxcXRmsQJPup2IdkjXqh5dmcacv2ylfWXJttPXNl3oGl6ZKH p9So2/feLuZxr/FRcIpF5x4Cskh2w5Hh8H8dlUu6uQJN2tz+8dBFGSFmykcOxcV3kfw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792571903; h=DMARC-Filter:DKIM-Signature:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To; bh=AOzqjtOMrdyYNSpa99+/UPGhu5nVwE5WpHEubCFaf5I=; b=OC2bIAQvLQLk01ZqnE37TmjxXEWScgUZu/O3ceBntDCcB8BIUN0mE8gORzlH1S5LE8pG hyk+8FRBo23CJhft/+hrgoTbHtyQs4tdGjf1DPJs2t9UBe2q/TZHwXRvSHpQGSnykzovf N5zTOeKdexGoSJmOCkIl8BIQHY4pGxgqwiNIt1FO2dSpLK/OGLzyAjJMIwCmkOj5znJEg /QbENL6EpTU1MY49M+gE2qqGY3QTbdcBrnxnWsqUJlcOOGNsZa+dEcczAV41myfNe7iId mE+o3gecJz2j+dZNXw3IJc8FCjrmsQRc9mAOQQGlC4XrLyx1o6wWFTqvDpCIhQmEgnQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=earth.li; spf=pass smtp.mailfrom=earth.li; dkim=pass header.d=earth.li header.i=@earth.li header.a=rsa-sha256 header.s=the header.b=U3WKM5qY; arc=none smtp.remote-ip=93.93.131.124 Received: from the.earth.li (the.earth.li [93.93.131.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91D56606A31A; Wed, 21 Oct 2026 08:38:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 91D56606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=earth.li Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=earth.li Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=earth.li header.i=@earth.li header.a=rsa-sha256 header.s=the header.b=U3WKM5qY DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=earth.li; s=the; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject: Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=AOzqjtOMrdyYNSpa99+/UPGhu5nVwE5WpHEubCFaf5I=; b=U3WKM5qYuUTXR4j3PnsdOXCn8d hUOrdeBn8f28fXuqP8owg8bfXv0XP52dwZmKyFCp7/uDoH8ijZigjM4ST7QKm2B8oGxJdV8R28Ojh weF4yGa/cnqEZhQ+tw0f05NmOz4DlcXcmYCo3TOlVHY0dkNDWesFksDJo5SHkACyjTo8wZJ3+TF76 FIEmLKlO0haAZjrmihdwsrjSU24hNEXF8/1DRXRM2UNHYMatnRoIm+pDBmtB9pLmkYd4GIFpMwuNs olG5oBlqmNEma0F+AVEP9RWpkBh/8bEDcDeKB6W+AfW5CuALH/tv3LvI/KfmXzKmJK615WqYzsReS +VVBXHRA==; Received: from noodles by the.earth.li with local (Exim 4.98.2) (envelope-from ) id 1xJRpX-00000000gFP-2wKS; Wed, 21 Oct 2026 09:37:51 +0100 Date: Wed, 21 Oct 2026 09:37:51 +0100 From: Jonathan McDowell To: Roberto Sassu Cc: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, chenhuacai@kernel.org, kernel@xen0n.name, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, robh@kernel.org, saravanak@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, zohar@linux.ibm.com, noodles@fb.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, Roberto Sassu Subject: Re: [PATCH v2] kexec: Select ima_get/free_kexec_buffer() with CONFIG_HAVE_IMA_KEXEC(_OF) Message-ID: References: <20261020083727.1906495-1-roberto.sassu@huaweicloud.com> X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261020083727.1906495-1-roberto.sassu@huaweicloud.com> On Tue, Oct 20, 2026 at 10:37:27AM +0200, Roberto Sassu wrote: > From: Roberto Sassu > > On x86, if CONFIG_OF_FLATTREE is enabled, the kernel uses the device tree > implementation of ima_get/free_kexec_buffer(). However, x86 passes the IMA > buffer location through setup_data, not through the device tree, so the > buffer is never found and the IMA measurement list is not carried over > across kexec. > > Introduce CONFIG_HAVE_IMA_KEXEC_OF (which selects CONFIG_HAVE_IMA_KEXEC) > and select it for the architectures that pass the IMA buffer location > through the device tree, via of_kexec_alloc_and_setup_fdt() (arm64, > powerpc and riscv). Build the device tree implementation of > ima_get/free_kexec_buffer() only if the new option is enabled. > > Select the new option also on LoongArch, to preserve the current behavior > and avoid a link failure. LoongArch does not pass the buffer location to > the next kernel yet; this will be addressed separately. > > Finally, don't select it for x86, and use x86's own setup_data-based > implementation regardless of CONFIG_OF_FLATTREE. > > Fixes: b69a2afd5afc ("x86/kexec: Carry forward IMA measurement log on kexec") > Signed-off-by: Roberto Sassu Reviewed-By: Jonathan McDowell I think my original intent when adding the ACPI x86 passthrough was to ensure I didn't break anything for anyone who'd been trying to use OF with x86 and pass it through, but if it wasn't even wired up there then that's not a concern. > --- > > v2: > - Reworded the commit message (no code changes), suggested by Mimi > > arch/arm64/Kconfig | 2 +- > arch/loongarch/Kconfig | 2 +- > arch/powerpc/Kconfig | 2 +- > arch/riscv/Kconfig | 2 +- > arch/x86/kernel/setup.c | 2 +- > drivers/of/kexec.c | 4 ++-- > kernel/Kconfig.kexec | 4 ++++ > 7 files changed, 11 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index b5a51b0ef944..4b7e248b6c91 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1697,7 +1697,7 @@ config ARCH_SUPPORTS_KEXEC_FILE > config ARCH_SELECTS_KEXEC_FILE > def_bool y > depends on KEXEC_FILE > - select HAVE_IMA_KEXEC if IMA > + select HAVE_IMA_KEXEC_OF if IMA > > config ARCH_SUPPORTS_KEXEC_SIG > def_bool y > diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig > index 2067d1f2ad7a..b5420d482da4 100644 > --- a/arch/loongarch/Kconfig > +++ b/arch/loongarch/Kconfig > @@ -690,7 +690,7 @@ config ARCH_SELECTS_KEXEC_FILE > depends on KEXEC_FILE > select KEXEC_ELF > select RELOCATABLE > - select HAVE_IMA_KEXEC if IMA > + select HAVE_IMA_KEXEC_OF if IMA > > config ARCH_SUPPORTS_CRASH_DUMP > def_bool 64BIT > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 2580e27e4328..096c6061893b 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -643,7 +643,7 @@ config ARCH_SELECTS_KEXEC_FILE > def_bool y > depends on KEXEC_FILE > select KEXEC_ELF > - select HAVE_IMA_KEXEC if IMA > + select HAVE_IMA_KEXEC_OF if IMA > > config PPC64_BIG_ENDIAN_ELF_ABI_V2 > # Option is available to BFD, but LLD does not support ELFv1 so this is > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index f8e26c4bed2b..161bf8a65beb 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -1118,7 +1118,7 @@ config ARCH_SUPPORTS_KEXEC_FILE > config ARCH_SELECTS_KEXEC_FILE > def_bool y > depends on KEXEC_FILE > - select HAVE_IMA_KEXEC if IMA > + select HAVE_IMA_KEXEC_OF if IMA > select KEXEC_ELF > > config ARCH_SUPPORTS_KEXEC_PURGATORY > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index cda6adb9f69c..bc17e353c099 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -421,7 +421,7 @@ static void __init add_early_ima_buffer(u64 phys_addr) > #endif > } > > -#if defined(CONFIG_HAVE_IMA_KEXEC) && !defined(CONFIG_OF_FLATTREE) > +#ifdef CONFIG_HAVE_IMA_KEXEC > int __init ima_free_kexec_buffer(void) > { > if (!ima_kexec_buffer_size) > diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c > index 029903b986cb..724f29fef0c0 100644 > --- a/drivers/of/kexec.c > +++ b/drivers/of/kexec.c > @@ -116,7 +116,7 @@ static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr, > return 0; > } > > -#ifdef CONFIG_HAVE_IMA_KEXEC > +#ifdef CONFIG_HAVE_IMA_KEXEC_OF > /** > * ima_get_kexec_buffer - get IMA buffer from the previous kernel > * @addr: On successful return, set to point to the buffer contents. > @@ -196,7 +196,7 @@ static void remove_ima_buffer(void *fdt, int chosen_node) > size_t size; > const void *prop; > > - if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC)) > + if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC_OF)) > return; > > prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len); > diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec > index 15632358bcf7..c6ed60f04ea4 100644 > --- a/kernel/Kconfig.kexec > +++ b/kernel/Kconfig.kexec > @@ -17,6 +17,10 @@ config KEXEC_ELF > config HAVE_IMA_KEXEC > bool > > +config HAVE_IMA_KEXEC_OF > + bool > + select HAVE_IMA_KEXEC > + > config KEXEC > bool "Enable kexec system call" > depends on ARCH_SUPPORTS_KEXEC > -- > 2.43.0 J. -- ... "You are in a twisty little maze of lookup tables, all different." -- Joe Zeff, The Scary Devil Monastery