From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by gnuweeb.org (Postfix) with ESMTPS id B915D7E728 for ; Wed, 30 Mar 2022 10:23:39 +0000 (UTC) Authentication-Results: gnuweeb.org; dkim=pass (1024-bit key; unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=PkFKO9wp; dkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=0yD1QCIj; dkim-atps=neutral Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 9D0121F37B; Wed, 30 Mar 2022 10:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1648635817; h=from:from:reply-to: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=SutU6NtJAmcvVDw7i47SPK0xcm6dOxLZHlPN45bee54=; b=PkFKO9wpNJaTq7DrYcMFPtlefJ9kj3nlcYwCedENhhQ/1EzYOL7r7+guxAVWoZNzqSP0rD KD5O0ataCT9mcq33DdNoEWIHx6IStvpXWcUaP468U+slwx5i+M/QH0rCqG84tl16HcIVt/ c3yR2XskLwD4eGRxfDvFt6be1wcx0lA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1648635817; h=from:from:reply-to: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=SutU6NtJAmcvVDw7i47SPK0xcm6dOxLZHlPN45bee54=; b=0yD1QCIj2M4IWRy9dWcKEl6bAzgE6V7FdqlpsjxCwMIRXss3tt3ym1PNDp2J8e5wt/MLDV 8v+uDCX2BQtxg+AA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 9049813AF3; Wed, 30 Mar 2022 10:23:37 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id tf8yI6kvRGKUdgAAMHmgww (envelope-from ); Wed, 30 Mar 2022 10:23:37 +0000 Date: Wed, 30 Mar 2022 12:23:36 +0200 From: Borislav Petkov To: kernel test robot Cc: kbuild-all@lists.01.org, GNU/Weeb Mailing List , linux-kernel@vger.kernel.org, Kees Cook Subject: Re: [ammarfaizi2-block:bp/bp/rc0+ 6/11] arch/x86/kernel/cpu/common.c:1415:10: error: 'x86_cap_flags' undeclared; did you mean 'x86_cap_flag'? Message-ID: References: <202203292206.ICsY2RKX-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <202203292206.ICsY2RKX-lkp@intel.com> List-Id: On Tue, Mar 29, 2022 at 10:23:07PM +0800, kernel test robot wrote: > tree: https://github.com/ammarfaizi2/linux-block bp/bp/rc0+ > head: 2d784fc7295963360594f3de64446aa32841c694 > commit: c3b9dcd01973935375ca9d0c67044bea7333d4ef [6/11] x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid= > config: i386-tinyconfig (https://download.01.org/0day-ci/archive/20220329/202203292206.ICsY2RKX-lkp@intel.com/config) > compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0 > reproduce (this is a W=1 build): > # https://github.com/ammarfaizi2/linux-block/commit/c3b9dcd01973935375ca9d0c67044bea7333d4ef > git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block > git fetch --no-tags ammarfaizi2-block bp/bp/rc0+ > git checkout c3b9dcd01973935375ca9d0c67044bea7333d4ef > # save the config file to linux build tree > mkdir build_dir > make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/kernel/cpu/ > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot Thanks for reporting, fixed: --- From: Borislav Petkov Date: Thu, 27 Jan 2022 12:56:21 +0100 Subject: [PATCH] x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid= Having to give the X86_FEATURE array indices in order to disable a feature bit for testing is not really user-friendly. So accept the feature bit names too. Some feature bits don't have names so there the array indices are still accepted, of course. Clearing CPUID flags is not something which should be done in production so taint the kernel too. An exemplary cmdline would then be something like: clearcpuid=de,440,smca,succory,bmi1,3dnow ("succory" is wrong on purpose). And it says: [ ... ] Clearing CPUID bits: de 13:24 smca (unknown: succory) bmi1 3dnow [ Fix CONFIG_X86_FEATURE_NAMES=n build error as reported by the 0day robot: https://lore.kernel.org/r/202203292206.ICsY2RKX-lkp@intel.com ] Signed-off-by: Borislav Petkov Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20220127115626.14179-2-bp@alien8.de --- .../admin-guide/kernel-parameters.txt | 11 +++- arch/x86/include/asm/cpufeature.h | 7 +- arch/x86/kernel/cpu/common.c | 64 +++++++++++++++---- 3 files changed, 65 insertions(+), 17 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b7ccaa2ea867..bdad3dfd6a37 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -631,12 +631,17 @@ Defaults to zero when built as a module and to 10 seconds when built into the kernel. - clearcpuid=BITNUM[,BITNUM...] [X86] + clearcpuid=X[,X...] [X86] Disable CPUID feature X for the kernel. See arch/x86/include/asm/cpufeatures.h for the valid bit - numbers. Note the Linux specific bits are not necessarily - stable over kernel options, but the vendor specific + numbers X. Note the Linux-specific bits are not necessarily + stable over kernel options, but the vendor-specific ones should be. + X can also be a string as appearing in the flags: line + in /proc/cpuinfo which does not have the above + instability issue. However, not all features have names + in /proc/cpuinfo. + Note that using this option will taint your kernel. Also note that user programs calling CPUID directly or using the feature without checking anything will still see it. This just prevents it from diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 1261842d006c..66d3e3b1d24d 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -34,14 +34,17 @@ enum cpuid_leafs CPUID_8000_001F_EAX, }; +#define X86_CAP_FMT_NUM "%d:%d" +#define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31) + #ifdef CONFIG_X86_FEATURE_NAMES extern const char * const x86_cap_flags[NCAPINTS*32]; extern const char * const x86_power_flags[32]; #define X86_CAP_FMT "%s" #define x86_cap_flag(flag) x86_cap_flags[flag] #else -#define X86_CAP_FMT "%d:%d" -#define x86_cap_flag(flag) ((flag) >> 5), ((flag) & 31) +#define X86_CAP_FMT X86_CAP_FMT_NUM +#define x86_cap_flag x86_cap_flag_num #endif /* diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index ed4417500700..69c7ea84b005 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1368,8 +1368,8 @@ static void detect_nopl(void) static void __init cpu_parse_early_param(void) { char arg[128]; - char *argptr = arg; - int arglen, res, bit; + char *argptr = arg, *opt; + int arglen, taint = 0; #ifdef CONFIG_X86_32 if (cmdline_find_option_bool(boot_command_line, "no387")) @@ -1397,21 +1397,61 @@ static void __init cpu_parse_early_param(void) return; pr_info("Clearing CPUID bits:"); - do { - res = get_option(&argptr, &bit); - if (res == 0 || res == 3) - break; - /* If the argument was too long, the last bit may be cut off */ - if (res == 1 && arglen >= sizeof(arg)) - break; + while (argptr) { + bool found __maybe_unused = false; + unsigned int bit; + + opt = strsep(&argptr, ","); + + /* + * Handle naked numbers first for feature flags which don't + * have names. + */ + if (!kstrtouint(opt, 10, &bit)) { + if (bit < NCAPINTS * 32) { + +#ifdef CONFIG_X86_FEATURE_NAMES + /* empty-string, i.e., ""-defined feature flags */ + if (!x86_cap_flags[bit]) + pr_cont(" " X86_CAP_FMT_NUM, x86_cap_flag_num(bit)); + else +#endif + pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit)); + + setup_clear_cpu_cap(bit); + taint++; + } + /* + * The assumption is that there are no feature names with only + * numbers in the name thus go to the next argument. + */ + continue; + } + +#ifdef CONFIG_X86_FEATURE_NAMES + for (bit = 0; bit < 32 * NCAPINTS; bit++) { + if (!x86_cap_flag(bit)) + continue; - if (bit >= 0 && bit < NCAPINTS * 32) { - pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit)); + if (strcmp(x86_cap_flag(bit), opt)) + continue; + + pr_cont(" %s", opt); setup_clear_cpu_cap(bit); + taint++; + found = true; + break; } - } while (res == 2); + + if (!found) + pr_cont(" (unknown: %s)", opt); +#endif + } pr_cont("\n"); + + if (taint) + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); } /* -- 2.35.1 -- Regards/Gruss, Boris. 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