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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 70284C43334 for ; Fri, 10 Jun 2022 23:39:11 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4LKcqd5lpmz3f1M for ; Sat, 11 Jun 2022 09:39:09 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=H3PWXX7s; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=intel.com (client-ip=134.134.136.100; helo=mga07.intel.com; envelope-from=ira.weiny@intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=H3PWXX7s; dkim-atps=neutral Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4LKclk6rmgz3bsl for ; Sat, 11 Jun 2022 09:35:46 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1654904147; x=1686440147; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=MchtFdici9/LHAAi4sFR4mcD0phAyK+8tBE2Ictb0Iw=; b=H3PWXX7swU59nKtgN+ZEcRbD9PpABbPEgcCFAPNCPYcg+b45rL8MiMlR b51nPY0TrILvfYJjC59G0/asrtF8IQ92WCxk0oz+Zm8hygWE7hwpanppo sYsGyEXgGUUeH3v/dyGk1Lr5E1KwTtKNRQHZeVEYy304nDnU1/LxZ+isy kJeny6MvxIsmu1T3r18Pd0nI9B0+u08FKpwG7r7S4Xe2Xe01gIHPVdGMQ /cot8UPlikYgsPMwxXdjOQE9athC+sWZysqaWwH9+6m77AU4j434ICFgz 7BPmgkm/Yl3qo7SUU8Ch7JYMte5qVI4kUREwkvXygTTqLkeiwDKxPidGv g==; X-IronPort-AV: E=McAfee;i="6400,9594,10374"; a="341834940" X-IronPort-AV: E=Sophos;i="5.91,291,1647327600"; d="scan'208";a="341834940" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jun 2022 16:35:39 -0700 X-IronPort-AV: E=Sophos;i="5.91,291,1647327600"; d="scan'208";a="581302597" Received: from pleung-mobl1.amr.corp.intel.com (HELO localhost) ([10.212.33.34]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jun 2022 16:35:38 -0700 From: ira.weiny@intel.com To: linux-api@vger.kernel.org Subject: [RFC PATCH 4/6] pkeys: Lift pkey hardware check for pkey_alloc() Date: Fri, 10 Jun 2022 16:35:31 -0700 Message-Id: <20220610233533.3649584-5-ira.weiny@intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220610233533.3649584-1-ira.weiny@intel.com> References: <20220610233533.3649584-1-ira.weiny@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Florian Weimer , x86@kernel.org, clemensb@chromium.org, jkummerow@chromium.org, "Aneesh Kumar K . V" , Dave Hansen , linuxppc-dev@lists.ozlabs.org, ahaas@chromium.org, linux-kernel@vger.kernel.org, gdeepti@chromium.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Sohil Mehta , Andrew Morton , Ira Weiny , manoskouk@chromium.org, thibaudm@chromium.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Ira Weiny pkey_alloc() is documented to return ENOSPC when the hardware does not support pkeys. On x86, pkey_alloc() incorrectly returns EINVAL. This is because mm_pkey_alloc() does not check for pkey support before returning a key. Therefore, if the keys are not exhausted pkey_alloc() continues on to call arch_set_user_pkey_access(). Unfortunately, when arch_set_user_pkey_access() detects the failed support it overwrites the ENOSPC return value with EINVAL. Ensure consistent behavior across architectures by lifting this check to the core mm code. Remove a couple of 'we' references in code comments as well. Cc: ahaas@chromium.org Cc: clemensb@chromium.org Cc: gdeepti@chromium.org Cc: jkummerow@chromium.org Cc: manoskouk@chromium.org Cc: thibaudm@chromium.org Cc: Florian Weimer Cc: Sohil Mehta Cc: Andrew Morton Cc: Dave Hansen Cc: Aneesh Kumar K.V Cc: linux-api@vger.kernel.org Fixes: e8c24d3a23a4 ("x86/pkeys: Allocation/free syscalls") Signed-off-by: Ira Weiny --- Thanks to Sohil for pointing out that the commit message could be more clear WRT how EINVAL is returned incorrectly. --- arch/powerpc/include/asm/pkeys.h | 8 +++----- mm/mprotect.c | 3 +++ 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 59a2c7dbc78f..2c8351248793 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -85,18 +85,16 @@ static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) static inline int mm_pkey_alloc(struct mm_struct *mm) { /* - * Note: this is the one and only place we make sure that the pkey is + * Note: this is the one and only place to make sure that the pkey is * valid as far as the hardware is concerned. The rest of the kernel * trusts that only good, valid pkeys come out of here. */ u32 all_pkeys_mask = (u32)(~(0x0)); int ret; - if (!mmu_has_feature(MMU_FTR_PKEY)) - return -1; /* - * Are we out of pkeys? We must handle this specially because ffz() - * behavior is undefined if there are no zeros. + * Out of pkeys? Handle this specially because ffz() behavior is + * undefined if there are no zeros. */ if (mm_pkey_allocation_map(mm) == all_pkeys_mask) return -1; diff --git a/mm/mprotect.c b/mm/mprotect.c index ba5592655ee3..56d35de33725 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -773,6 +773,9 @@ SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) int pkey; int ret; + if (!arch_pkeys_enabled()) + return -ENOSPC; + /* No flags supported yet. */ if (flags) return -EINVAL; -- 2.35.1