From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 013496B0003 for ; Sun, 3 Jun 2018 16:18:44 -0400 (EDT) Received: by mail-wr0-f197.google.com with SMTP id 33-v6so22398216wrb.12 for ; Sun, 03 Jun 2018 13:18:43 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id h6-v6si21258449wrb.44.2018.06.03.13.18.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 03 Jun 2018 13:18:42 -0700 (PDT) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w53KESIY034731 for ; Sun, 3 Jun 2018 16:18:40 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2jc8e24x8u-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 03 Jun 2018 16:18:40 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 3 Jun 2018 21:18:39 +0100 Date: Sun, 3 Jun 2018 13:18:32 -0700 From: Ram Pai Subject: Re: pkeys on POWER: Access rights not reset on execve Reply-To: Ram Pai References: <53828769-23c4-b2e3-cf59-239936819c3e@redhat.com> <20180519011947.GJ5479@ram.oc3035372033.ibm.com> <20180519202747.GK5479@ram.oc3035372033.ibm.com> <20180520060425.GL5479@ram.oc3035372033.ibm.com> <20180520191115.GM5479@ram.oc3035372033.ibm.com> MIME-Version: 1.0 In-Reply-To: Message-Id: <20180603201832.GA10109@ram.oc3035372033.ibm.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Florian Weimer Cc: Andy Lutomirski , Linux-MM , linuxppc-dev , Dave Hansen On Mon, May 21, 2018 at 01:29:11PM +0200, Florian Weimer wrote: > On 05/20/2018 09:11 PM, Ram Pai wrote: > >Florian, > > > > Does the following patch fix the problem for you? Just like x86 > > I am enabling all keys in the UAMOR register during > > initialization itself. Hence any key created by any thread at > > any time, will get activated on all threads. So any thread > > can change the permission on that key. Smoke tested it > > with your test program. > > I think this goes in the right direction, but the AMR value after > fork is still strange: > > AMR (PID 34912): 0x0000000000000000 > AMR after fork (PID 34913): 0x0000000000000000 > AMR (PID 34913): 0x0000000000000000 > Allocated key in subprocess (PID 34913): 2 > Allocated key (PID 34912): 2 > Setting AMR: 0xffffffffffffffff > New AMR value (PID 34912): 0x0fffffffffffffff > About to call execl (PID 34912) ... > AMR (PID 34912): 0x0fffffffffffffff > AMR after fork (PID 34914): 0x0000000000000003 > AMR (PID 34914): 0x0000000000000003 > Allocated key in subprocess (PID 34914): 2 > Allocated key (PID 34912): 2 > Setting AMR: 0xffffffffffffffff > New AMR value (PID 34912): 0x0fffffffffffffff > > I mean this line: > > AMR after fork (PID 34914): 0x0000000000000003 > > Shouldn't it be the same as in the parent process? Fixed it. Please try this patch. If it all works to your satisfaction, I will clean it up further and send to Michael Ellermen(ppc maintainer). commit 51f4208ed5baeab1edb9b0f8b68d7144449b3527 Author: Ram Pai Date: Sun Jun 3 14:44:32 2018 -0500 Fix for the fork bug. Signed-off-by: Ram Pai diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 1237f13..999dd08 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -582,6 +582,7 @@ static void save_all(struct task_struct *tsk) __giveup_spe(tsk); msr_check_and_clear(msr_all_available); + thread_pkey_regs_save(&tsk->thread); } void flush_all_to_thread(struct task_struct *tsk) diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index ab4519a..af6aa4a 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -294,6 +294,7 @@ void thread_pkey_regs_save(struct thread_struct *thread) */ thread->amr = read_amr(); thread->iamr = read_iamr(); + thread->uamor = read_uamor(); } void thread_pkey_regs_restore(struct thread_struct *new_thread, @@ -315,9 +316,13 @@ void thread_pkey_regs_init(struct thread_struct *thread) if (static_branch_likely(&pkey_disabled)) return; - thread->amr = read_amr() & pkey_amr_mask; - thread->iamr = read_iamr() & pkey_iamr_mask; + thread->amr = pkey_amr_mask; + thread->iamr = pkey_iamr_mask; thread->uamor = pkey_uamor_mask; + + write_uamor(pkey_uamor_mask); + write_amr(pkey_amr_mask); + write_iamr(pkey_iamr_mask); } static inline bool pkey_allows_readwrite(int pkey) > > Thanks, > Florian -- Ram Pai