From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38768 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966861AbdEWOsR (ORCPT ); Tue, 23 May 2017 10:48:17 -0400 Subject: Patch "powerpc/tm: Fix FP and VMX register corruption" has been added to the 4.11-stable tree To: mikey@neuling.org, gregkh@linuxfoundation.org, mpe@ellerman.id.au Cc: , From: Date: Tue, 23 May 2017 16:45:56 +0200 Message-ID: <1495550756193131@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled powerpc/tm: Fix FP and VMX register corruption to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-tm-fix-fp-and-vmx-register-corruption.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From f48e91e87e67b56bef63393d1a02c6e22c1d7078 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Mon, 8 May 2017 17:16:26 +1000 Subject: powerpc/tm: Fix FP and VMX register corruption From: Michael Neuling commit f48e91e87e67b56bef63393d1a02c6e22c1d7078 upstream. In commit dc3106690b20 ("powerpc: tm: Always use fp_state and vr_state to store live registers"), a section of code was removed that copied the current state to checkpointed state. That code should not have been removed. When an FP (Floating Point) unavailable is taken inside a transaction, we need to abort the transaction. This is because at the time of the tbegin, the FP state is bogus so the state stored in the checkpointed registers is incorrect. To fix this, we treclaim (to get the checkpointed GPRs) and then copy the thread_struct FP live state into the checkpointed state. We then trecheckpoint so that the FP state is correctly restored into the CPU. The copying of the FP registers from live to checkpointed is what was missing. This simplifies the logic slightly from the original patch. tm_reclaim_thread() will now always write the checkpointed FP state. Either the checkpointed FP state will be written as part of the actual treclaim (in tm.S), or it'll be a copy of the live state. Which one we use is based on MSR[FP] from userspace. Similarly for VMX. Fixes: dc3106690b20 ("powerpc: tm: Always use fp_state and vr_state to store live registers") Signed-off-by: Michael Neuling Reviewed-by: cyrilbur@gmail.com Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/process.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -864,6 +864,25 @@ static void tm_reclaim_thread(struct thr if (!MSR_TM_SUSPENDED(mfmsr())) return; + /* + * If we are in a transaction and FP is off then we can't have + * used FP inside that transaction. Hence the checkpointed + * state is the same as the live state. We need to copy the + * live state to the checkpointed state so that when the + * transaction is restored, the checkpointed state is correct + * and the aborted transaction sees the correct state. We use + * ckpt_regs.msr here as that's what tm_reclaim will use to + * determine if it's going to write the checkpointed state or + * not. So either this will write the checkpointed registers, + * or reclaim will. Similarly for VMX. + */ + if ((thr->ckpt_regs.msr & MSR_FP) == 0) + memcpy(&thr->ckfp_state, &thr->fp_state, + sizeof(struct thread_fp_state)); + if ((thr->ckpt_regs.msr & MSR_VEC) == 0) + memcpy(&thr->ckvr_state, &thr->vr_state, + sizeof(struct thread_vr_state)); + giveup_all(container_of(thr, struct task_struct, thread)); tm_reclaim(thr, thr->ckpt_regs.msr, cause); Patches currently in stable-queue which might be from mikey@neuling.org are queue-4.11/powerpc-tm-fix-fp-and-vmx-register-corruption.patch