From patchwork Sun Feb 21 01:23:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Christopher M. Riedl" X-Patchwork-Id: 1442744 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4Djnhm3826z9sBJ for ; Sun, 21 Feb 2021 12:26:32 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Djnhm25wxz3dQp for ; Sun, 21 Feb 2021 12:26:32 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=codefail.de (client-ip=68.65.122.27; helo=mta-07-4.privateemail.com; envelope-from=cmr@codefail.de; receiver=) Received: from MTA-07-4.privateemail.com (mta-07-4.privateemail.com [68.65.122.27]) (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 4Djnf407mVz30Lg for ; Sun, 21 Feb 2021 12:24:10 +1100 (AEDT) Received: from MTA-07.privateemail.com (localhost [127.0.0.1]) by MTA-07.privateemail.com (Postfix) with ESMTP id 934B760051; Sat, 20 Feb 2021 20:24:08 -0500 (EST) Received: from oc8246131445.ibm.com (unknown [10.20.151.213]) by MTA-07.privateemail.com (Postfix) with ESMTPA id 5AB1260049; Sun, 21 Feb 2021 01:24:08 +0000 (UTC) From: "Christopher M. Riedl" To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH v6 08/10] powerpc/signal64: Rewrite handle_rt_signal64() to minimise uaccess switches Date: Sat, 20 Feb 2021 19:23:59 -0600 Message-Id: <20210221012401.22328-9-cmr@codefail.de> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20210221012401.22328-1-cmr@codefail.de> References: <20210221012401.22328-1-cmr@codefail.de> MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP 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: Daniel Axtens Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Daniel Axtens Add uaccess blocks and use the 'unsafe' versions of functions doing user access where possible to reduce the number of times uaccess has to be opened/closed. There is no 'unsafe' version of copy_siginfo_to_user, so move it slightly to allow for a "longer" uaccess block. Signed-off-by: Daniel Axtens Co-developed-by: Christopher M. Riedl Signed-off-by: Christopher M. Riedl --- arch/powerpc/kernel/signal_64.c | 56 ++++++++++++++++++++------------- 1 file changed, 35 insertions(+), 21 deletions(-) diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index 76b525261f61..4bf73731533f 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -853,45 +853,52 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, unsigned long msr = regs->msr; frame = get_sigframe(ksig, tsk, sizeof(*frame), 0); - if (!access_ok(frame, sizeof(*frame))) - goto badframe; - err |= __put_user(&frame->info, &frame->pinfo); - err |= __put_user(&frame->uc, &frame->puc); - err |= copy_siginfo_to_user(&frame->info, &ksig->info); - if (err) + /* This only applies when calling unsafe_setup_sigcontext() and must be + * called before opening the uaccess window. + */ + if (!MSR_TM_ACTIVE(msr)) + prepare_setup_sigcontext(tsk); + + if (!user_write_access_begin(frame, sizeof(*frame))) goto badframe; + unsafe_put_user(&frame->info, &frame->pinfo, badframe_block); + unsafe_put_user(&frame->uc, &frame->puc, badframe_block); + /* Create the ucontext. */ - err |= __put_user(0, &frame->uc.uc_flags); - err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]); + unsafe_put_user(0, &frame->uc.uc_flags, badframe_block); + unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block); if (MSR_TM_ACTIVE(msr)) { #ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* The ucontext_t passed to userland points to the second * ucontext_t (for transactional state) with its uc_link ptr. */ - err |= __put_user(&frame->uc_transact, &frame->uc.uc_link); + unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block); + + user_write_access_end(); + err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext, &frame->uc_transact.uc_mcontext, tsk, ksig->sig, NULL, (unsigned long)ksig->ka.sa.sa_handler, msr); + + if (!user_write_access_begin(&frame->uc.uc_sigmask, + sizeof(frame->uc.uc_sigmask))) + goto badframe; + #endif } else { - err |= __put_user(0, &frame->uc.uc_link); - prepare_setup_sigcontext(tsk); - if (!user_write_access_begin(&frame->uc.uc_mcontext, - sizeof(frame->uc.uc_mcontext))) - return -EFAULT; - err |= __unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, - ksig->sig, NULL, - (unsigned long)ksig->ka.sa.sa_handler, 1); - user_write_access_end(); + unsafe_put_user(0, &frame->uc.uc_link, badframe_block); + unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig, + NULL, (unsigned long)ksig->ka.sa.sa_handler, + 1, badframe_block); } - err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); - if (err) - goto badframe; + + unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block); + user_write_access_end(); /* Make sure signal handler doesn't get spurious FP exceptions */ tsk->thread.fp_state.fpscr = 0; @@ -906,6 +913,11 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, regs->nip = (unsigned long) &frame->tramp[0]; } + + /* Save the siginfo outside of the unsafe block. */ + if (copy_siginfo_to_user(&frame->info, &ksig->info)) + goto badframe; + /* Allocate a dummy caller frame for the signal handler. */ newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); @@ -945,6 +957,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, return 0; +badframe_block: + user_write_access_end(); badframe: signal_fault(current, regs, "handle_rt_signal64", frame);