From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 28 May 2018 13:05:34 +0200 (CEST) Received: from mail.kernel.org ([198.145.29.99]:44736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23994850AbeE1LEdAZuQ0 (ORCPT ); Mon, 28 May 2018 13:04:33 +0200 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5EAAF2087E; Mon, 28 May 2018 11:04:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1527505466; bh=zPJ5We2s1tTVTnUx6DuGrawXm/zWI8FOqgcj00xqjzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xHhY0ZJB1gpFqOSvnRy7Rh5XLPqv8Mdo+g9FlWEwEYuyAn8otHKpL5SrO4Ob5Dz5u H1/+qtyJiKHNlqeekVyaNFzd1rMnQhpZEHw3AEGTpXYwXqlWaVb7FGP9hA8FgxEg4H TmKTFzfF9/6wmYQHYNkIBnbxvnv8D/1iaLltoeYc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Hogan , "Maciej W. Rozycki" , Ralf Baechle , linux-mips@linux-mips.org Subject: [PATCH 4.16 005/272] MIPS: ptrace: Expose FIR register through FP regset Date: Mon, 28 May 2018 12:00:38 +0200 Message-Id: <20180528100240.636170749@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100240.256525891@linuxfoundation.org> References: <20180528100240.256525891@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 64113 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: gregkh@linuxfoundation.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maciej W. Rozycki commit 71e909c0cdad28a1df1fa14442929e68615dee45 upstream. Correct commit 7aeb753b5353 ("MIPS: Implement task_user_regset_view.") and expose the FIR register using the unused 4 bytes at the end of the NT_PRFPREG regset. Without that register included clients cannot use the PTRACE_GETREGSET request to retrieve the complete FPU register set and have to resort to one of the older interfaces, either PTRACE_PEEKUSR or PTRACE_GETFPREGS, to retrieve the missing piece of data. Also the register is irreversibly missing from core dumps. This register is architecturally hardwired and read-only so the write path does not matter. Ignore data supplied on writes then. Fixes: 7aeb753b5353 ("MIPS: Implement task_user_regset_view.") Signed-off-by: James Hogan Signed-off-by: Maciej W. Rozycki Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: # 3.13+ Patchwork: https://patchwork.linux-mips.org/patch/19273/ Signed-off-by: James Hogan Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/ptrace.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -463,7 +463,7 @@ static int fpr_get_msa(struct task_struc /* * Copy the floating-point context to the supplied NT_PRFPREG buffer. * Choose the appropriate helper for general registers, and then copy - * the FCSR register separately. + * the FCSR and FIR registers separately. */ static int fpr_get(struct task_struct *target, const struct user_regset *regset, @@ -471,6 +471,7 @@ static int fpr_get(struct task_struct *t void *kbuf, void __user *ubuf) { const int fcr31_pos = NUM_FPU_REGS * sizeof(elf_fpreg_t); + const int fir_pos = fcr31_pos + sizeof(u32); int err; if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) @@ -483,6 +484,12 @@ static int fpr_get(struct task_struct *t err = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &target->thread.fpu.fcr31, fcr31_pos, fcr31_pos + sizeof(u32)); + if (err) + return err; + + err = user_regset_copyout(&pos, &count, &kbuf, &ubuf, + &boot_cpu_data.fpu_id, + fir_pos, fir_pos + sizeof(u32)); return err; } @@ -531,7 +538,8 @@ static int fpr_set_msa(struct task_struc /* * Copy the supplied NT_PRFPREG buffer to the floating-point context. * Choose the appropriate helper for general registers, and then copy - * the FCSR register separately. + * the FCSR register separately. Ignore the incoming FIR register + * contents though, as the register is read-only. * * We optimize for the case where `count % sizeof(elf_fpreg_t) == 0', * which is supposed to have been guaranteed by the kernel before @@ -545,6 +553,7 @@ static int fpr_set(struct task_struct *t const void *kbuf, const void __user *ubuf) { const int fcr31_pos = NUM_FPU_REGS * sizeof(elf_fpreg_t); + const int fir_pos = fcr31_pos + sizeof(u32); u32 fcr31; int err; @@ -572,6 +581,11 @@ static int fpr_set(struct task_struct *t ptrace_setfcr31(target, fcr31); } + if (count > 0) + err = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, + fir_pos, + fir_pos + sizeof(u32)); + return err; }