From patchwork Fri Nov 11 21:50:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 624103 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAF3EC4167B for ; Fri, 11 Nov 2022 21:51:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233859AbiKKVve (ORCPT ); Fri, 11 Nov 2022 16:51:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233870AbiKKVv1 (ORCPT ); Fri, 11 Nov 2022 16:51:27 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAF236B203 for ; Fri, 11 Nov 2022 13:51:26 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5641D620FE for ; Fri, 11 Nov 2022 21:51:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2832C4347C; Fri, 11 Nov 2022 21:51:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668203485; bh=2yXo9o3hNxGIp4LEAKIBC5DAGZ6BWI4M1U6pYwioPZo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=slxKpsliT37GBNPYNdkmYX8OdBeIufnyKQcCH3NhuZqfmNw5cL91U5JdzNpGrxY8k vbwVGpPLPliwWdQ+Ga0/LYTP2it/VqIsprV3LLMLNfk8MHZ7gUfcIvwEadkF0+8GFt 8zC1Z+ywqkby4VpkHGQ7S8A+qKcc5BWQWKjZCRJ9gjU2j6LlGVirfQF0JLCkjCxlg6 jYiqrdauTi/3V8HWU7i6w+/YTlDCSIwRsP/ScMPH903viFEniXYHnfREekj0XmAdiR ypH3BCW8H/SeTqnEguo4+L8zTE9SgfVsueGocGD75A4++qCF0ViEbfgHixqrkdoO2g 4XsqQD/6hab+w== From: Mark Brown To: Catalin Marinas , Will Deacon , Shuah Khan , Shuah Khan Cc: Alan Hayward , Luis Machado , Szabolcs Nagy , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, Mark Brown Subject: [PATCH v3 12/21] arm64/sme: Implement ZT0 ptrace support Date: Fri, 11 Nov 2022 21:50:17 +0000 Message-Id: <20221111215026.813348-13-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221111215026.813348-1-broonie@kernel.org> References: <20221111215026.813348-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3346; i=broonie@kernel.org; h=from:subject; bh=2yXo9o3hNxGIp4LEAKIBC5DAGZ6BWI4M1U6pYwioPZo=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBjbsOYIHr+4F+T5foHYkSAPnY1aC9MVFsLFgrd/GU7 7tc4ET6JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCY27DmAAKCRAk1otyXVSH0GBaB/ 0W4HBP+YibvVy0anRKxj1XokeuX/SVtivA5eNM8ae9YF2IWlDpZ+qeqxmPd/wSnWp/TcYG8Pyu00oJ NOc/kFotD0xWqfn37xBycDKTbdiTK+bGJu7vB9sm8GQt3kIshKmvwIiVL2d7flitjq8lLxmvI3Zoqy cpwXDF6wWrkO7TVf+xy7hT8XFBsZS5wk/XtebWYXPuZ1QV4jRkZe7ArAaU+8WtR0vrPHSKXOHa7ZUZ AMIIBhkc9AoM90AR+RiniynjpXoQLJWkoVzkmn3/5EwzNzfmr0MGySW/i8O9zMOrbqKfXoMCLBKnlD tVSSxpkzaV/bMDe/EP/pSeDghD35SQ X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Implement support for a new note type NT_ARM64_ZT providing access to ZT0 when implemented. Since ZT0 is a register with constant size this is much simpler than for other SME state. As ZT0 is only accessible when PSTATE.ZA is set writes to ZT0 cause PSTATE.ZA to be set, the main alternative would be to return -EBUSY in this case but this seemed more constructive. Practical users are also going to be working with ZA anyway and have some understanding of the state. Signed-off-by: Mark Brown --- arch/arm64/kernel/ptrace.c | 54 ++++++++++++++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 2 files changed, 55 insertions(+) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 85105375bea5..a508f3a69d9f 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1145,6 +1145,51 @@ static int za_set(struct task_struct *target, return ret; } +static int zt_get(struct task_struct *target, + const struct user_regset *regset, + struct membuf to) +{ + if (!system_supports_sme2()) + return -EINVAL; + + /* + * If PSTATE.ZA is not set then ZT will be zeroed when it is + * enabled so report the current register value as zero. + */ + if (thread_za_enabled(&target->thread)) + membuf_write(&to, thread_zt_state(&target->thread), + ZT_SIG_REG_BYTES); + else + membuf_zero(&to, ZT_SIG_REG_BYTES); + + return 0; +} + +static int zt_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + int ret; + + if (!system_supports_sme2()) + return -EINVAL; + + if (!thread_za_enabled(&target->thread)) { + sme_alloc(target); + if (!target->thread.sme_state) + return -ENOMEM; + } + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + thread_zt_state(&target->thread), + 0, ZT_SIG_REG_BYTES); + if (ret == 0) + target->thread.svcr |= SVCR_ZA_MASK; + + return ret; +} + #endif /* CONFIG_ARM64_SME */ #ifdef CONFIG_ARM64_PTR_AUTH @@ -1367,6 +1412,7 @@ enum aarch64_regset { #ifdef CONFIG_ARM64_SVE REGSET_SSVE, REGSET_ZA, + REGSET_ZT, #endif #ifdef CONFIG_ARM64_PTR_AUTH REGSET_PAC_MASK, @@ -1474,6 +1520,14 @@ static const struct user_regset aarch64_regsets[] = { .regset_get = za_get, .set = za_set, }, + [REGSET_ZT] = { /* SME ZA */ + .core_note_type = NT_ARM_ZT, + .n = 1, + .size = ZT_SIG_REG_BYTES, + .align = sizeof(u64), + .regset_get = zt_get, + .set = zt_set, + }, #endif #ifdef CONFIG_ARM64_PTR_AUTH [REGSET_PAC_MASK] = { diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index c7b056af9ef0..3a73c853c537 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -434,6 +434,7 @@ typedef struct elf64_shdr { #define NT_ARM_PAC_ENABLED_KEYS 0x40a /* arm64 ptr auth enabled keys (prctl()) */ #define NT_ARM_SSVE 0x40b /* ARM Streaming SVE registers */ #define NT_ARM_ZA 0x40c /* ARM SME ZA registers */ +#define NT_ARM_ZT 0x40d /* ARM SME ZT registers */ #define NT_ARC_V2 0x600 /* ARCv2 accumulator/extra registers */ #define NT_VMCOREDD 0x700 /* Vmcore Device Dump Note */ #define NT_MIPS_DSP 0x800 /* MIPS DSP ASE registers */