From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79D2F1171A for ; Mon, 21 Aug 2023 20:08:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF98BC433C8; Mon, 21 Aug 2023 20:08:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1692648539; bh=+1HAN5myfBu/T1grATkD4KwhI3E6gBZVNKZdlFTtLv8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=odCRWvv8bTKOTNELtnw5qDcdCNLc2lA0OnkDkKzdxM4mjUS2DgdS0L7v16jzVmVyA Lywzen2wNum96fj628NQoW6axleJkAfhDbfa93RQJuyDg0+yyaQDx7xr78/IBG90iE 7Lquh8evOK+5ibmtLOsU19XnK+eCFEnLgjTRsEhU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mark Brown , Catalin Marinas Subject: [PATCH 6.4 211/234] arm64/ptrace: Ensure that the task sees ZT writes on first use Date: Mon, 21 Aug 2023 21:42:54 +0200 Message-ID: <20230821194138.191055135@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230821194128.754601642@linuxfoundation.org> References: <20230821194128.754601642@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Mark Brown commit 2f43f549cd0b3164ea0345e59aa3958c0d243383 upstream. When the value of ZT is set via ptrace we don't disable traps for SME. This means that when a the task has never used SME before then the value set via ptrace will never be seen by the target task since it will trigger a SME access trap which will flush the register state. Disable SME traps when setting ZT, this means we also need to allocate storage for SVE if it is not already allocated, for the benefit of streaming SVE. Fixes: f90b529bcbe5 ("arm64/sme: Implement ZT0 ptrace support") Signed-off-by: Mark Brown Cc: # 6.3.x Link: https://lore.kernel.org/r/20230816-arm64-zt-ptrace-first-use-v2-1-00aa82847e28@kernel.org Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/ptrace.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index a31af7a1abe3..187aa2b175b4 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1177,6 +1177,11 @@ static int zt_set(struct task_struct *target, if (!system_supports_sme2()) return -EINVAL; + /* Ensure SVE storage in case this is first use of SME */ + sve_alloc(target, false); + if (!target->thread.sve_state) + return -ENOMEM; + if (!thread_za_enabled(&target->thread)) { sme_alloc(target, true); if (!target->thread.sme_state) @@ -1186,8 +1191,10 @@ static int zt_set(struct task_struct *target, ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, thread_zt_state(&target->thread), 0, ZT_SIG_REG_BYTES); - if (ret == 0) + if (ret == 0) { target->thread.svcr |= SVCR_ZA_MASK; + set_tsk_thread_flag(target, TIF_SME); + } fpsimd_flush_task_state(target); -- 2.41.0