From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 91F14C433EF for ; Mon, 7 Feb 2022 15:39:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SFL8GsbIeZaYkocHDtxTYpkx13IzKonEiqMAYwSGrw4=; b=RHHadAFKsQC49l CKCyRnsNAMj4bo4Kx2bnKvO2Qjqb6jr5u8ZGvMN7WRXS4ijk9BaItA+AKT/S7VVoRg1/gOA2VrFDn wO825GWHiWfBuToUmEcyWjkCrzl4l/armH9sd6P/NT9ECrOq85y3re1pqNc7H2jbvB75kNHdzEAT5 Jy06uvNx3PWVZSO/YokKZFC76lGDaHXqtOzIMtfm5xPdclzACigBR3ypUYPefFHSxTOhOO2XZzaoB sLfCrtGdLNJWjAXMFiuQfJQ+hRmfZsW+01Bz7a+zix+6H9/WfkH0z1jI/opNdXsyphX83r/PRcw7m HV78F5gkXzhevD6VBcmw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nH65C-00AmGx-1Y; Mon, 07 Feb 2022 15:37:40 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nH5sU-00AgPO-9P for linux-arm-kernel@lists.infradead.org; Mon, 07 Feb 2022 15:24:38 +0000 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 ams.source.kernel.org (Postfix) with ESMTPS id 9FD61B815B0; Mon, 7 Feb 2022 15:24:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BB11C340EF; Mon, 7 Feb 2022 15:24:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644247467; bh=aUBAeA8epzt4DxHOr/8Fwmtcfowksew8sOb3hVCUWlo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g8i+JVslatDMxxd5F2cNYYm+E33jqOEnG1lYoDLyr4l9yc+IY3jmasGjGNhmlYlKc fAL4xSKgtV+25G09Y5D/upipQtQ9Jh7SgppVK0xdD7UJ8tGwM3fGjQuzciZcmXTZtf BUPvjNQA0PRRfHTAECZrPKRHA7Dh9xEpo5yJgkiGkDcNqjf9Nu1z7BKksDa41SSEvJ gJE3DWbkAX58SIwzhrlZAd2c5j7kDsuWgYAgRdPWIMGDSd1g3loUG8OcZqVsaiw85b LQosW1gQykbwbwVCvND0ThFA1d7lb6SKtRc+fF2l05X4aJt8Hez+oFR+/8yRWADfgt iW0LEQhYmgA5A== From: Mark Brown To: Catalin Marinas , Will Deacon , Marc Zyngier , Shuah Khan , Shuah Khan Cc: Alan Hayward , Luis Machado , Salil Akerkar , Basant Kumar Dwivedi , Szabolcs Nagy , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu, Mark Brown Subject: [PATCH v11 20/40] arm64/sme: Implement streaming SVE signal handling Date: Mon, 7 Feb 2022 15:20:49 +0000 Message-Id: <20220207152109.197566-21-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220207152109.197566-1-broonie@kernel.org> References: <20220207152109.197566-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6926; h=from:subject; bh=aUBAeA8epzt4DxHOr/8Fwmtcfowksew8sOb3hVCUWlo=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBiATjUyZffwLSh1gpayP6gvSuF62lS+Td1u15fNbZg CYIMJzOJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYgE41AAKCRAk1otyXVSH0HzsCA CCTbAUVOZGcjkDWW4cZBjJQPhdEO+fWZRGSUUHmwQxihLq5VmsZ7iX1PNJBAGSvbeoxPCbj7RdX5ai FTLLw5mFqYqtOmunhg9SgfgAaY4nKNcxwKT2y8GAFVAJ6ZGa7cpRzMDYxWY5cHN9ggyxWxTd+qNghw huwQd9YPY4W8AMhCkGV9VdAo442xbGzDYqDvfZzYzo3HCRhwvHMGArntGWydGqcHpBZvryf3KRUZAO YjInvOe4fJrmbYwZljTxO+dh/3WSx2UZcxHPwBeW+BozYrQ4kWzkeN+6T0l3UxpKXDrEA+X6OOvip/ UehWrZG0dUPBs88iSvJP1vJNDlpwcX X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220207_072430_672189_35719D2A X-CRM114-Status: GOOD ( 27.75 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When in streaming mode we have the same set of SVE registers as we do in regular SVE mode with the exception of FFR and the use of the SME vector length. Provide signal handling for these registers by taking one of the reserved words in the SVE signal context as a flags field and defining a flag with a flag which is set for streaming mode. When the flag is set the vector length is set to the streaming mode vector length and we save and restore streaming mode data. We support entering or leaving streaming mode based on the value of the flag but do not support changing the vector length, this is not currently supported SVE signal handling. We could instead allocate a separate record in the signal frame for the streaming mode SVE context but this inflates the size of the maximal signal frame required and adds complication when validating signal frames from userspace, especially given the current structure of the code. Any implementation of support for streaming mode vectors in signals will have some potential for causing issues for applications that attempt to handle SVE vectors in signals, use streaming mode but do not understand streaming mode in their signal handling code, it is hard to identify a case that is clearly better than any other - they all have cases where they could cause unexpected register corruption or faults. Signed-off-by: Mark Brown --- arch/arm64/include/uapi/asm/sigcontext.h | 16 ++++++-- arch/arm64/kernel/signal.c | 48 ++++++++++++++++++------ 2 files changed, 50 insertions(+), 14 deletions(-) diff --git a/arch/arm64/include/uapi/asm/sigcontext.h b/arch/arm64/include/uapi/asm/sigcontext.h index 0c796c795dbe..3a3366d4fbc2 100644 --- a/arch/arm64/include/uapi/asm/sigcontext.h +++ b/arch/arm64/include/uapi/asm/sigcontext.h @@ -134,9 +134,12 @@ struct extra_context { struct sve_context { struct _aarch64_ctx head; __u16 vl; - __u16 __reserved[3]; + __u16 flags; + __u16 __reserved[2]; }; +#define SVE_SIG_FLAG_SM 0x1 /* Context describes streaming mode */ + #endif /* !__ASSEMBLY__ */ #include @@ -186,9 +189,16 @@ struct sve_context { * sve_context.vl must equal the thread's current vector length when * doing a sigreturn. * + * On systems with support for SME the SVE register state may reflect either + * streaming or non-streaming mode. In streaming mode the streaming mode + * vector length will be used and the flag SVE_SIG_FLAG_SM will be set in + * the flags field. It is permitted to enter or leave streaming mode in + * a signal return, applications should take care to ensure that any difference + * in vector length between the two modes is handled, including any resixing + * and movement of context blocks. * - * Note: for all these macros, the "vq" argument denotes the SVE - * vector length in quadwords (i.e., units of 128 bits). + * Note: for all these macros, the "vq" argument denotes the vector length + * in quadwords (i.e., units of 128 bits). * * The correct way to obtain vq is to use sve_vq_from_vl(vl). The * result is valid if and only if sve_vl_valid(vl) is true. This is diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index cda04fd73333..5e6ec6ed8a1c 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -227,11 +227,17 @@ static int preserve_sve_context(struct sve_context __user *ctx) { int err = 0; u16 reserved[ARRAY_SIZE(ctx->__reserved)]; + u16 flags = 0; unsigned int vl = task_get_sve_vl(current); unsigned int vq = 0; - if (test_thread_flag(TIF_SVE)) + if (thread_sm_enabled(¤t->thread)) { + vl = task_get_sme_vl(current); vq = sve_vq_from_vl(vl); + flags |= SVE_SIG_FLAG_SM; + } else if (test_thread_flag(TIF_SVE)) { + vq = sve_vq_from_vl(vl); + } memset(reserved, 0, sizeof(reserved)); @@ -239,6 +245,7 @@ static int preserve_sve_context(struct sve_context __user *ctx) __put_user_error(round_up(SVE_SIG_CONTEXT_SIZE(vq), 16), &ctx->head.size, err); __put_user_error(vl, &ctx->vl, err); + __put_user_error(flags, &ctx->flags, err); BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved)); err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved)); @@ -259,18 +266,28 @@ static int preserve_sve_context(struct sve_context __user *ctx) static int restore_sve_fpsimd_context(struct user_ctxs *user) { int err; - unsigned int vq; + unsigned int vl, vq; struct user_fpsimd_state fpsimd; struct sve_context sve; if (__copy_from_user(&sve, user->sve, sizeof(sve))) return -EFAULT; - if (sve.vl != task_get_sve_vl(current)) + if (sve.flags & SVE_SIG_FLAG_SM) { + if (!system_supports_sme()) + return -EINVAL; + + vl = task_get_sme_vl(current); + } else { + vl = task_get_sve_vl(current); + } + + if (sve.vl != vl) return -EINVAL; if (sve.head.size <= sizeof(*user->sve)) { clear_thread_flag(TIF_SVE); + current->thread.svcr &= ~SYS_SVCR_EL0_SM_MASK; goto fpsimd_only; } @@ -302,7 +319,10 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user) if (err) return -EFAULT; - set_thread_flag(TIF_SVE); + if (sve.flags & SVE_SIG_FLAG_SM) + current->thread.svcr |= SYS_SVCR_EL0_SM_MASK; + else + set_thread_flag(TIF_SVE); fpsimd_only: /* copy the FP and status/control registers */ @@ -394,7 +414,7 @@ static int parse_user_sigframe(struct user_ctxs *user, break; case SVE_MAGIC: - if (!system_supports_sve()) + if (!system_supports_sve() && !system_supports_sme()) goto invalid; if (user->sve) @@ -593,11 +613,16 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, if (system_supports_sve()) { unsigned int vq = 0; - if (add_all || test_thread_flag(TIF_SVE)) { - int vl = sve_max_vl(); + if (add_all || test_thread_flag(TIF_SVE) || + thread_sm_enabled(¤t->thread)) { + int vl = max(sve_max_vl(), sme_max_vl()); - if (!add_all) - vl = task_get_sve_vl(current); + if (!add_all) { + if (thread_sm_enabled(¤t->thread)) + vl = task_get_sme_vl(current); + else + vl = task_get_sve_vl(current); + } vq = sve_vq_from_vl(vl); } @@ -648,8 +673,9 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user, __put_user_error(current->thread.fault_code, &esr_ctx->esr, err); } - /* Scalable Vector Extension state, if present */ - if (system_supports_sve() && err == 0 && user->sve_offset) { + /* Scalable Vector Extension state (including streaming), if present */ + if ((system_supports_sve() || system_supports_sme()) && + err == 0 && user->sve_offset) { struct sve_context __user *sve_ctx = apply_user_offset(user, user->sve_offset); err |= preserve_sve_context(sve_ctx); -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel