From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: [RFC PATCH v2 28/28] arm64/sve: signal: Include SVE when computing AT_MINSIGSTKSZ Date: Thu, 31 Aug 2017 18:01:00 +0100 Message-ID: <1504198860-12951-29-git-send-email-Dave.Martin@arm.com> References: <1504198860-12951-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:58832 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751937AbdHaRCM (ORCPT ); Thu, 31 Aug 2017 13:02:12 -0400 In-Reply-To: <1504198860-12951-1-git-send-email-Dave.Martin@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Ard Biesheuvel , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Szabolcs Nagy , Richard Sandiford , kvmarm@lists.cs.columbia.edu, libc-alpha@sourceware.org, linux-arch@vger.kernel.org, Michael Ellerman The SVE context block in the signal frame needs to be considered too when computing the maximum possible signal frame size. Because the size of this block depends on the vector length, this patch computes the size based not on the thread's current vector length but instead on the maximum possible vector length: this determines the maximum size of SVE context block that can be observed in any signal frame for the lifetime of the process. Signed-off-by: Dave Martin Cc: Ard Biesheuvel Cc: Alex Bennée --- Changes since v1 ---------------- Changes related to Ard Biesheuvel's comments: * Fix unbalanced ifelse bracing to conform to the kernel coding style. Requested by Alex Bennée: * Thin out BUG_ON()s: Redundant BUG_ON()s and ones that just check invariants are removed. Important sanity-checks are migrated to WARN_ON()s, with some minimal best-effort patch-up code. --- arch/arm64/kernel/signal.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 7a3d6d2..c5ae575 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -594,8 +594,18 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user, if (system_supports_sve()) { unsigned int vq = 0; - if (test_thread_flag(TIF_SVE)) - vq = sve_vq_from_vl(current->thread.sve_vl); + if (add_all || test_thread_flag(TIF_SVE)) { + int vl = sve_max_vl; + + if (!add_all) + vl = current->thread.sve_vl; + + /* Fail safe if something wasn't initialised */ + if (WARN_ON(!sve_vl_valid(vl))) + vl = SVE_VL_MIN; + + vq = sve_vq_from_vl(vl); + } err = sigframe_alloc(user, &user->sve_offset, SVE_SIG_CONTEXT_SIZE(vq)); -- 2.1.4