From patchwork Thu May 1 15:49:34 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 4099421 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C8648C0ACC for ; Thu, 1 May 2014 15:52:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DBBEF20328 for ; Thu, 1 May 2014 15:52:54 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D26A52034C for ; Thu, 1 May 2014 15:52:53 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WftFq-0007YN-7G; Thu, 01 May 2014 15:50:34 +0000 Received: from mail-we0-f177.google.com ([74.125.82.177]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WftFY-0006AW-0Z for linux-arm-kernel@lists.infradead.org; Thu, 01 May 2014 15:50:16 +0000 Received: by mail-we0-f177.google.com with SMTP id t60so3287717wes.22 for ; Thu, 01 May 2014 08:49:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=0u1bgPG/6eKtOX3AOn7av2yySF5gZgEqo5ch2XRKBF4=; b=acTZ84E0ClbptDY8X7QBow6XrstfB+1HS7F6PSEf+AJJnJzMnIm+/d28X2pVUL9yyB KMHkvcYkgfcSAWXi30ptFSgqxq3jO33nuZnE7tzD5sOjlb7T3CMYwg06SpdorYoiONy1 xTIROwe9EnSJ+D8zP7P/MFESL9dPCWPekvXXT6m0fj+eUpU5enNvxHLzg2TgS52TG1cB bxD2VNQsLN4u2jcf8UwtmyAiu3OKGUxN88ePDkpa5q1rJu4nGTYtEGKSjP5Ut+KcX5oe bOtLnW51jI+WGRl75+p6r7zEBGuQlneqbLP69Lk3YTMsQrdQAbYNgs4ETdGizmzT+GWS YNsw== X-Gm-Message-State: ALoCoQm41bcPBWL+ne/7QE5RpkNR1uT11/pUGE3tZNi/gJ98JEP53rEF96syivSSnzEdvgFfle1x X-Received: by 10.180.210.238 with SMTP id mx14mr2625837wic.61.1398959390966; Thu, 01 May 2014 08:49:50 -0700 (PDT) Received: from ards-macbook-pro.local (cag06-7-83-153-85-71.fbx.proxad.net. [83.153.85.71]) by mx.google.com with ESMTPSA id jd2sm4457326wic.9.2014.05.01.08.49.49 for (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 01 May 2014 08:49:50 -0700 (PDT) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org Subject: [PATCH resend 02/15] arm64: add abstractions for FPSIMD state manipulation Date: Thu, 1 May 2014 17:49:34 +0200 Message-Id: <1398959381-8126-3-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1398959381-8126-1-git-send-email-ard.biesheuvel@linaro.org> References: <1398959381-8126-1-git-send-email-ard.biesheuvel@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140501_085016_260536_153321A0 X-CRM114-Status: GOOD ( 15.58 ) X-Spam-Score: -0.7 (/) Cc: catalin.marinas@arm.com, will.deacon@arm.com, steve.capper@linaro.org, Ard Biesheuvel X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There are two tacit assumptions in the FPSIMD handling code that will no longer hold after the next patch that optimizes away some FPSIMD state restores: . the FPSIMD registers of this CPU contain the userland FPSIMD state of task 'current'; . when switching to a task, its FPSIMD state will always be restored from memory. This patch adds the following functions to abstract away from straight FPSIMD register file saves and restores: - fpsimd_preserve_current_state -> ensure current's FPSIMD state is saved - fpsimd_restore_current_state -> ensure current's FPSIMD state is loaded - fpsimd_update_current_state -> replace current's FPSIMD state - fpsimd_flush_task_state -> invalidate live copies of a task's FPSIMD state Where necessary, the ptrace, signal handling and fork code are updated to use the above wrappers instead of poking into the FPSIMD registers directly. Signed-off-by: Ard Biesheuvel --- arch/arm64/include/asm/fpsimd.h | 6 ++++++ arch/arm64/kernel/fpsimd.c | 33 +++++++++++++++++++++++++++++++++ arch/arm64/kernel/process.c | 2 +- arch/arm64/kernel/ptrace.c | 2 ++ arch/arm64/kernel/signal.c | 9 +++------ arch/arm64/kernel/signal32.c | 9 +++------ 6 files changed, 48 insertions(+), 13 deletions(-) diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index c43b4ac13008..9f9b8e438546 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -58,6 +58,12 @@ extern void fpsimd_load_state(struct fpsimd_state *state); extern void fpsimd_thread_switch(struct task_struct *next); extern void fpsimd_flush_thread(void); +extern void fpsimd_preserve_current_state(void); +extern void fpsimd_restore_current_state(void); +extern void fpsimd_update_current_state(struct fpsimd_state *state); + +extern void fpsimd_flush_task_state(struct task_struct *target); + #endif #endif diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 4aef42a04bdc..86ac6a9bc86a 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -87,6 +87,39 @@ void fpsimd_flush_thread(void) preempt_enable(); } +/* + * Save the userland FPSIMD state of 'current' to memory + */ +void fpsimd_preserve_current_state(void) +{ + fpsimd_save_state(¤t->thread.fpsimd_state); +} + +/* + * Load the userland FPSIMD state of 'current' from memory + */ +void fpsimd_restore_current_state(void) +{ + fpsimd_load_state(¤t->thread.fpsimd_state); +} + +/* + * Load an updated userland FPSIMD state for 'current' from memory + */ +void fpsimd_update_current_state(struct fpsimd_state *state) +{ + preempt_disable(); + fpsimd_load_state(state); + preempt_enable(); +} + +/* + * Invalidate live CPU copies of task t's FPSIMD state + */ +void fpsimd_flush_task_state(struct task_struct *t) +{ +} + #ifdef CONFIG_KERNEL_MODE_NEON /* diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 6391485f342d..c5693163408c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -205,7 +205,7 @@ void release_thread(struct task_struct *dead_task) int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { - fpsimd_save_state(¤t->thread.fpsimd_state); + fpsimd_preserve_current_state(); *dst = *src; return 0; } diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 6a8928bba03c..f8700eca24e7 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -517,6 +517,7 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset, return ret; target->thread.fpsimd_state.user_fpsimd = newstate; + fpsimd_flush_task_state(target); return ret; } @@ -764,6 +765,7 @@ static int compat_vfp_set(struct task_struct *target, uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK; } + fpsimd_flush_task_state(target); return ret; } diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 890a591f75dd..06448a77ff53 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -51,7 +51,7 @@ static int preserve_fpsimd_context(struct fpsimd_context __user *ctx) int err; /* dump the hardware registers to the fpsimd_state structure */ - fpsimd_save_state(fpsimd); + fpsimd_preserve_current_state(); /* copy the FP and status/control registers */ err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs)); @@ -86,11 +86,8 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx) __get_user_error(fpsimd.fpcr, &ctx->fpcr, err); /* load the hardware registers from the fpsimd_state structure */ - if (!err) { - preempt_disable(); - fpsimd_load_state(&fpsimd); - preempt_enable(); - } + if (!err) + fpsimd_update_current_state(&fpsimd); return err ? -EFAULT : 0; } diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index b3fc9f5ec6d3..ac7e237d0bda 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -219,7 +219,7 @@ static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) * Note that this also saves V16-31, which aren't visible * in AArch32. */ - fpsimd_save_state(fpsimd); + fpsimd_preserve_current_state(); /* Place structure header on the stack */ __put_user_error(magic, &frame->magic, err); @@ -282,11 +282,8 @@ static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) * We don't need to touch the exception register, so * reload the hardware state. */ - if (!err) { - preempt_disable(); - fpsimd_load_state(&fpsimd); - preempt_enable(); - } + if (!err) + fpsimd_update_current_state(&fpsimd); return err ? -EFAULT : 0; }