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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2409C2D0C6 for ; Fri, 27 Dec 2019 18:04:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E7E1206F4 for ; Fri, 27 Dec 2019 18:04:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="NFRzr5vX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728832AbfL0SEN (ORCPT ); Fri, 27 Dec 2019 13:04:13 -0500 Received: from smtprelay-out1.synopsys.com ([149.117.73.133]:38872 "EHLO smtprelay-out1.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727444AbfL0SEA (ORCPT ); Fri, 27 Dec 2019 13:04:00 -0500 Received: from mailhost.synopsys.com (mdc-mailhost2.synopsys.com [10.225.0.210]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by smtprelay-out1.synopsys.com (Postfix) with ESMTPS id B62A442CEB; Fri, 27 Dec 2019 18:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1577469839; bh=MNHNunTibBM6/zU1ZK+HBdMiwgE+FDn1kLfKOuU2ejU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NFRzr5vX10j5cvfrnnMxaCZizC089F49QB6wtbFU1fLS5hloQ1YiovmJEEq0VkcJh g0r1Vn1JveWXPjc0zOQ5hFpC0v0hfv3GuqanqZ3gMZaJl0fVbps3XrvqhrSb5VHTVJ f0AydX4yMezyLZkIa8AqJp1p4YFNK6gFyB2C3ldu4FBx+4or5MbEmGQozxKzgiyZBv 9KkDiaMA6ZBoi2f2NAyzXx3GRkopp2QEiPI4Xttc9AOX0fU7MeteI29UX0kP4rvohb AKO9zEaldrGqzeA2PEIjNGDySyT4bVkLZJawwn4fcvEZrGP+etXfLEYXR+K1t7awJP CWs9qfnLRZ6RA== Received: from paltsev-e7480.internal.synopsys.com (unknown [10.121.8.65]) by mailhost.synopsys.com (Postfix) with ESMTP id EB563A006C; Fri, 27 Dec 2019 18:03:56 +0000 (UTC) From: Eugeniy Paltsev To: linux-snps-arc@lists.infradead.org, Vineet Gupta Cc: linux-kernel@vger.kernel.org, Alexey Brodkin , Eugeniy Paltsev Subject: [PATCH 3/5] ARC: handle DSP presence in HW Date: Fri, 27 Dec 2019 21:03:45 +0300 Message-Id: <20191227180347.3579-4-Eugeniy.Paltsev@synopsys.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191227180347.3579-1-Eugeniy.Paltsev@synopsys.com> References: <20191227180347.3579-1-Eugeniy.Paltsev@synopsys.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In case of DSP extension presence in HW some instructions (related to integer multiply, multiply-accumulate, and divide operation) executes on this DSP execution unit. So their execution will depend on dsp configuration register (DSP_CTRL) As we want these instructions to execute the same way regardless of DSP presence we need to set DSP_CTRL properly. However this register can be modified bu any usersace app therefore any usersace may break kernel execution. Fix that by configure DSP_CTRL in CPU early code and in IRQs entries. Signed-off-by: Eugeniy Paltsev --- arch/arc/Kconfig | 25 ++++++++++++++++- arch/arc/include/asm/arcregs.h | 12 ++++++++ arch/arc/include/asm/dsp-impl.h | 45 ++++++++++++++++++++++++++++++ arch/arc/include/asm/entry-arcv2.h | 3 ++ arch/arc/kernel/head.S | 4 +++ arch/arc/kernel/setup.c | 4 +++ 6 files changed, 92 insertions(+), 1 deletion(-) create mode 100644 arch/arc/include/asm/dsp-impl.h diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 8383155c8c82..b9cd7ce3f878 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -404,13 +404,36 @@ config ARC_HAS_DIV_REM default y config ARC_HAS_ACCL_REGS - bool "Reg Pair ACCL:ACCH (FPU and/or MPY > 6)" + bool "Reg Pair ACCL:ACCH (FPU and/or MPY > 6 and/or DSP)" default y help Depending on the configuration, CPU can contain accumulator reg-pair (also referred to as r58:r59). These can also be used by gcc as GPR so kernel needs to save/restore per process +choice + prompt "DSP support" + default ARC_NO_DSP + help + Depending on the configuration, CPU can contain DSP registers + (ACC0_GLO, ACC0_GHI, DSP_BFLY0, DSP_CTRL, DSP_FFT_CTRL). + Bellow is options describing how to handle these registers in + interrupt entry / exit and in context switch. + +config ARC_NO_DSP + bool "No DSP extension presence in HW" + help + No DSP extension presence in HW + +config ARC_DSP_KERNEL + bool "DSP extension in HW, no support for userspace" + select ARC_HAS_ACCL_REGS + help + DSP extension presence in HW, no support for DSP-enabled userspace + applications. We don't save / restore DSP registers and only do + some minimal preparations so userspace won't be able to break kernel +endchoice + config ARC_IRQ_NO_AUTOSAVE bool "Disable hardware autosave regfile on interrupts" default n diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h index 5134f0baf33c..0004b1e9b325 100644 --- a/arch/arc/include/asm/arcregs.h +++ b/arch/arc/include/asm/arcregs.h @@ -116,6 +116,18 @@ #define ARC_AUX_DPFP_2H 0x304 #define ARC_AUX_DPFP_STAT 0x305 +/* + * DSP-related registers + */ +#define ARC_AUX_DSP_BUILD 0x7A +#define ARC_AUX_ACC0_LO 0x580 +#define ARC_AUX_ACC0_GLO 0x581 +#define ARC_AUX_ACC0_HI 0x582 +#define ARC_AUX_ACC0_GHI 0x583 +#define ARC_AUX_DSP_BFLY0 0x598 +#define ARC_AUX_DSP_CTRL 0x59F +#define ARC_AUX_DSP_FFT_CTRL 0x59E + #ifndef __ASSEMBLY__ #include diff --git a/arch/arc/include/asm/dsp-impl.h b/arch/arc/include/asm/dsp-impl.h new file mode 100644 index 000000000000..788093cbe689 --- /dev/null +++ b/arch/arc/include/asm/dsp-impl.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 Synopsys, Inc. (www.synopsys.com) + * + * Author: Eugeniy Paltsev + */ +#ifndef __ASM_ARC_DSP_IMPL_H +#define __ASM_ARC_DSP_IMPL_H + +#define DSP_CTRL_DISABLED_ALL 0 + +#ifdef __ASSEMBLY__ + +/* clobbers r5 register */ +.macro DSP_EARLY_INIT + lr r5, [ARC_AUX_DSP_BUILD] + bmsk r5, r5, 7 + breq r5, 0, 1f + mov r5, DSP_CTRL_DISABLED_ALL + sr r5, [ARC_AUX_DSP_CTRL] +1: +.endm + +/* clobbers r58, r59 registers pair */ +.macro DSP_SAVE_REGFILE_IRQ +#if defined(CONFIG_ARC_DSP_KERNEL) + /* Drop any changes to DSP_CTRL made by userspace so userspace won't be + * able to break kernel */ + mov r58, DSP_CTRL_DISABLED_ALL + sr r58, [ARC_AUX_DSP_CTRL] +#endif /* ARC_DSP_KERNEL */ +.endm + +#else /* __ASEMBLY__ */ + +static inline bool dsp_exist(void) +{ + struct bcr_generic bcr; + + READ_BCR(ARC_AUX_DSP_BUILD, bcr); + return !!bcr.ver; +} + +#endif /* __ASEMBLY__ */ +#endif /* __ASM_ARC_DSP_IMPL_H */ diff --git a/arch/arc/include/asm/entry-arcv2.h b/arch/arc/include/asm/entry-arcv2.h index 0b8b63d0bec1..e3f8bd3e2eba 100644 --- a/arch/arc/include/asm/entry-arcv2.h +++ b/arch/arc/include/asm/entry-arcv2.h @@ -4,6 +4,7 @@ #define __ASM_ARC_ENTRY_ARCV2_H #include +#include #include #include /* For THREAD_SIZE */ @@ -165,6 +166,8 @@ ST2 r58, r59, PT_r58 #endif + /* clobbers r58, r59 registers pair, so must be after r58, r59 save */ + DSP_SAVE_REGFILE_IRQ .endm /*------------------------------------------------------------------------*/ diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S index 6f41265f6250..6eb23f1545ee 100644 --- a/arch/arc/kernel/head.S +++ b/arch/arc/kernel/head.S @@ -14,6 +14,7 @@ #include #include #include +#include #include .macro CPU_EARLY_SETUP @@ -59,6 +60,9 @@ #endif kflag r5 #endif + ; Config DSP_CTRL properly, so kernel may use integer multiply, + ; multiply-accumulate, and divide operations + DSP_EARLY_INIT .endm .section .init.text, "ax",@progbits diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c index edb55b6ee278..b3995dd673d9 100644 --- a/arch/arc/kernel/setup.c +++ b/arch/arc/kernel/setup.c @@ -26,6 +26,7 @@ #include #include #include +#include #define FIX_PTR(x) __asm__ __volatile__(";" : "+r"(x)) @@ -444,6 +445,9 @@ static void arc_chk_core_config(void) /* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */ present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp; CHK_OPT_STRICT(CONFIG_ARC_HAS_ACCL_REGS, present); + + present = dsp_exist(); + CHK_OPT_STRICT(CONFIG_ARC_DSP_KERNEL, present); } } -- 2.21.0