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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 AC74EC46460 for ; Thu, 9 Aug 2018 06:27:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DFBE21B31 for ; Thu, 9 Aug 2018 06:27:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DFBE21B31 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=andestech.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728383AbeHIIui (ORCPT ); Thu, 9 Aug 2018 04:50:38 -0400 Received: from exmail.andestech.com ([59.124.169.137]:18923 "EHLO ATCSQR.andestech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728175AbeHIIuh (ORCPT ); Thu, 9 Aug 2018 04:50:37 -0400 Received: from mail.andestech.com (atcpcs16.andestech.com [10.0.1.222]) by ATCSQR.andestech.com with ESMTP id w796QEYN087892; Thu, 9 Aug 2018 14:26:15 +0800 (GMT-8) (envelope-from alankao@andestech.com) Received: from atcsqa06.andestech.com (10.0.1.85) by ATCPCS16.andestech.com (10.0.1.222) with Microsoft SMTP Server id 14.3.123.3; Thu, 9 Aug 2018 14:27:09 +0800 From: Alan Kao To: , , "Palmer Dabbelt" , Albert Ou , Christoph Hellwig , Andrew Waterman , Arnd Bergmann , Darius Rad CC: , , , , Alan Kao Subject: [PATCH v5 4/5] Allow to disable FPU support Date: Thu, 9 Aug 2018 14:26:42 +0800 Message-ID: <1533796003-680-5-git-send-email-alankao@andestech.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1533796003-680-1-git-send-email-alankao@andestech.com> References: <1533796003-680-1-git-send-email-alankao@andestech.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.0.1.85] X-DNSRBL: X-MAIL: ATCSQR.andestech.com w796QEYN087892 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org FPU codes have been separated from common part in previous patches. This patch add the CONFIG_FPU option and some stubs, so that a no-FPU configuration is allowed. Signed-off-by: Alan Kao Cc: Greentime Hu Cc: Vincent Chen Cc: Zong Li Cc: Nick Hu Reviewed-by: Christoph Hellwig --- arch/riscv/Kconfig | 9 +++++++++ arch/riscv/include/asm/switch_to.h | 10 ++++++++++ arch/riscv/kernel/Makefile | 2 +- arch/riscv/kernel/process.c | 4 +++- arch/riscv/kernel/signal.c | 5 +++++ 5 files changed, 28 insertions(+), 2 deletions(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 6debcc4afc72..6069597ba73f 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -232,6 +232,15 @@ config RISCV_BASE_PMU endmenu +config FPU + bool "FPU support" + default y + help + Say N here if you want to disable all floating-point related procedure + in the kernel. + + If you don't know what to do here, say Y. + endmenu menu "Kernel type" diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h index dd6b05bff75b..093050b03543 100644 --- a/arch/riscv/include/asm/switch_to.h +++ b/arch/riscv/include/asm/switch_to.h @@ -18,6 +18,7 @@ #include #include +#ifdef CONFIG_FPU extern void __fstate_save(struct task_struct *save_to); extern void __fstate_restore(struct task_struct *restore_from); @@ -55,6 +56,15 @@ static inline void __switch_to_aux(struct task_struct *prev, fstate_restore(next, task_pt_regs(next)); } +#define DEFAULT_SSTATUS (SR_SPIE | SR_FS_INITIAL) + +#else +#define fstate_save(task, regs) do { } while (0) +#define fstate_restore(task, regs) do { } while (0) +#define __switch_to_aux(__prev, __next) do { } while (0) +#define DEFAULT_SSTATUS (SR_SPIE | SR_FS_OFF) +#endif + extern struct task_struct *__switch_to(struct task_struct *, struct task_struct *); diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile index bd433efd915e..f13f7f276639 100644 --- a/arch/riscv/kernel/Makefile +++ b/arch/riscv/kernel/Makefile @@ -13,7 +13,6 @@ extra-y += vmlinux.lds obj-y += cpu.o obj-y += cpufeature.o obj-y += entry.o -obj-y += fpu.o obj-y += irq.o obj-y += process.o obj-y += ptrace.o @@ -32,6 +31,7 @@ obj-y += vdso/ CFLAGS_setup.o := -mcmodel=medany +obj-$(CONFIG_FPU) += fpu.o obj-$(CONFIG_SMP) += smpboot.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_MODULES) += module.o diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index cb209139ba53..3820d89e2db9 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -83,7 +83,7 @@ void show_regs(struct pt_regs *regs) void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) { - regs->sstatus = SR_SPIE /* User mode, irqs on */ | SR_FS_INITIAL; + regs->sstatus = DEFAULT_SSTATUS; regs->sepc = pc; regs->sp = sp; set_fs(USER_DS); @@ -91,12 +91,14 @@ void start_thread(struct pt_regs *regs, unsigned long pc, void flush_thread(void) { +#ifdef CONFIG_FPU /* * Reset FPU context * frm: round to nearest, ties to even (IEEE default) * fflags: accrued exceptions cleared */ memset(¤t->thread.fstate, 0, sizeof(current->thread.fstate)); +#endif } int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 6a18b9819ead..2450b824d799 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -37,6 +37,7 @@ struct rt_sigframe { struct ucontext uc; }; +#ifdef CONFIG_FPU static long restore_fp_state(struct pt_regs *regs, union __riscv_fp_state *sc_fpregs) { @@ -85,6 +86,10 @@ static long save_fp_state(struct pt_regs *regs, return err; } +#else +#define save_fp_state(task, regs) (0) +#define restore_fp_state(task, regs) (0) +#endif static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) -- 2.18.0