From patchwork Wed Aug 11 00:42:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vineet Gupta X-Patchwork-Id: 1515540 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; secure) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=EcaAc8n8; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=CN7kjHjE; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4Gkrf95Jz2z9sX5 for ; Wed, 11 Aug 2021 10:43:29 +1000 (AEST) 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=wwGaQ3MTsvQaWUgIr++dajCSq/wvKOrDvgsxmLkSzVM=; b=EcaAc8n8F6y+er PoOIrPU4dg9OvxhINO3tLko7slIHK4ShPrG/rngF407tX1fjwbKsVRDX9UBsuyRX8+Xy2uBXxjF5F 83VeveQbnOxKuGdhzQSPkQPETgx1E50kHA8G9WyaxgOxAgwQltYsfV6MUdJC9WzGPDQ4NUZWAQrWt 6911jsZ2gBj/zKxplDIL1N48xHzeYGZTBBjxyzsuLI4h8aLlvHJE7zxpasVgBQgIZguPbjQ4TX1C+ AAwHLXvPTHfJ7zywXHzLEZmOew8LF15a6AQBj1gNfuhEgAUhdw9vTJt7ODs82fy82ET7vUYnTdaRF bsIVu/QkUwdGWRSvKAAg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDcL9-0056mM-9L; Wed, 11 Aug 2021 00:43:27 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDcL3-0056ey-1n for linux-snps-arc@lists.infradead.org; Wed, 11 Aug 2021 00:43:23 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8227160F11; Wed, 11 Aug 2021 00:43:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628642600; bh=ALJrrGc6ovgV0DuDRmC1sw13c6c8XRN1Ta2YoCgCtk8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CN7kjHjEJKlf7pYQhCwbva8FhCN0JrpHf0lPuJGgsbNcMyWCLb6FuxHHHMH6Gsuyi 77eEhwoGxcXUZexu83WSrfDFXWGxaXY2JzLGAKFgvWYXUcM9Ynmx71I0sGiW7XVxDp H++DJ7Ee8iwEj9HYBKi7JT4VaiW0qM9ZqP4IFI8p8onJvTtSgdKuGBrQHL2ZikMypN sb0MGUPqJmr089evcC1CnuzDZHe3pcPOQOVF+s+PmHvzQOUyQUumLJ4iJrQ1g08rQo aRZ2kd1bLswsExSdBtwxu+rEvXMd0TXUmMjePX9duerkkEgXQEe/0xv/htz9hX/Utn cba0kb11dVa6w== From: Vineet Gupta To: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Anshuman Khandual , Mike Rapoport , Vineet Gupta Subject: [PATCH 10/18] ARC: mm: move MMU specific bits out of ASID allocator Date: Tue, 10 Aug 2021 17:42:50 -0700 Message-Id: <20210811004258.138075-11-vgupta@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210811004258.138075-1-vgupta@kernel.org> References: <20210811004258.138075-1-vgupta@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210810_174321_161565_F715262B X-CRM114-Status: GOOD ( 15.34 ) X-Spam-Score: -5.4 (-----) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. 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Content preview: And while at it, rewrite commentary on ASID allocator Signed-off-by: Vineet Gupta --- arch/arc/include/asm/mmu.h | 13 +++++++++++++ arch/arc/include/asm/mmu_context.h | 28 +++++++++++++ arch/arc/mm/tlb.c | 11 ++++------ [...] Content analysis details: (-5.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.2 DKIMWL_WL_HIGH DKIMwl.org - High trust sender X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org And while at it, rewrite commentary on ASID allocator Signed-off-by: Vineet Gupta --- arch/arc/include/asm/mmu.h | 13 +++++++++++++ arch/arc/include/asm/mmu_context.h | 28 +++++++++++++--------------- arch/arc/mm/tlb.c | 11 ++++------- 3 files changed, 30 insertions(+), 22 deletions(-) diff --git a/arch/arc/include/asm/mmu.h b/arch/arc/include/asm/mmu.h index 762cfe66e16b..2cabdfaf2afb 100644 --- a/arch/arc/include/asm/mmu.h +++ b/arch/arc/include/asm/mmu.h @@ -64,6 +64,19 @@ typedef struct { unsigned long asid[NR_CPUS]; /* 8 bit MMU PID + Generation cycle */ } mm_context_t; +static void inline mmu_setup_asid(struct mm_struct *mm, unsigned int asid) +{ + write_aux_reg(ARC_REG_PID, asid | MMU_ENABLE); +} + +static void inline mmu_setup_pgd(struct mm_struct *mm, pgd_t *pgd) +{ + /* PGD cached in MMU reg to avoid 3 mem lookups: task->mm->pgd */ +#ifdef CONFIG_ISA_ARCV2 + write_aux_reg(ARC_REG_SCRATCH_DATA0, (unsigned int)pgd); +#endif +} + static inline int is_pae40_enabled(void) { return IS_ENABLED(CONFIG_ARC_HAS_PAE40); diff --git a/arch/arc/include/asm/mmu_context.h b/arch/arc/include/asm/mmu_context.h index 49318a126879..dda471f5f05b 100644 --- a/arch/arc/include/asm/mmu_context.h +++ b/arch/arc/include/asm/mmu_context.h @@ -15,22 +15,23 @@ #ifndef _ASM_ARC_MMU_CONTEXT_H #define _ASM_ARC_MMU_CONTEXT_H -#include -#include #include +#include #include -/* ARC700 ASID Management +/* ARC ASID Management + * + * MMU tags TLBs with an 8-bit ASID, avoiding need to flush the TLB on + * context-switch. * - * ARC MMU provides 8-bit ASID (0..255) to TAG TLB entries, allowing entries - * with same vaddr (different tasks) to co-exit. This provides for - * "Fast Context Switch" i.e. no TLB flush on ctxt-switch + * ASID is managed per cpu, so task threads across CPUs can have different + * ASID. Global ASID management is needed if hardware supports TLB shootdown + * and/or shared TLB across cores, which ARC doesn't. * - * Linux assigns each task a unique ASID. A simple round-robin allocation - * of H/w ASID is done using software tracker @asid_cpu. - * When it reaches max 255, the allocation cycle starts afresh by flushing - * the entire TLB and wrapping ASID back to zero. + * Each task is assigned unique ASID, with a simple round-robin allocator + * tracked in @asid_cpu. When 8-bit value rolls over,a new cycle is started + * over from 0, and TLB is flushed * * A new allocation cycle, post rollover, could potentially reassign an ASID * to a different task. Thus the rule is to refresh the ASID in a new cycle. @@ -93,7 +94,7 @@ static inline void get_new_mmu_context(struct mm_struct *mm) asid_mm(mm, cpu) = asid_cpu(cpu); set_hw: - write_aux_reg(ARC_REG_PID, hw_pid(mm, cpu) | MMU_ENABLE); + mmu_setup_asid(mm, hw_pid(mm, cpu)); local_irq_restore(flags); } @@ -146,10 +147,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, */ cpumask_set_cpu(cpu, mm_cpumask(next)); -#ifdef CONFIG_ISA_ARCV2 - /* PGD cached in MMU reg to avoid 3 mem lookups: task->mm->pgd */ - write_aux_reg(ARC_REG_SCRATCH_DATA0, next->pgd); -#endif + mmu_setup_pgd(next, next->pgd); get_new_mmu_context(next); } diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c index 15cbc285b0de..b68d5798327b 100644 --- a/arch/arc/mm/tlb.c +++ b/arch/arc/mm/tlb.c @@ -716,14 +716,11 @@ void arc_mmu_init(void) if (IS_ENABLED(CONFIG_ARC_HAS_PAE40) && !mmu->pae) panic("Hardware doesn't support PAE40\n"); - /* Enable the MMU */ - write_aux_reg(ARC_REG_PID, MMU_ENABLE); + /* Enable the MMU with ASID 0 */ + mmu_setup_asid(NULL, 0); - /* In arc700/smp needed for re-entrant interrupt handling */ -#ifdef CONFIG_ISA_ARCV2 - /* swapper_pg_dir is the pgd for the kernel, used by vmalloc */ - write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir); -#endif + /* cache the pgd pointer in MMU SCRATCH reg (ARCv2 only) */ + mmu_setup_pgd(NULL, swapper_pg_dir); if (pae40_exist_but_not_enab()) write_aux_reg(ARC_REG_TLBPD1HI, 0);