From patchwork Wed Dec 9 12:44:42 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 7808251 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 4C3FA9F387 for ; Wed, 9 Dec 2015 12:52:09 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 423732051F for ; Wed, 9 Dec 2015 12:52:08 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 27B472051D for ; Wed, 9 Dec 2015 12:52:07 +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 1a6eBs-0001Lz-7o; Wed, 09 Dec 2015 12:49:52 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1a6e8O-0006X7-Au for linux-arm-kernel@lists.infradead.org; Wed, 09 Dec 2015 12:46:21 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CD2FE5EA; Wed, 9 Dec 2015 04:45:28 -0800 (PST) Received: from leverpostej.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2E8FE3F4FF; Wed, 9 Dec 2015 04:45:49 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH 07/20] arm64: unify idmap removal Date: Wed, 9 Dec 2015 12:44:42 +0000 Message-Id: <1449665095-20774-8-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1449665095-20774-1-git-send-email-mark.rutland@arm.com> References: <1449665095-20774-1-git-send-email-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151209_044616_493259_5A7E3D00 X-CRM114-Status: GOOD ( 18.53 ) X-Spam-Score: -6.9 (------) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, lorenzo.pieralisi@arm.com, arnd@arndb.de, ard.biesheuvel@linaro.org, andre.przywara@arm.com, will.deacon@arm.com, jeremy.linton@arm.com, catalin.marinas@arm.com, labbott@fedoraproject.org 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=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_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 We currently open-code the removal of the idmap and restoration of the current task's MMU state in a few places. Before introducing yet more copies of this sequence, unify these to call a new helper, cpu_uninstall_idmap. Signed-off-by: Mark Rutland Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: Jeremy Linton Cc: Laura Abbott Cc: Lorenzo Pieralisi Cc: Will Deacon --- arch/arm64/include/asm/mmu_context.h | 25 +++++++++++++++++++++++++ arch/arm64/kernel/setup.c | 1 + arch/arm64/kernel/smp.c | 4 +--- arch/arm64/kernel/suspend.c | 20 ++++---------------- arch/arm64/mm/mmu.c | 4 +--- 5 files changed, 32 insertions(+), 22 deletions(-) diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 600eacb..b1b2514 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -27,6 +27,7 @@ #include #include #include +#include #ifdef CONFIG_PID_IN_CONTEXTIDR static inline void contextidr_thread_switch(struct task_struct *next) @@ -90,6 +91,30 @@ static inline void cpu_set_default_tcr_t0sz(void) } /* + * Remove the idmap from TTBR0_EL1 and install the pgd of the active mm. + * + * The idmap lives in the same VA range as userspace, but uses global entries + * and may use a different TCR_EL1.T0SZ. To avoid issues resulting from + * speculative TLB fetches, we must temporarily install the reserved page + * tables while we invalidate the TLBs and set up the correct TCR_EL1.T0SZ. + * + * If current is a not a user task, the mm covers the TTBR1_EL1 page tables, + * which should not be installed in TTBR0_EL1. In this case we can leave the + * reserved page tables in place. + */ +static inline void cpu_uninstall_idmap(void) +{ + struct mm_struct *mm = current->active_mm; + + cpu_set_reserved_ttbr0(); + local_flush_tlb_all(); + cpu_set_default_tcr_t0sz(); + + if (mm != &init_mm) + cpu_switch_mm(mm->pgd, mm); +} + +/* * It would be nice to return ASIDs back to the allocator, but unfortunately * that introduces a race with a generation rollover where we could erroneously * free an ASID allocated in a future generation. We could workaround this by diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 8119479..f6621ba 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -62,6 +62,7 @@ #include #include #include +#include phys_addr_t __fdt_pointer __initdata; diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index b1adc51..68e7f79 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -149,9 +149,7 @@ asmlinkage void secondary_start_kernel(void) * TTBR0 is only used for the identity mapping at this stage. Make it * point to zero page to avoid speculatively fetching new entries. */ - cpu_set_reserved_ttbr0(); - local_flush_tlb_all(); - cpu_set_default_tcr_t0sz(); + cpu_uninstall_idmap(); preempt_disable(); trace_hardirqs_off(); diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c index 1095aa4..6605539 100644 --- a/arch/arm64/kernel/suspend.c +++ b/arch/arm64/kernel/suspend.c @@ -60,7 +60,6 @@ void __init cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *)) */ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) { - struct mm_struct *mm = current->active_mm; int ret; unsigned long flags; @@ -87,22 +86,11 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) ret = __cpu_suspend_enter(arg, fn); if (ret == 0) { /* - * We are resuming from reset with TTBR0_EL1 set to the - * idmap to enable the MMU; set the TTBR0 to the reserved - * page tables to prevent speculative TLB allocations, flush - * the local tlb and set the default tcr_el1.t0sz so that - * the TTBR0 address space set-up is properly restored. - * If the current active_mm != &init_mm we entered cpu_suspend - * with mappings in TTBR0 that must be restored, so we switch - * them back to complete the address space configuration - * restoration before returning. + * We are resuming from reset with the idmap active in TTBR0_EL1. + * We must uninstall the idmap and restore the expected MMU + * state before we can possibly return to userspace. */ - cpu_set_reserved_ttbr0(); - local_flush_tlb_all(); - cpu_set_default_tcr_t0sz(); - - if (mm != &init_mm) - cpu_switch_mm(mm->pgd, mm); + cpu_uninstall_idmap(); /* * Restore per-cpu offset before any kernel diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 7559c22..98a98ac 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -450,9 +450,7 @@ void __init paging_init(void) * TTBR0 is only used for the identity mapping at this stage. Make it * point to zero page to avoid speculatively fetching new entries. */ - cpu_set_reserved_ttbr0(); - local_flush_tlb_all(); - cpu_set_default_tcr_t0sz(); + cpu_uninstall_idmap(); } /*