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[209.132.180.67]) by mx.google.com with ESMTP id sj10si3104405pab.65.2016.01.26.09.11.25; Tue, 26 Jan 2016 09:11:25 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dkim=pass header.i=@linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967013AbcAZRLT (ORCPT + 30 others); Tue, 26 Jan 2016 12:11:19 -0500 Received: from mail-wm0-f53.google.com ([74.125.82.53]:33946 "EHLO mail-wm0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966934AbcAZRLK (ORCPT ); Tue, 26 Jan 2016 12:11:10 -0500 Received: by mail-wm0-f53.google.com with SMTP id u188so115321478wmu.1 for ; Tue, 26 Jan 2016 09:11:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=3I/nmtqCLYEpjjTuCkWAeXGrt7hPGLfCJM4GrO4OO78=; b=XCF4eAw47rOYZ4QTb42VFNoH+kTs5hV5V6Etm+mGZZ9mYWbqfo5PFAspvYpu03P6sm rwelzb67Vv08+y5i1vj7VLxcunekRb9gbJy2cbXFHpBOc38jj2FIlRo+Z9KczOg5SBBe 8uNghLDYLZdjA3ibbZcbx72/QuWIfnZPmMfmo= 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=3I/nmtqCLYEpjjTuCkWAeXGrt7hPGLfCJM4GrO4OO78=; b=BuWON8Vpmx+TtCKAP/lP4fdIVFxVXoaBrOx+CQujLXZpKfRofP4scrACpo1IAdAGzC rH6gTWVQu/NHx79F5UFymzjE4aUwW30sDndgkUutwGWADcOxC+PFQebc1QFAD+FzR6Yd og4dLWa7yDOSm4c3/Ow25HdlSs0jlkY2ek2u644Kp3Uz7Ex5+4PP59Sg/Hvq/lTG6tTm 1kLYp8HIf9C7qY2FrBinM5NAEWXzuHJPYy9Qt7XtE/V+pkpNQ00FhW7p6ECb4oId02L4 VraNQ2WE/6ehQ/7VzsVcZfUPPk9MWgUhdTdTHZ8Irw7Lhm8/yr2U4KRxPKPlaRWK+5Hz FS3A== X-Gm-Message-State: AG10YOQeYjE/QnJjZw9EPykRlvUSVhOEvRWNq0tdvWQnuTCIKdhWn0F5y3Xm1EFNzF54mHtr X-Received: by 10.28.90.133 with SMTP id o127mr27211805wmb.101.1453828267650; Tue, 26 Jan 2016 09:11:07 -0800 (PST) Received: from localhost.localdomain ([195.55.142.58]) by smtp.gmail.com with ESMTPSA id ko2sm2328617wjc.9.2016.01.26.09.11.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 26 Jan 2016 09:11:06 -0800 (PST) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org, kernel-hardening@lists.openwall.com, will.deacon@arm.com, catalin.marinas@arm.com, mark.rutland@arm.com, leif.lindholm@linaro.org, keescook@chromium.org, linux-kernel@vger.kernel.org Cc: stuart.yoder@freescale.com, bhupesh.sharma@freescale.com, arnd@arndb.de, marc.zyngier@arm.com, christoffer.dall@linaro.org, labbott@fedoraproject.org, matt@codeblueprint.co.uk, Ard Biesheuvel Subject: [PATCH v4 04/22] arm64: decouple early fixmap init from linear mapping Date: Tue, 26 Jan 2016 18:10:31 +0100 Message-Id: <1453828249-14467-5-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1453828249-14467-1-git-send-email-ard.biesheuvel@linaro.org> References: <1453828249-14467-1-git-send-email-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since the early fixmap page tables are populated using pages that are part of the static footprint of the kernel, they are covered by the initial kernel mapping, and we can refer to them without using __va/__pa translations, which are tied to the linear mapping. Since the fixmap page tables are disjoint from the kernel mapping up to the top level pgd entry, we can refer to bm_pte[] directly, and there is no need to walk the page tables and perform __pa()/__va() translations at each step. Reviewed-by: Mark Rutland Signed-off-by: Ard Biesheuvel --- arch/arm64/mm/mmu.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) -- 2.5.0 diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 7711554a94f4..cb3a7bdb4e23 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -583,7 +583,7 @@ static inline pud_t * fixmap_pud(unsigned long addr) BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd)); - return pud_offset(pgd, addr); + return pud_offset_kimg(pgd, addr); } static inline pmd_t * fixmap_pmd(unsigned long addr) @@ -592,16 +592,12 @@ static inline pmd_t * fixmap_pmd(unsigned long addr) BUG_ON(pud_none(*pud) || pud_bad(*pud)); - return pmd_offset(pud, addr); + return pmd_offset_kimg(pud, addr); } static inline pte_t * fixmap_pte(unsigned long addr) { - pmd_t *pmd = fixmap_pmd(addr); - - BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd)); - - return pte_offset_kernel(pmd, addr); + return &bm_pte[pte_index(addr)]; } void __init early_fixmap_init(void) @@ -613,14 +609,14 @@ void __init early_fixmap_init(void) pgd = pgd_offset_k(addr); pgd_populate(&init_mm, pgd, bm_pud); - pud = pud_offset(pgd, addr); + pud = fixmap_pud(addr); pud_populate(&init_mm, pud, bm_pmd); - pmd = pmd_offset(pud, addr); + pmd = fixmap_pmd(addr); pmd_populate_kernel(&init_mm, pmd, bm_pte); /* * The boot-ioremap range spans multiple pmds, for which - * we are not preparted: + * we are not prepared: */ BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));