From nobody Tue Feb 10 12:40:16 2026 Received: from mail-pg1-f181.google.com (mail-pg1-f181.google.com [209.85.215.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3D2A01494D6 for ; Wed, 14 Aug 2024 08:56:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723625789; cv=none; b=kMnT+C5NzwQqJmuEhaYiYuwtLcW8d7bMNPhGGm0njVp/a7GwS595spgKpj5KV5NYCcoH/Zv6w8QE1P5Zu5x2YQYSMEQWTf0d7ti/kyh9jdEvkpZ22yE6r9n3/vK6d3g22BKkZj+aZDR8UgvhfAS4Ye92p+/5UxUAqbmaZl38s4w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723625789; c=relaxed/simple; bh=Qv8nmYUrxUE/459kyj79Hni82zDBkNjYFIvQQBP9BGc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nEGlLZfQMX8MjAxlRrafsdydVNboOaITTIzd+C0xpd+epdUByreQmz8Pamz5q2Fwqtkro3/NDaG4pUgs6RAZtzzonEnFXBSEfY4j6AQrH1CW1F75Vx1HEOZGzicl9O26cWcoBanCoBjsL+XyRJ+Bn9mJel2mMvwhJ1wzOJj5g/w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=sifive.com; spf=pass smtp.mailfrom=sifive.com; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b=EwE01Gd4; arc=none smtp.client-ip=209.85.215.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=sifive.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sifive.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b="EwE01Gd4" Received: by mail-pg1-f181.google.com with SMTP id 41be03b00d2f7-7a115c427f1so4233555a12.0 for ; Wed, 14 Aug 2024 01:56:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; t=1723625787; x=1724230587; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=q+LcB4MC6Qgfr9kzwjEWl/9KLwOZpaXC6CA7cxVGJTI=; b=EwE01Gd42YiZ5u4ZjOn2LZve61/pxVUVDM7zYeV1p4IiEToNvV/ptVP5PM8wqqaESX sPkfxSWrtjKVfKP7YIRVDLOIaUSD/9j3b4f/zxcMhI6xuXrDMjtGy+hCHJC9eMlFfwBP bjQ212ozuONWB0eXLHBRg6BSF3xM1B8hGK28MBygp9WOJGgyPCWX8GJeBn/Vog8lo4iq 0TkD0UDyyeApQJbGjJBvBID0nNOBv5mrL1kMtSxxpL3pIVWzuvmgB8g0Ax/OHPdRgDYq yYpRLjWm0W7YwNI0ifJ7ybKu7t/ElCwZ8jnGxr+yfTOThFbrFpp5oDX3+bgTmcMomBfV DZ2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723625787; x=1724230587; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=q+LcB4MC6Qgfr9kzwjEWl/9KLwOZpaXC6CA7cxVGJTI=; b=tU/IkisdiEoYPqfY2T5jF9GKYM2aHNRBRE0t3OCTyShFT1YRLkmX/MY7b4pMzRz2JJ lb1VCZLiPa0BioGlz0Nk0pb7Dfu+PjKPknPoL13eQ0qHhhqn/f8zXOEjCFwbwMca9Cfw UxddXIfH+Jq2oCekI4MWJg2Hkimwf3B3faBJQbjQGMHAwHZCQfTfBbDB3yT7g0jLCjME eADi1Ek9zjsZFKzmFHyU28BHLD/YYKHXeCyQwLOn90SQuX3tBsSL9pnh9TfunEYZ/fIW +im02du3eep4u5d3/51t87dJIggkoBvcIoPpg1TCfzJowMlC4rH0K/SJGEe+zTvVm39T qOsg== X-Forwarded-Encrypted: i=1; AJvYcCXckfCm9Y1Dahbm7ortl3OHV1D6gyZ9XaVe8YP77dxLKo3gOtriIbviROCydqhME0nohCpoCTQIO//FrsJg4/94AMtMLJWTjODU2hlh X-Gm-Message-State: AOJu0YyW47DDSFy0gTazj02MM9lPuZ2uidzbeDHz+JldAaypGQ1UfuI2 Z21drRayzB/mbUVkwps+OTtXGklfQWJa+B4O27jtwNOPG04M6tvodHdZ9Jv31xg= X-Google-Smtp-Source: AGHT+IHeop/4tDtqPSIvDLepGfrszpRVvQ8NysDbzpZjr3VmMUvS3QBFyPVJf7l/syUiJf9jHvayiw== X-Received: by 2002:a05:6a20:c88b:b0:1c4:c879:b770 with SMTP id adf61e73a8af0-1c8eae8dd79mr2680167637.23.1723625787615; Wed, 14 Aug 2024 01:56:27 -0700 (PDT) Received: from sw06.internal.sifive.com ([4.53.31.132]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-201cd14a7b8sm25439615ad.100.2024.08.14.01.56.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Aug 2024 01:56:27 -0700 (PDT) From: Samuel Holland To: Palmer Dabbelt , linux-riscv@lists.infradead.org, Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , kasan-dev@googlegroups.com Cc: llvm@lists.linux.dev, linux-kernel@vger.kernel.org, Alexandre Ghiti , Evgenii Stepanov , Andrew Morton , linux-arm-kernel@lists.infradead.org, Samuel Holland Subject: [RFC PATCH 4/7] riscv: Do not rely on KASAN to define the memory layout Date: Wed, 14 Aug 2024 01:55:32 -0700 Message-ID: <20240814085618.968833-5-samuel.holland@sifive.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240814085618.968833-1-samuel.holland@sifive.com> References: <20240814085618.968833-1-samuel.holland@sifive.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Commit 66673099f734 ("riscv: mm: Pre-allocate vmemmap/direct map/kasan PGD entries") used the start of the KASAN shadow memory region to represent the end of the linear map, since the two memory regions were immediately adjacent. This is no longer the case for Sv39; commit 5c8405d763dc ("riscv: Extend sv39 linear mapping max size to 128G") introduced a 4 GiB hole between the regions. Introducing KASAN_SW_TAGS will cut the size of the shadow memory region in half, creating an even larger hole. Avoid wasting PGD entries on this hole by using the size of the linear map (KERN_VIRT_SIZE) to compute PAGE_END. Since KASAN_SHADOW_START/KASAN_SHADOW_END are used inside an IS_ENABLED block, it's not possible to completely hide the constants when KASAN is disabled, so provide dummy definitions for that case. Signed-off-by: Samuel Holland --- arch/riscv/include/asm/kasan.h | 11 +++++++++-- arch/riscv/mm/init.c | 2 +- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/riscv/include/asm/kasan.h b/arch/riscv/include/asm/kasan.h index e6a0071bdb56..a4e92ce9fa31 100644 --- a/arch/riscv/include/asm/kasan.h +++ b/arch/riscv/include/asm/kasan.h @@ -6,6 +6,8 @@ =20 #ifndef __ASSEMBLY__ =20 +#ifdef CONFIG_KASAN + /* * The following comment was copied from arm64: * KASAN_SHADOW_START: beginning of the kernel virtual addresses. @@ -33,13 +35,18 @@ #define KASAN_SHADOW_START ((KASAN_SHADOW_END - KASAN_SHADOW_SIZE) & PGDIR= _MASK) #define KASAN_SHADOW_END MODULES_LOWEST_VADDR =20 -#ifdef CONFIG_KASAN #define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL) =20 void kasan_init(void); asmlinkage void kasan_early_init(void); void kasan_swapper_init(void); =20 -#endif +#else /* CONFIG_KASAN */ + +#define KASAN_SHADOW_START MODULES_LOWEST_VADDR +#define KASAN_SHADOW_END MODULES_LOWEST_VADDR + +#endif /* CONFIG_KASAN */ + #endif #endif /* __ASM_KASAN_H */ diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 8b698d9609e7..1667f1b05f5a 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -1492,7 +1492,7 @@ static void __init preallocate_pgd_pages_range(unsign= ed long start, unsigned lon panic("Failed to pre-allocate %s pages for %s area\n", lvl, area); } =20 -#define PAGE_END KASAN_SHADOW_START +#define PAGE_END (PAGE_OFFSET + KERN_VIRT_SIZE) =20 void __init pgtable_cache_init(void) { --=20 2.45.1