From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1F3FD1E9B14 for ; Mon, 21 Apr 2025 18:52:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745261570; cv=none; b=B/BGdqYuhTX8TobOnZdWy6gLezCbv8DgQNX8I+2TY8jh/z7EXiRH5aV+Xs2KXEdxIgd8QNIjXPNrMTiTQvCMHedewgpPQx9Z1UZmoIkD5Ab2HRgRS4yOTxmjgydHd2Y/+rI+oxJmO59kX14/qAfIgpu2Zx4jRfK5VA+BWXF1TQQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745261570; c=relaxed/simple; bh=n/05AM9cDZsJyylm38jCM67fcEj3iUy1XLO41j3i3/Y=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ES0764CPjHEVY+qknuwLpNY7luXlr8vvBRiuWzrme+lhjd5h/krR/S5Zl8DLqIy8QcETZeeY8jijaerEgyoLUhK5D02CSnLRfhMJ91wsK4UXLCPsOuiQGkfR07ywUl+cWI5dVeMwOK6MWkWiqNTojLtDSRL3ZUcfvAAvPnKsi0w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=srEblvVm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="srEblvVm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20E23C4CEE4; Mon, 21 Apr 2025 18:52:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745261569; bh=n/05AM9cDZsJyylm38jCM67fcEj3iUy1XLO41j3i3/Y=; h=From:To:Cc:Subject:Date:From; b=srEblvVmRAmmADNIcPqDoz5NiuJXl2NjfwBfZbdfSxs8mkS2ar/Jrn+CuWMqgaJ1G 1+UFOJzdH/NGeK8aLKqUifO6dPXomyDxOKE1vG6AzN2v7BO40lNJu1oOm9lXHj99Pz 2v/8LHBZYhjBQ4dhIZGA15wqp+2veA4ZVQkj4W7IYZHSa2s9JhcM/HJX4XlqDRFIH3 W6NOcnFcGpT4/uTvLnqEkvhXdUnRTgw46kZ9y6XuYa1wjK27bIFi/Ps15d/iQlcUVE z3kBO93g7U0ndMFhQSyt5gM9rsISblKwGSOetEMMsvJLM3GZMNTrg+NDkoJvSlfAbI hclLEKUWVxbzQ== From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: Andy Shevchenko , Arnd Bergmann , Borislav Petkov , Juergen Gross , "H . Peter Anvin" , Kees Cook , Linus Torvalds , Mike Rapoport , Paul Menzel , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 00/29] x86/boot/e820: Assorted E820 table handling features and cleanups Date: Mon, 21 Apr 2025 20:51:40 +0200 Message-ID: <20250421185210.3372306-1-mingo@kernel.org> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit So I was looking into a E820 table related bug report by Paul Menzel, and I wanted to implement the behavior suggested by the ACPI specification, which bug/problem results in unbootable Linux systems with certain bootloaders: https://lore.kernel.org/r/074c2637-1b65-428e-b3e2-24384780e936@molgen.mpg.de One thing led to another, and now I'm here 29 patches later, trying to explain what they all do. :-/ In order of importance: - The bugfix / change of Linux kernel E820 table parsing behavior: x86/boot/e820: Treat non-type-2 'reserved' E820 region types as E820_TYPE_RESERVED - A change to e820_search_gap() to fix an implementational oddity that would prefer lower-address same-size PCI gaps over larger-address PCI gaps. Now the implementation searches for the largest gap: x86/boot/e820: Change e820_search_gap() to search for the highest-address PCI gap - A rewrite of e820_search_gap() to search the E820 table in ascending order to make sure even weird PCI holes get found, as claimed by the comments around the code (but not properly implemented): x86/boot/e820: Make sure e820_search_gap() finds all gaps - Remove the exclusion of single-entry E820 tables passed in by firmware: x86/boot/e820: Simplify append_e820_table() and remove restriction on single-entry tables - A debuggability improvement, to print the sizes of the e820 entries and the holes as well, because parsing raw hexadecimal ranges is hard for humans: x86/boot/e820: Print gaps in the E820 table x86/boot/e820: Print out sizes of E820 memory ranges Before: BIOS-provided physical RAM map: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved BIOS-e820: [mem 0x0000000000100000-0x000000007ffdbfff] usable BIOS-e820: [mem 0x000000007ffdc000-0x000000007fffffff] reserved BIOS-e820: [mem 0x00000000b0000000-0x00000000bfffffff] reserved BIOS-e820: [mem 0x00000000fed1c000-0x00000000fed1ffff] reserved BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved BIOS-e820: [mem 0x000000fd00000000-0x000000ffffffffff] reserved After: BIOS-provided physical RAM map: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] 639 KB kernel usable RAM BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] 1 KB device reserved BIOS-e820: [gap 0x00000000000a0000-0x00000000000effff] 320 KB ... BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] 64 KB device reserved BIOS-e820: [mem 0x0000000000100000-0x000000007ffdbfff] 1.9 GB kernel usable RAM BIOS-e820: [mem 0x000000007ffdc000-0x000000007fffffff] 144 KB device reserved BIOS-e820: [gap 0x0000000080000000-0x00000000afffffff] 768 MB ... BIOS-e820: [mem 0x00000000b0000000-0x00000000bfffffff] 256 MB device reserved BIOS-e820: [gap 0x00000000c0000000-0x00000000fed1bfff] 1005.1 MB ... BIOS-e820: [mem 0x00000000fed1c000-0x00000000fed1ffff] 16 KB device reserved BIOS-e820: [gap 0x00000000fed20000-0x00000000feffbfff] 2.8 MB ... BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] 16 KB device reserved BIOS-e820: [gap 0x00000000ff000000-0x00000000fffbffff] 15.7 MB ... BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] 256 KB device reserved BIOS-e820: [gap 0x0000000100000000-0x000000fcffffffff] 1008 GB ... BIOS-e820: [mem 0x000000fd00000000-0x000000ffffffffff] 12 GB device reserved Note how weirdly broken up ranges are printed with fractional size values, while 'round' ranges are printed as natural numbers. - Assorted cleanups: type cleanups, simplifications, standardization of coding patterns, etc. The tree can be found in the WIP.x86/e820 branch of the mingo/tip.git tree: git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git WIP.x86/e820 It's lightly tested at the moment. Thanks, Ingo ===============> Ingo Molnar (29): x86/boot/e820: Remove inverted boolean logic from the e820_nomerge() function name, rename it to e820_type_mergeable() x86/boot/e820: Simplify e820__print_table() a bit x86/boot/e820: Simplify the PPro Erratum #50 workaround x86/boot/e820: Mark e820__print_table() static x86/boot/e820: Print gaps in the E820 table x86/boot/e820: Make the field separator space character part of e820_print_type() x86/boot/e820: Print out sizes of E820 memory ranges x86/boot/e820: Print E820_TYPE_RAM entries as ... RAM entries x86/boot/e820: Call the PCI gap a 'gap' in the boot log printout x86/boot/e820: Use 'u64' consistently instead of 'unsigned long long' x86/boot/e820: Remove pointless early_panic() indirection x86/boot/e820: Clean up confusing and self-contradictory verbiage around E820 related resource allocations x86/boot/e820: Improve e820_print_type() messages x86/boot/e820: Clean up __e820__range_add() a bit x86/boot/e820: Clean up __refdata use a bit x86/boot/e820: Remove unnecessary header inclusions x86/boot/e820: Standardize e820 table index variable names under 'idx' x86/boot/e820: Change struct e820_table::nr_entries type from __u32 to u32 x86/boot/e820: Standardize e820 table index variable types under 'u32' x86/boot/e820: Clean up e820__setup_pci_gap()/e820_search_gap() a bit x86/boot/e820: Change e820_search_gap() to search for the highest-address PCI gap x86/boot/e820: Rename gap_start/gap_size to max_gap_start/max_gap_start in e820_search_gap() et al x86/boot/e820: Simplify & clarify __e820__range_add() a bit x86/boot/e820: Standardize __init/__initdata tag placement x86/boot/e820: Simplify append_e820_table() and remove restriction on single-entry tables x86/boot/e820: Remove e820__range_remove()'s unused return parameter x86/boot/e820: Simplify the e820__range_remove() API x86/boot/e820: Make sure e820_search_gap() finds all gaps x86/boot/e820: Treat non-type-2 'reserved' E820 region types as E820_TYPE_RESERVED arch/x86/include/asm/e820/api.h | 3 +- arch/x86/include/asm/e820/types.h | 2 +- arch/x86/kernel/e820.c | 518 ++++++++++++++++++++++---------------- arch/x86/kernel/setup.c | 10 +- arch/x86/platform/efi/efi.c | 3 +- 5 files changed, 307 insertions(+), 229 deletions(-) -- 2.45.2