kernel.git/arch/x86/include/asm/boot.h, branch linux-4.8.y

x86/KASLR: Build identity mappings on demand

2016-05-07T05:38:39Z

Currently KASLR only supports relocation in a small physical range (from 16M to 1G), due to using the initial kernel page table identity mapping. To support ranges above this, we need to have an identity mapping for the desired memory range before we can decompress (and later run) the kernel. 32-bit kernels already have the needed identity mapping. This patch adds identity mappings for the needed memory ranges on 64-bit kernels. This happens in two possible boot paths: If loaded via startup_32(), we need to set up the needed identity map. If loaded from a 64-bit bootloader, the bootloader will have already set up an identity mapping, and we'll start via the compressed kernel's startup_64(). In this case, the bootloader's page tables need to be avoided while selecting the new uncompressed kernel location. If not, the decompressor could overwrite them during decompression. To accomplish this, we could walk the pagetable and find every page that is used, and add them to mem_avoid, but this needs extra code and will require increasing the size of the mem_avoid array. Instead, we can create a new set of page tables for our own identity mapping instead. The pages for the new page table will come from the _pagetable section of the compressed kernel, which means they are already contained by in mem_avoid array. To do this, we reuse the code from the uncompressed kernel's identity mapping routines. The _pgtable will be shared by both the 32-bit and 64-bit paths to reduce init_size, as now the compressed kernel's _rodata to _end will contribute to init_size. To handle the possible mappings, we need to increase the existing page table buffer size: When booting via startup_64(), we need to cover the old VO, params, cmdline and uncompressed kernel. In an extreme case we could have them all beyond the 512G boundary, which needs (2+2)*4 pages with 2M mappings. And we'll need 2 for first 2M for VGA RAM. One more is needed for level4. This gets us to 19 pages total. When booting via startup_32(), KASLR could move the uncompressed kernel above 4G, so we need to create extra identity mappings, which should only need (2+2) pages at most when it is beyond the 512G boundary. So 19 pages is sufficient for this case as well. The resulting BOOT_*PGT_SIZE defines use the "_SIZE" suffix on their names to maintain logical consistency with the existing BOOT_HEAP_SIZE and BOOT_STACK_SIZE defines. This patch is based on earlier patches from Yinghai Lu and Baoquan He. Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Baoquan He Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Young Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jiri Kosina Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vivek Goyal Cc: Yinghai Lu Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462572095-11754-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar

x86/boot: Clean up indenting for asm/boot.h

2016-05-07T05:38:39Z

Before adding more defines to asm/boot.h, this cleans up the existing indenting for readability. Suggested-by: Ingo Molnar Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Baoquan He Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Young Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vivek Goyal Cc: Yinghai Lu Cc: kernel-hardening@lists.openwall.com Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1462572095-11754-2-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar

x86/boot: Double BOOT_HEAP_SIZE to 64KB

2016-01-11T11:30:50Z

When decompressing kernel image during x86 bootup, malloc memory for ELF program headers may run out of heap space, which leads to system halt. This patch doubles BOOT_HEAP_SIZE to 64KB. Tested with 32-bit kernel which failed to boot without this patch. Signed-off-by: H.J. Lu Acked-by: H. Peter Anvin Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Cc: Signed-off-by: Ingo Molnar

UAPI: (Scripted) Disintegrate arch/x86/include/asm

2012-12-14T22:37:13Z

Signed-off-by: David Howells Acked-by: Arnd Bergmann Acked-by: Thomas Gleixner Acked-by: Michael Kerrisk Acked-by: Paul E. McKenney Acked-by: Dave Jones

x86: Use common threadinfo allocator

2012-05-08T12:08:44Z

The only difference is the free_thread_info function, which frees xstate. Use the new arch_release_task_struct() function instead and switch over to the core allocator. Signed-off-by: Thomas Gleixner Link: http://lkml.kernel.org/r/20120505150141.559556763@linutronix.de Cc: x86@kernel.org

x86: support XZ-compressed kernel

2011-01-13T16:03:25Z

This integrates the XZ decompression code to the x86 pre-boot code. mkpiggy.c is updated to reserve about 32 KiB more buffer safety margin for kernel decompression. It is done unconditionally for all decompressors to keep the code simpler. The XZ decompressor needs around 30 KiB of heap, so the heap size is increased to 32 KiB on both x86-32 and x86-64. Documentation/x86/boot.txt is updated to list the XZ magic number. With the x86 BCJ filter in XZ, XZ-compressed x86 kernel tends to be a few percent smaller than the equivalent LZMA-compressed kernel. Signed-off-by: Lasse Collin Cc: "H. Peter Anvin" Cc: Alain Knaff Cc: Albin Tonnerre Cc: Phillip Lougher Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86: Clean up arch/x86/Kconfig*

2010-04-29T00:25:53Z

No functional change intended. Signed-off-by: Jan Beulich LKML-Reference: <4BCF2690020000780003B340@vpn.id2.novell.com> Signed-off-by: H. Peter Anvin

x86, setup: correct include file in

2009-06-25T22:16:06Z

needs , not in order to resolve PMD_SHIFT. Also, correct a +1 which really should be + THREAD_ORDER. This is a build error which was masked by a typoed #ifdef. Signed-off-by: H. Peter Anvin

x86, setup: Fix typo "CONFIG_x86_64" in

2009-06-25T20:33:11Z

CONFIG_X86_64 was misspelled (wrong case), which caused the x86-64 kernel to advertise itself as more relocatable than it really is. This could in theory cause boot failures once bootloaders start support the new relocation fields. Signed-off-by: Robert P. J. Day Signed-off-by: H. Peter Anvin

x86, boot: make kernel_alignment adjustable; new bzImage fields

2009-05-12T00:44:39Z

Make the kernel_alignment field adjustable; this allows us to set it to a large value (intended to be 16 MB to avoid ZONE_DMA contention, memory holes and other weirdness) while a smart bootloader can still force a loading at a lesser alignment if absolutely necessary. Also export pref_address (preferred loading address, corresponding to the link-time address) and init_size, the total amount of linear memory the kernel will require during initialization. [ Impact: allows better kernel placement, gives bootloader more info ] Signed-off-by: H. Peter Anvin