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2016-04-29x86/boot: Move compressed kernel to the end of the decompression bufferYinghai Lu1-0/+17
This change makes later calculations about where the kernel is located easier to reason about. To better understand this change, we must first clarify what 'VO' and 'ZO' are. These values were introduced in commits by hpa: 77d1a4999502 ("x86, boot: make symbols from the main vmlinux available") 37ba7ab5e33c ("x86, boot: make kernel_alignment adjustable; new bzImage fields") Specifically: All names prefixed with 'VO_': - relate to the uncompressed kernel image - the size of the VO image is: VO__end-VO__text ("VO_INIT_SIZE" define) All names prefixed with 'ZO_': - relate to the bootable compressed kernel image (boot/compressed/vmlinux), which is composed of the following memory areas: - head text - compressed kernel (VO image and relocs table) - decompressor code - the size of the ZO image is: ZO__end - ZO_startup_32 ("ZO_INIT_SIZE" define, though see below) The 'INIT_SIZE' value is used to find the larger of the two image sizes: #define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset) #define VO_INIT_SIZE (VO__end - VO__text) #if ZO_INIT_SIZE > VO_INIT_SIZE # define INIT_SIZE ZO_INIT_SIZE #else # define INIT_SIZE VO_INIT_SIZE #endif The current code uses extract_offset to decide where to position the copied ZO (i.e. ZO starts at extract_offset). (This is why ZO_INIT_SIZE currently includes the extract_offset.) Why does z_extract_offset exist? It's needed because we are trying to minimize the amount of RAM used for the whole act of creating an uncompressed, executable, properly relocation-linked kernel image in system memory. We do this so that kernels can be booted on even very small systems. To achieve the goal of minimal memory consumption we have implemented an in-place decompression strategy: instead of cleanly separating the VO and ZO images and also allocating some memory for the decompression code's runtime needs, we instead create this elaborate layout of memory buffers where the output (decompressed) stream, as it progresses, overlaps with and destroys the input (compressed) stream. This can only be done safely if the ZO image is placed to the end of the VO range, plus a certain amount of safety distance to make sure that when the last bytes of the VO range are decompressed, the compressed stream pointer is safely beyond the end of the VO range. z_extract_offset is calculated in arch/x86/boot/compressed/mkpiggy.c during the build process, at a point when we know the exact compressed and uncompressed size of the kernel images and can calculate this safe minimum offset value. (Note that the mkpiggy.c calculation is not perfect, because we don't know the decompressor used at that stage, so the z_extract_offset calculation is necessarily imprecise and is mostly based on gzip internals - we'll improve that in the next patch.) When INIT_SIZE is bigger than VO_INIT_SIZE (uncommon but possible), the copied ZO occupies the memory from extract_offset to the end of decompression buffer. It overlaps with the soon-to-be-uncompressed kernel like this: |-----compressed kernel image------| V V 0 extract_offset +INIT_SIZE |-----------|---------------|-------------------------|--------| | | | | VO__text startup_32 of ZO VO__end ZO__end ^ ^ |-------uncompressed kernel image---------| When INIT_SIZE is equal to VO_INIT_SIZE (likely) there's still space left from end of ZO to the end of decompressing buffer, like below. |-compressed kernel image-| V V 0 extract_offset +INIT_SIZE |-----------|---------------|-------------------------|--------| | | | | VO__text startup_32 of ZO ZO__end VO__end ^ ^ |------------uncompressed kernel image-------------| To simplify calculations and avoid special cases, it is cleaner to always place the compressed kernel image in memory so that ZO__end is at the end of the decompression buffer, instead of placing t at the start of extract_offset as is currently done. This patch adds BP_init_size (which is the INIT_SIZE as passed in from the boot_params) into asm-offsets.c to make it visible to the assembly code. Then when moving the ZO, it calculates the starting position of the copied ZO (via BP_init_size and the ZO run size) so that the VO__end will be at the end of the decompression buffer. To make the position calculation safe, the end of ZO is page aligned (and a comment is added to the existing VO alignment for good measure). Signed-off-by: Yinghai Lu <[email protected]> [ Rewrote changelog and comments. ] Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Young <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] [ Rewrote the changelog some more. ] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-29x86/KASLR: Handle kernel relocations above 2G correctlyBaoquan He1-1/+1
When processing the relocation table, the offset used to calculate the relocation is an 'int'. This is sufficient for calculating the physical address of the relocs entry on 32-bit systems and on 64-bit systems when the relocation is under 2G. To handle relocations above 2G (seen in situations like kexec, netboot, etc), this offset needs to be calculated using a 'long' to avoid wrapping and miscalculating the relocation. Signed-off-by: Baoquan He <[email protected]> [ Rewrote the changelog. ] Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Young <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: Yinghai Lu <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
2016-04-28x86/boot: Rename overlapping memcpy() to memmove()Kees Cook1-2/+4
Instead of having non-standard memcpy() behavior, explicitly call the new function memmove(), make it available to the decompressors, and switch the two overlap cases (screen scrolling and ELF parsing) to use memmove(). Additionally documents the purpose of compressed/string.c. Suggested-by: Lasse Collin <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-22x86/KASLR: Warn when KASLR is disabledKees Cook1-3/+9
If KASLR is built in but not available at run-time (either due to the current conflict with hibernation, command-line request, or e820 parsing failures), announce the state explicitly. To support this, a new "warn" function is created, based on the existing "error" function. Suggested-by: Ingo Molnar <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-22x86/boot: Make memcpy() handle overlapsKees Cook1-3/+1
Two uses of memcpy() (screen scrolling and ELF parsing) were handling overlapping memory areas. While there were no explicitly noticed bugs here (yet), it is best to fix this so that the copying will always be safe. Instead of making a new memmove() function that might collide with other memmove() definitions in the decompressors, this just makes the compressed boot code's copy of memcpy() overlap-safe. Suggested-by: Lasse Collin <[email protected]> Reported-by: Yinghai Lu <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-22x86/boot: Clean up things used by decompressorsKees Cook1-4/+4
This rearranges the pieces needed to include the decompressor code in misc.c. It wasn't obvious why things were there, so a comment was added and definitions consolidated. Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-22x86/KASLR: Update description for decompressor worst case sizeBaoquan He1-81/+8
The comment that describes the analysis for the size of the decompressor code only took gzip into account (there are currently 6 other decompressors that could be used). The actual z_extract_offset calculation in code was already handling the correct maximum size, but this documentation hadn't been updated. This updates the documentation, fixes several typos, moves the comment to header.S, updates references, and adds a note at the end of the decompressor include list to remind us about updating the comment in the future. (Instead of moving the comment to mkpiggy.c, where the calculation is currently happening, it is being moved to header.S because the calculations in mkpiggy.c will be removed in favor of header.S calculations in a following patch, and it seemed like overkill to move the giant comment twice, especially when there's already reference to z_extract_offset in header.S.) Signed-off-by: Baoquan He <[email protected]> [ Rewrote changelog, cleaned up comment style, moved comments around. ] Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-19x86/KASLR: Clarify purpose of kaslr.cKees Cook1-1/+1
The name "choose_kernel_location" isn't specific enough, and doesn't describe the primary thing it does: choosing a random location. This patch renames it to "choose_random_location", and clarifies the what routines are contained in the kaslr.c source file. Suggested-by: Ingo Molnar <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-19x86/boot: Clarify purpose of functions in misc.cKees Cook1-4/+6
The function "decompress_kernel" now performs many more duties, so this patch renames it to "extract_kernel" and updates callers and comments. Additionally the file header comment for misc.c is improved to actually describe what is contained. Suggested-by: Ingo Molnar <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-19x86/boot: Rename "real_mode" to "boot_params"Kees Cook1-13/+14
The non-compressed boot code uses the (much more obvious) name "boot_params" for the global pointer to the x86 boot parameters. The compressed kernel loader code, though, was using the legacy name "real_mode". There is no need to have a different name, and changing it improves readability. Suggested-by: Ingo Molnar <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2016-04-19x86/KASLR: Remove unneeded boot_params argumentYinghai Lu1-1/+1
Since the boot_params can be found using the real_mode global variable, there is no need to pass around a pointer to it. This slightly simplifies the choose_kernel_location function and its callers. [kees: rewrote changelog, tracked file rename] Signed-off-by: Yinghai Lu <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2015-09-10lib/decompressors: use real out buf size for gunzip with kernelYinghai Lu1-1/+2
When loading x86 64bit kernel above 4GiB with patched grub2, got kernel gunzip error. | early console in decompress_kernel | decompress_kernel: | input: [0x807f2143b4-0x807ff61aee] | output: [0x807cc00000-0x807f3ea29b] 0x027ea29c: output_len | boot via startup_64 | KASLR using RDTSC... | new output: [0x46fe000000-0x470138cfff] 0x0338d000: output_run_size | decompress: [0x46fe000000-0x47007ea29b] <=== [0x807f2143b4-0x807ff61aee] | | Decompressing Linux... gz... | | uncompression error | | -- System halted the new buffer is at 0x46fe000000ULL, decompressor_gzip is using 0xffffffb901ffffff as out_len. gunzip in lib/zlib_inflate/inflate.c cap that len to 0x01ffffff and decompress fails later. We could hit this problem with crashkernel booting that uses kexec loading kernel above 4GiB. We have decompress_* support: 1. inbuf[]/outbuf[] for kernel preboot. 2. inbuf[]/flush() for initramfs 3. fill()/flush() for initrd. This bug only affect kernel preboot path that use outbuf[]. Add __decompress and take real out_buf_len for gunzip instead of guessing wrong buf size. Fixes: 1431574a1c4 (lib/decompressors: fix "no limit" output buffer length) Signed-off-by: Yinghai Lu <[email protected]> Cc: Alexandre Courbot <[email protected]> Cc: Jon Medhurst <[email protected]> Cc: Stephen Warren <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2015-07-07x86/boot: Add hex output for debuggingKees Cook1-0/+24
This is useful for reporting various addresses or other values while debugging early boot, for example, the recent kernel image size vs kernel run size. For example, when CONFIG_X86_VERBOSE_BOOTUP is set, this is now visible at boot time: early console in setup code early console in decompress_kernel input_data: 0x0000000001e1526e input_len: 0x0000000000732236 output: 0x0000000001000000 output_len: 0x0000000001535640 run_size: 0x00000000021fb000 KASLR using RDTSC... Signed-off-by: Kees Cook <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Jan Beulich <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Joe Perches <[email protected]> Cc: Josh Triplett <[email protected]> Cc: Junjie Mao <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2015-04-03x86/mm/KASLR: Propagate KASLR status to kernel properBorislav Petkov1-1/+4
Commit: e2b32e678513 ("x86, kaslr: randomize module base load address") made module base address randomization unconditional and didn't regard disabled KKASLR due to CONFIG_HIBERNATION and command line option "nokaslr". For more info see (now reverted) commit: f47233c2d34f ("x86/mm/ASLR: Propagate base load address calculation") In order to propagate KASLR status to kernel proper, we need a single bit in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the top-down allocated bits for bits supposed to be used by the bootloader. Originally-From: Jiri Kosina <[email protected]> Suggested-by: H. Peter Anvin <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Cc: Kees Cook <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
2015-03-16Revert "x86/mm/ASLR: Propagate base load address calculation"Borislav Petkov1-2/+1
This reverts commit: f47233c2d34f ("x86/mm/ASLR: Propagate base load address calculation") The main reason for the revert is that the new boot flag does not work at all currently, and in order to make this work, we need non-trivial changes to the x86 boot code which we didn't manage to get done in time for merging. And even if we did, they would've been too risky so instead of rushing things and break booting 4.1 on boxes left and right, we will be very strict and conservative and will take our time with this to fix and test it properly. Reported-by: Yinghai Lu <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Baoquan He <[email protected]> Cc: H. Peter Anvin <[email protected] Cc: Jiri Kosina <[email protected]> Cc: Josh Triplett <[email protected]> Cc: Junjie Mao <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Matt Fleming <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
2015-02-19x86/mm/ASLR: Propagate base load address calculationJiri Kosina1-1/+2
Commit: e2b32e678513 ("x86, kaslr: randomize module base load address") makes the base address for module to be unconditionally randomized in case when CONFIG_RANDOMIZE_BASE is defined and "nokaslr" option isn't present on the commandline. This is not consistent with how choose_kernel_location() decides whether it will randomize kernel load base. Namely, CONFIG_HIBERNATION disables kASLR (unless "kaslr" option is explicitly specified on kernel commandline), which makes the state space larger than what module loader is looking at. IOW CONFIG_HIBERNATION && CONFIG_RANDOMIZE_BASE is a valid config option, kASLR wouldn't be applied by default in that case, but module loader is not aware of that. Instead of fixing the logic in module.c, this patch takes more generic aproach. It introduces a new bootparam setup data_type SETUP_KASLR and uses that to pass the information whether kaslr has been applied during kernel decompression, and sets a global 'kaslr_enabled' variable accordingly, so that any kernel code (module loading, livepatching, ...) can make decisions based on its value. x86 module loader is converted to make use of this flag. Signed-off-by: Jiri Kosina <[email protected]> Acked-by: Kees Cook <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Link: https://lkml.kernel.org/r/[email protected] [ Always dump correct kaslr status when panicking ] Signed-off-by: Borislav Petkov <[email protected]>
2015-01-20x86, boot: Skip relocs when load address unchangedKees Cook1-1/+8
On 64-bit, relocation is not required unless the load address gets changed. Without this, relocations do unexpected things when the kernel is above 4G. Reported-by: Baoquan He <[email protected]> Signed-off-by: Kees Cook <[email protected]> Tested-by: Thomas D. <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: Jan Beulich <[email protected]> Cc: Junjie Mao <[email protected]> Cc: Andi Kleen <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]>
2014-12-10Merge branch 'x86-boot-for-linus' of ↵Linus Torvalds1-1/+13
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot and percpu updates from Ingo Molnar: "This tree contains a bootable images documentation update plus three slightly misplaced x86/asm percpu changes/optimizations" * 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86-64: Use RIP-relative addressing for most per-CPU accesses x86-64: Handle PC-relative relocations on per-CPU data x86: Convert a few more per-CPU items to read-mostly ones x86, boot: Document intermediates more clearly
2014-11-04x86-64: Handle PC-relative relocations on per-CPU dataJan Beulich1-1/+13
This is in preparation of using RIP-relative addressing in many of the per-CPU accesses. Signed-off-by: Jan Beulich <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]>
2014-11-01x86, kaslr: Prevent .bss from overlaping initrdJunjie Mao1-3/+10
When choosing a random address, the current implementation does not take into account the reversed space for .bss and .brk sections. Thus the relocated kernel may overlap other components in memory. Here is an example of the overlap from a x86_64 kernel in qemu (the ranges of physical addresses are presented): Physical Address 0x0fe00000 --+--------------------+ <-- randomized base / | relocated kernel | vmlinux.bin | (from vmlinux.bin) | 0x1336d000 (an ELF file) +--------------------+-- \ | | \ 0x1376d870 --+--------------------+ | | relocs table | | 0x13c1c2a8 +--------------------+ .bss and .brk | | | 0x13ce6000 +--------------------+ | | | / 0x13f77000 | initrd |-- | | 0x13fef374 +--------------------+ The initrd image will then be overwritten by the memset during early initialization: [ 1.655204] Unpacking initramfs... [ 1.662831] Initramfs unpacking failed: junk in compressed archive This patch prevents the above situation by requiring a larger space when looking for a random kernel base, so that existing logic can effectively avoids the overlap. [kees: switched to perl to avoid hex translation pain in mawk vs gawk] [kees: calculated overlap without relocs table] Fixes: 82fa9637a2 ("x86, kaslr: Select random position from e820 maps") Reported-by: Fengguang Wu <[email protected]> Signed-off-by: Junjie Mao <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Josh Triplett <[email protected]> Cc: Matt Fleming <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: Andi Kleen <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]>
2014-05-05asmlinkage, x86: Add explicit __visible to arch/x86/*Andi Kleen1-1/+1
As requested by Linus add explicit __visible to the asmlinkage users. This marks all functions visible to assembler. Tree sweep for arch/x86/* Signed-off-by: Andi Kleen <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]>
2014-03-19x86, boot: Move memset() definition in compressed/string.cVivek Goyal1-13/+7
Currently compressed/misc.c needs to link against memset(). I think one of the reasons of this need is inclusion of various header files which define static inline functions and use memset() inside these. For example, include/linux/bitmap.h I think trying to include "../string.h" and using builtin version of memset does not work because by the time "#define memset" shows up, it is too late. Some other header file has already used memset() and expects to find a definition during link phase. Currently we have a C definitoin of memset() in misc.c. Move it to compressed/string.c so that others can use it if need be. Signed-off-by: Vivek Goyal <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]>
2014-03-19x86, boot: Move optimized memcpy() 32/64 bit versions to compressed/string.cVivek Goyal1-30/+1
Move optimized versions of memcpy to compressed/string.c This will allow any other code to use these functions too if need be in future. Again trying to put definition in a common place instead of hiding it in misc.c Signed-off-by: Vivek Goyal <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]>
2013-10-13x86, kaslr: Select random position from e820 mapsKees Cook1-8/+2
Counts available alignment positions across all e820 maps, and chooses one randomly for the new kernel base address, making sure not to collide with unsafe memory areas. Signed-off-by: Kees Cook <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]>
2013-10-13x86, kaslr: Return location from decompress_kernelKees Cook1-2/+6
This allows decompress_kernel to return a new location for the kernel to be relocated to. Additionally, enforces CONFIG_PHYSICAL_START as the minimum relocation position when building with CONFIG_RELOCATABLE. With CONFIG_RANDOMIZE_BASE set, the choose_kernel_location routine will select a new location to decompress the kernel, though here it is presently a no-op. The kernel command line option "nokaslr" is introduced to bypass these routines. Signed-off-by: Kees Cook <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]>
2013-08-07x86, relocs: Move ELF relocation handling to CKees Cook1-1/+76
Moves the relocation handling into C, after decompression. This requires that the decompressed size is passed to the decompression routine as well so that relocations can be found. Only kernels that need relocation support will use the code (currently just x86_32), but this is laying the ground work for 64-bit using it in support of KASLR. Based on work by Neill Clift and Michael Davidson. Signed-off-by: Kees Cook <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Acked-by: Zhang Yanfei <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2013-07-09arm: add support for LZ4-compressed kernelKyungsik Lee1-0/+4
Integrates the LZ4 decompression code to the arm pre-boot code. Signed-off-by: Kyungsik Lee <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Russell King <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Florian Fainelli <[email protected]> Cc: Yann Collet <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2013-01-29x86, boot: Sanitize boot_params if not zeroed on creationH. Peter Anvin1-0/+2
Use the new sentinel field to detect bootloaders which fail to follow protocol and don't initialize fields in struct boot_params that they do not explicitly initialize to zero. Based on an original patch and research by Yinghai Lu. Changed by hpa to be invoked both in the decompression path and in the kernel proper; the latter for the case where a bootloader takes over decompression. Originally-by: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]>
2012-07-21x86, boot: Removed unused debug flag and set codeJoe Millenbach1-4/+0
As we're no longer using the flag we don't need to extract the value from the command line and store it. This is a step towards removing command line parameter code. Signed-off-by: Joe Millenbach <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Gokul Caushik <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2012-07-21x86, boot: Switch output functions from command-line flags to conditional ↵Joe Millenbach1-11/+1
compilation Changed putstr flagging from parameter to conditional compilation for puts, debug_putstr, and error_putstr. This allows for space savings since most configurations won't use this feature. Signed-off-by: Joe Millenbach <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Gokul Caushik <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2012-07-21x86, boot: Changed error putstr path to match new debug_putstr formatJoe Millenbach1-3/+3
For consistency we changed the error output path to match the new debug path. Signed-off-by: Joe Millenbach <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Gokul Caushik <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2012-07-21x86, boot: Wrap debug printing in a new debug_putstr functionJoe Millenbach1-8/+10
Change all instances of if (debug) putstr(...) to a new debug_putstr(...). This allows a future change to conditionally stub out debug_putstr to save space. Signed-off-by: Joe Millenbach <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Gokul Caushik <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2012-07-21x86, boot: Removed quiet flag and switched quiet output to debug flagJoe Millenbach1-6/+3
There are only 3 uses of the quiet flag and they all protect output that is only useful for debugging the stub, therefore we switched to using the debug flag for all extra output. Signed-off-by: Joe Millenbach <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Gokul Caushik <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2012-01-26x86/boot-image: Don't leak phdrs in arch/x86/boot/compressed/misc.c::Parse_elf()Jesper Juhl1-0/+2
We allocate memory with malloc(), but neglect to free it before the variable 'phdrs' goes out of scope --> leak. Signed-off-by: Jesper Juhl <[email protected]> Link: http://lkml.kernel.org/r/[email protected] [ Mostly harmless. ] Signed-off-by: Ingo Molnar <[email protected]>
2011-01-13x86: support XZ-compressed kernelLasse Collin1-0/+4
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 <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Alain Knaff <[email protected]> Cc: Albin Tonnerre <[email protected]> Cc: Phillip Lougher <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2010-12-16x86-32: Make sure we can map all of lowmem if we need toH. Peter Anvin1-1/+1
A relocatable kernel can be anywhere in lowmem -- and in the case of a kdump kernel, is likely to be fairly high. Since the early page tables map everything from address zero up we need to make sure we allocate enough brk that we can map all of lowmem if we need to. Reported-by: Stanislaw Gruszka <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]> Tested-by: Yinghai Lu <[email protected]> LKML-Reference: <[email protected]>
2010-10-07x86, setup: Use string copy operation to optimze copy in kernel compressionZhao Yakui1-6/+23
The kernel decompression code parses the ELF header and then copies the segment to the corresponding destination. Currently it uses slow byte-copy code. This patch makes it use the string copy operations instead. In the test the copy performance can be improved very significantly after using the string copy operation mechanism. 1. The copy time can be reduced from 150ms to 20ms on one Atom machine 2. The copy time can be reduced about 80% on another machine The time is reduced from 7ms to 1.5ms when using 32-bit kernel. The time is reduced from 10ms to 2ms when using 64-bit kernel. Signed-off-by: Zhao Yakui <[email protected]> LKML-Reference: <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2010-08-02x86, setup: enable early console output from the decompressorYinghai Lu1-23/+33
This enables the decompressor output to be seen on the serial console. Most of the code is shared with the regular boot code. We could add printf to the decompressor if needed, but currently there is no sufficiently compelling user. -v2: define BOOT_BOOT_H to avoid include boot.h -v3: early_serial_base need to be static in misc.c ? -v4: create seperate string.c printf.c cmdline.c early_serial_console.c after hpa's patch that allow global variables in compressed/misc stage -v5: remove printf.c related Signed-off-by: Yinghai Lu <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2010-02-28Merge branch 'x86-setup-for-linus' of ↵Linus Torvalds1-2/+0
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-setup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, setup: Don't skip mode setting for the standard VGA modes x86-64, setup: Inhibit decompressor output if video info is invalid x86, setup: When restoring the screen, update boot_params.screen_info
2010-02-18x86-64, setup: Inhibit decompressor output if video info is invalidH. Peter Anvin1-2/+0
Inhibit output from the kernel decompressor if the video information is invalid. This was already the case for 32 bits, make 64 bits match. Signed-off-by: H. Peter Anvin <[email protected]> LKML-Reference: <tip-*@git.kernel.org>
2010-02-05x86: Clean up mem*io functions.Brian Gerst1-9/+4
Iomem has no special significance on x86. Use the standard mem* functions instead of trying to call other versions. Some fixups are needed to match the function prototypes. Signed-off-by: Brian Gerst <[email protected]> LKML-Reference: <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2010-01-11x86: add support for LZO-compressed kernelsAlbin Tonnerre1-0/+4
The necessary changes to the x86 Kconfig and boot/compressed to allow the use of this new compression method Signed-off-by: Albin Tonnerre <[email protected]> Acked-by: H. Peter Anvin <[email protected]> Tested-by: Wu Zhangjin <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Thomas Gleixner <[email protected]> Tested-by: Russell King <[email protected]> Acked-by: Russell King <[email protected]> Cc: Ralf Baechle <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2009-05-12x86, boot: correct sanity checks in boot/compressed/misc.cH. Peter Anvin1-7/+5
arch/x86/boot/compressed/misc.c contains several sanity checks on the output address. Correct constraints that are no longer correct: - the alignment test should be MIN_KERNEL_ALIGN on both 32 and 64 bits. - the 64 bit maximum address was set to 2^40, which was the limit of one specific x86-64 implementation. Change the test to 2^46, the current Linux limit, and at least try to test the end rather than the beginning. - for non-relocatable kernels, test against LOAD_PHYSICAL_ADDR on both 32 and 64 bits. [ Impact: fix potential boot failure due to invalid tests ] Signed-off-by: H. Peter Anvin <[email protected]>
2009-01-04bzip2/lzma: x86 kernel compression supportAlain Knaff1-104/+14
Impact: Replaces x86 kernel decompressor with new code This is the third part of the bzip2/lzma patch The bzip patch is based on an idea by Christian Ludwig, includes support for compressing the kernel with bzip2 or lzma rather than gzip. Both compressors give smaller sizes than gzip. Lzma's decompresses faster than bzip2. It also supports ramdisks and initramfs' compressed using these two compressors. The functionality has been successfully used for a couple of years by the udpcast project This version applies to "tip" kernel 2.6.28 This part contains: - support for new bzip2 and lzma kernel compression for x86 Signed-off-by: Alain Knaff <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
2008-10-22x86: Fix ASM_X86__ header guardsH. Peter Anvin1-1/+1
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: H. Peter Anvin <[email protected]>
2008-10-06Merge branches 'x86/alternatives', 'x86/cleanups', 'x86/commandline', ↵Ingo Molnar1-4/+6
'x86/crashdump', 'x86/debug', 'x86/defconfig', 'x86/doc', 'x86/exports', 'x86/fpu', 'x86/gart', 'x86/idle', 'x86/mm', 'x86/mtrr', 'x86/nmi-watchdog', 'x86/oprofile', 'x86/paravirt', 'x86/reboot', 'x86/sparse-fixes', 'x86/tsc', 'x86/urgent' and 'x86/vmalloc' into x86-v28-for-linus-phase1
2008-08-15x86: coding style fixes to arch/x86/boot/compressed/misc.cPaolo Ciarrocchi1-4/+6
Before: total: 4 errors, 6 warnings, 439 lines checked After: total: 1 errors, 5 warnings, 441 lines checked Before -#include <asm/io.h> +#include <linux/io.h> paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/misc.o.* 8b2394e1fe519a9542e9a7e3e7b69c39 /tmp/misc.o.after 8b2394e1fe519a9542e9a7e3e7b69c39 /tmp/misc.o.before After -#include <asm/io.h> +#include <linux/io.h> paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/misc.o.* 59a2d264284be5e72b5af4f3a8ccfb47 /tmp/misc.o.after 8b2394e1fe519a9542e9a7e3e7b69c39 /tmp/misc.o.before Signed-off-by: Paolo Ciarrocchi <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
2008-07-26Merge branch 'linus' into x86/header-guardsIngo Molnar1-39/+0
Conflicts: include/asm-x86/gpio.h include/asm-x86/ide.h Signed-off-by: Ingo Molnar <[email protected]>
2008-07-25inflate: refactor inflate malloc codeThomas Petazzoni1-39/+0
Inflate requires some dynamic memory allocation very early in the boot process and this is provided with a set of four functions: malloc/free/gzip_mark/gzip_release. The old inflate code used a mark/release strategy rather than implement free. This new version instead keeps a count on the number of outstanding allocations and when it hits zero, it resets the malloc arena. This allows removing all the mark and release implementations and unifying all the malloc/free implementations. The architecture-dependent code must define two addresses: - free_mem_ptr, the address of the beginning of the area in which allocations should be made - free_mem_end_ptr, the address of the end of the area in which allocations should be made. If set to 0, then no check is made on the number of allocations, it just grows as much as needed The architecture-dependent code can also provide an arch_decomp_wdog() function call. This function will be called several times during the decompression process, and allow to notify the watchdog that the system is still running. If an architecture provides such a call, then it must define ARCH_HAS_DECOMP_WDOG so that the generic inflate code calls arch_decomp_wdog(). Work initially done by Matt Mackall, updated to a recent version of the kernel and improved by me. [[email protected]: coding-style fixes] Signed-off-by: Thomas Petazzoni <[email protected]> Cc: Matt Mackall <[email protected]> Cc: Richard Henderson <[email protected]> Cc: Ivan Kokshaysky <[email protected]> Cc: Mikael Starvik <[email protected]> Cc: Jesper Nilsson <[email protected]> Cc: Haavard Skinnemoen <[email protected]> Cc: David Howells <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Andi Kleen <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Acked-by: Paul Mundt <[email protected]> Acked-by: Yoshinori Sato <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2008-07-22x86: consolidate header guardsVegard Nossum1-1/+1
This patch consolidates the header guard names which are also used externally, i.e. in .c files. Signed-off-by: Vegard Nossum <[email protected]>