1. 19 2月, 2015 1 次提交
  2. 02 11月, 2014 1 次提交
    • J
      x86, kaslr: Prevent .bss from overlaping initrd · e6023367
      Junjie Mao 提交于
      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: 82fa9637 ("x86, kaslr: Select random position from e820 maps")
      Reported-by: NFengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: NJunjie Mao <eternal.n08@gmail.com>
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Cc: Josh Triplett <josh@joshtriplett.org>
      Cc: Matt Fleming <matt.fleming@intel.com>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: stable@vger.kernel.org
      Link: http://lkml.kernel.org/r/1414762838-13067-1-git-send-email-eternal.n08@gmail.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      e6023367
  3. 23 9月, 2014 1 次提交
  4. 09 9月, 2014 1 次提交
    • M
      x86/efi: Fixup GOT in all boot code paths · 9cb0e394
      Matt Fleming 提交于
      Maarten reported that his Macbook pro 8.2 stopped booting after commit
      f23cf8bd ("efi/x86: efistub: Move shared dependencies to
      <asm/efi.h>"), the main feature of which is changing the visibility of
      symbol 'efi_early' from local to global.
      
      By making 'efi_early' global we end up requiring an entry in the Global
      Offset Table. Unfortunately, while we do include code to fixup GOT
      entries in the early boot code, it's only called after we've executed
      the EFI boot stub.
      
      What this amounts to is that references to 'efi_early' in the EFI boot
      stub don't point to the correct place.
      
      Since we've got multiple boot entry points we need to be prepared to
      fixup the GOT in multiple places, while ensuring that we never do it
      more than once, otherwise the GOT entries will still point to the wrong
      place.
      Reported-by: NMaarten Lankhorst <maarten.lankhorst@canonical.com>
      Tested-by: NMaarten Lankhorst <maarten.lankhorst@canonical.com>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      9cb0e394
  5. 17 4月, 2014 1 次提交
    • M
      x86/efi: Delete most of the efi_call* macros · 62fa6e69
      Matt Fleming 提交于
      We really only need one phys and one virt function call, and then only
      one assembly function to make firmware calls.
      
      Since we are not using the C type system anyway, we're not really losing
      much by deleting the macros apart from no longer having a check that
      we are passing the correct number of parameters. The lack of duplicated
      code seems like a worthwhile trade-off.
      
      Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
      Cc: Borislav Petkov <bp@suse.de>
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      62fa6e69
  6. 11 4月, 2014 1 次提交
  7. 05 3月, 2014 4 次提交
    • M
      x86/boot: Fix non-EFI build · 3db4cafd
      Matt Fleming 提交于
      The kbuild test robot reported the following errors, introduced with
      commit 54b52d87 ("x86/efi: Build our own EFI services pointer
      table"),
      
       arch/x86/boot/compressed/head_32.o: In function `efi32_config':
      >> (.data+0x58): undefined reference to `efi_call_phys'
      
       arch/x86/boot/compressed/head_64.o: In function `efi64_config':
      >> (.data+0x90): undefined reference to `efi_call6'
      
      Wrap the efi*_config structures in #ifdef CONFIG_EFI_STUB so that we
      don't make references to EFI functions if they're not compiled in.
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      3db4cafd
    • M
      x86/boot: Don't overwrite cr4 when enabling PAE · 108d3f44
      Matt Fleming 提交于
      Some EFI firmware makes use of the FPU during boottime services and
      clearing X86_CR4_OSFXSR by overwriting %cr4 causes the firmware to
      crash.
      
      Add the PAE bit explicitly instead of trashing the existing contents,
      leaving the rest of the bits as the firmware set them.
      
      Cc: H. Peter Anvin <hpa@zytor.com>
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      108d3f44
    • M
      x86/efi: Firmware agnostic handover entry points · b8ff87a6
      Matt Fleming 提交于
      The EFI handover code only works if the "bitness" of the firmware and
      the kernel match, i.e. 64-bit firmware and 64-bit kernel - it is not
      possible to mix the two. This goes against the tradition that a 32-bit
      kernel can be loaded on a 64-bit BIOS platform without having to do
      anything special in the boot loader. Linux distributions, for one thing,
      regularly run only 32-bit kernels on their live media.
      
      Despite having only one 'handover_offset' field in the kernel header,
      EFI boot loaders use two separate entry points to enter the kernel based
      on the architecture the boot loader was compiled for,
      
          (1) 32-bit loader: handover_offset
          (2) 64-bit loader: handover_offset + 512
      
      Since we already have two entry points, we can leverage them to infer
      the bitness of the firmware we're running on, without requiring any boot
      loader modifications, by making (1) and (2) valid entry points for both
      CONFIG_X86_32 and CONFIG_X86_64 kernels.
      
      To be clear, a 32-bit boot loader will always use (1) and a 64-bit boot
      loader will always use (2). It's just that, if a single kernel image
      supports (1) and (2) that image can be used with both 32-bit and 64-bit
      boot loaders, and hence both 32-bit and 64-bit EFI.
      
      (1) and (2) must be 512 bytes apart at all times, but that is already
      part of the boot ABI and we could never change that delta without
      breaking existing boot loaders anyhow.
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      b8ff87a6
    • M
      x86/efi: Build our own EFI services pointer table · 54b52d87
      Matt Fleming 提交于
      It's not possible to dereference the EFI System table directly when
      booting a 64-bit kernel on a 32-bit EFI firmware because the size of
      pointers don't match.
      
      In preparation for supporting the above use case, build a list of
      function pointers on boot so that callers don't have to worry about
      converting pointer sizes through multiple levels of indirection.
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      54b52d87
  8. 13 10月, 2013 1 次提交
  9. 08 8月, 2013 1 次提交
  10. 28 5月, 2013 1 次提交
  11. 02 3月, 2013 1 次提交
  12. 30 1月, 2013 3 次提交
  13. 28 1月, 2013 1 次提交
    • D
      x86, build: Dynamically find entry points in compressed startup code · 99f857db
      David Woodhouse 提交于
      We have historically hard-coded entry points in head.S just so it's easy
      to build the executable/bzImage headers with references to them.
      
      Unfortunately, this leads to boot loaders abusing these "known" addresses
      even when they are *explicitly* told that they "should look at the ELF
      header to find this address, as it may change in the future". And even
      when the address in question *has* actually been changed in the past,
      without fanfare or thought to compatibility.
      
      Thus we have bootloaders doing stunningly broken things like jumping
      to offset 0x200 in the kernel startup code in 64-bit mode, *hoping*
      that startup_64 is still there (it has moved at least once
      before). And hoping that it's actually a 64-bit kernel despite the
      fact that we don't give them any indication of that fact.
      
      This patch should hopefully remove the temptation to abuse internal
      addresses in future, where sternly worded comments have not sufficed.
      Instead of having hard-coded addresses and saying "please don't abuse
      these", we actually pull the addresses out of the ELF payload into
      zoffset.h, and make build.c shove them back into the right places in
      the bzImage header.
      
      Rather than including zoffset.h into build.c and thus having to rebuild
      the tool for every kernel build, we parse it instead. The parsing code
      is small and simple.
      
      This patch doesn't actually move any of the interesting entry points, so
      any offending bootloader will still continue to "work" after this patch
      is applied. For some version of "work" which includes jumping into the
      compressed payload and crashing, if the bzImage it's given is a 32-bit
      kernel. No change there then.
      
      [ hpa: some of the issues in the description are addressed or
        retconned by the 2.12 boot protocol.  This patch has been edited to
        only remove fixed addresses that were *not* thus retconned. ]
      Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
      Link: http://lkml.kernel.org/r/1358513837.2397.247.camel@shinybook.infradead.orgSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      Cc: Matt Fleming <matt.fleming@intel.com>
      99f857db
  14. 21 7月, 2012 1 次提交
    • M
      x86, efi: Handover Protocol · 9ca8f72a
      Matt Fleming 提交于
      As things currently stand, traditional EFI boot loaders and the EFI
      boot stub are carrying essentially the same initialisation code
      required to setup an EFI machine for booting a kernel. There's really
      no need to have this code in two places and the hope is that, with
      this new protocol, initialisation and booting of the kernel can be
      left solely to the kernel's EFI boot stub. The responsibilities of the
      boot loader then become,
      
         o Loading the kernel image from boot media
      
      File system code still needs to be carried by boot loaders for the
      scenario where the kernel and initrd files reside on a file system
      that the EFI firmware doesn't natively understand, such as ext4, etc.
      
         o Providing a user interface
      
      Boot loaders still need to display any menus/interfaces, for example
      to allow the user to select from a list of kernels.
      
      Bump the boot protocol number because we added the 'handover_offset'
      field to indicate the location of the handover protocol entry point.
      
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Peter Jones <pjones@redhat.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      Acked-and-Tested-by: NMatthew Garrett <mjg@redhat.com>
      Link: http://lkml.kernel.org/r/1342689828-16815-1-git-send-email-matt@console-pimps.orgSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
      9ca8f72a
  15. 17 4月, 2012 1 次提交
  16. 13 12月, 2011 1 次提交
    • M
      x86, efi: EFI boot stub support · 291f3632
      Matt Fleming 提交于
      There is currently a large divide between kernel development and the
      development of EFI boot loaders. The idea behind this patch is to give
      the kernel developers full control over the EFI boot process. As
      H. Peter Anvin put it,
      
      "The 'kernel carries its own stub' approach been very successful in
      dealing with BIOS, and would make a lot of sense to me for EFI as
      well."
      
      This patch introduces an EFI boot stub that allows an x86 bzImage to
      be loaded and executed by EFI firmware. The bzImage appears to the
      firmware as an EFI application. Luckily there are enough free bits
      within the bzImage header so that it can masquerade as an EFI
      application, thereby coercing the EFI firmware into loading it and
      jumping to its entry point. The beauty of this masquerading approach
      is that both BIOS and EFI boot loaders can still load and run the same
      bzImage, thereby allowing a single kernel image to work in any boot
      environment.
      
      The EFI boot stub supports multiple initrds, but they must exist on
      the same partition as the bzImage. Command-line arguments for the
      kernel can be appended after the bzImage name when run from the EFI
      shell, e.g.
      
      Shell> bzImage console=ttyS0 root=/dev/sdb initrd=initrd.img
      
      v7:
       - Fix checkpatch warnings.
      
      v6:
      
       - Try to allocate initrd memory just below hdr->inird_addr_max.
      
      v5:
      
       - load_options_size is UTF-16, which needs dividing by 2 to convert
         to the corresponding ASCII size.
      
      v4:
      
       - Don't read more than image->load_options_size
      
      v3:
      
       - Fix following warnings when compiling CONFIG_EFI_STUB=n
      
         arch/x86/boot/tools/build.c: In function ‘main’:
         arch/x86/boot/tools/build.c:138:24: warning: unused variable ‘pe_header’
         arch/x86/boot/tools/build.c:138:15: warning: unused variable ‘file_sz’
      
       - As reported by Matthew Garrett, some Apple machines have GOPs that
         don't have hardware attached. We need to weed these out by
         searching for ones that handle the PCIIO protocol.
      
       - Don't allocate memory if no initrds are on cmdline
       - Don't trust image->load_options_size
      
      Maarten Lankhorst noted:
       - Don't strip first argument when booted from efibootmgr
       - Don't allocate too much memory for cmdline
       - Don't update cmdline_size, the kernel considers it read-only
       - Don't accept '\n' for initrd names
      
      v2:
      
       - File alignment was too large, was 8192 should be 512. Reported by
         Maarten Lankhorst on LKML.
       - Added UGA support for graphics
       - Use VIDEO_TYPE_EFI instead of hard-coded number.
       - Move linelength assignment until after we've assigned depth
       - Dynamically fill out AddressOfEntryPoint in tools/build.c
       - Don't use magic number for GDT/TSS stuff. Requested by Andi Kleen
       - The bzImage may need to be relocated as it may have been loaded at
         a high address address by the firmware. This was required to get my
         macbook booting because the firmware loaded it at 0x7cxxxxxx, which
         triggers this error in decompress_kernel(),
      
      	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
      		error("Destination address too large");
      
      Cc: Mike Waychison <mikew@google.com>
      Cc: Matthew Garrett <mjg@redhat.com>
      Tested-by: NHenrik Rydberg <rydberg@euromail.se>
      Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      Link: http://lkml.kernel.org/r/1321383097.2657.9.camel@mfleming-mobl1.ger.corp.intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      291f3632
  17. 11 11月, 2010 1 次提交
  18. 03 8月, 2010 1 次提交
  19. 24 10月, 2009 1 次提交
  20. 19 9月, 2009 1 次提交
  21. 12 5月, 2009 3 次提交
  22. 09 5月, 2009 6 次提交
    • H
      x86, boot: determine compressed code offset at compile time · 02a884c0
      H. Peter Anvin 提交于
      Determine the compressed code offset (from the kernel runtime address)
      at compile time.  This allows some minor optimizations in
      arch/x86/boot/compressed/head_*.S, but more importantly it makes this
      value available to the build process, which will enable a future patch
      to export the necessary linear memory footprint into the bzImage
      header.
      
      [ Impact: cleanup, future patch enabling ]
      Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      02a884c0
    • H
      x86, boot: use appropriate rep string for move and clear · 36d3793c
      H. Peter Anvin 提交于
      In the pre-decompression code, use the appropriate largest possible
      rep movs and rep stos to move code and clear bss, respectively.  For
      reverse copy, do note that the initial values are supposed to be the
      address of the first (highest) copy datum, not one byte beyond the end
      of the buffer.
      
      rep strings are not necessarily the fastest way to perform these
      operations on all current processors, but are likely to be in the
      future, and perhaps more importantly, we want to encourage the
      architecturally right thing to do here.
      
      This also fixes a couple of trivial inefficiencies on 64 bits.
      
      [ Impact: trivial performance enhancement, increase code similarity ]
      Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      36d3793c
    • H
      x86, boot: set up the decompression stack as early as possible · 0a137736
      H. Peter Anvin 提交于
      Set up the decompression stack as soon as we know where it needs to
      go.  That way we have a full-service stack as soon as possible, rather
      than relying on the BP_scratch field.
      
      Note that the stack does need to be empty during bss zeroing (or
      else the stack needs to be moved out of the bss segment, which is also
      an option.)
      
      [ Impact: cleanup, minor paranoia ]
      Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      0a137736
    • H
      x86, boot: straighten out ranges to copy/zero in compressed/head*.S · 5b11f1ce
      H. Peter Anvin 提交于
      Both on 32 and 64 bits, we copy all the way up to the end of bss,
      except that on 64 bits there is a hack to avoid copying on top of the
      page tables.  There is no point in copying bss at all, especially
      since we are just about to zero it all anyway.
      
      To clean up and unify the handling, we now do:
      
        - copy from startup_32 to _bss.
        - zero from _bss to _ebss.
        - the _ebss symbol is aligned to an 8-byte boundary.
        - the page tables are moved to a separate section.
      
      Use _bss as the copy endpoint since _edata may be misaligned.
      
      [ Impact: cleanup, trivial performance improvement ]
      Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      5b11f1ce
    • H
      x86, boot: stylistic cleanups for boot/compressed/head_64.S · b40d68d5
      H. Peter Anvin 提交于
      Clean up style issues in arch/x86/boot/compressed/head_64.S.  This
      file had a lot fewer style issues than its 32-bit cousin, but the ones
      it has are worth fixing, especially since it makes the two files more
      similar.
      
      [ Impact: cleanup, no object code change ]
      Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      b40d68d5
    • H
      x86, boot: use BP_scratch in arch/x86/boot/compressed/head_*.S · bd2a3698
      H. Peter Anvin 提交于
      Use the BP_scratch symbol from asm-offsets.h instead of hard-coding
      the location.
      
      [ Impact: cleanup ]
      Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      bd2a3698
  23. 20 2月, 2009 1 次提交
  24. 14 2月, 2009 1 次提交
  25. 25 5月, 2008 1 次提交
  26. 20 4月, 2008 2 次提交
  27. 04 2月, 2008 1 次提交