linux-toradex.git/arch/x86/boot/compressed, branch v4.4.35

x86/build: Build compressed x86 kernels as PIE

2016-10-20T08:00:47+00:00

commit 6d92bc9d483aa1751755a66fee8fb39dffb088c0 upstream.

The 32-bit x86 assembler in binutils 2.26 will generate R_386_GOT32X
relocation to get the symbol address in PIC.  When the compressed x86
kernel isn't built as PIC, the linker optimizes R_386_GOT32X relocations
to their fixed symbol addresses.  However, when the compressed x86
kernel is loaded at a different address, it leads to the following
load failure:

  Failed to allocate space for phdrs

during the decompression stage.

If the compressed x86 kernel is relocatable at run-time, it should be
compiled with -fPIE, instead of -fPIC, if possible and should be built as
Position Independent Executable (PIE) so that linker won't optimize
R_386_GOT32X relocation to its fixed symbol address.

Older linkers generate R_386_32 relocations against locally defined
symbols, _bss, _ebss, _got and _egot, in PIE.  It isn't wrong, just less
optimal than R_386_RELATIVE.  But the x86 kernel fails to properly handle
R_386_32 relocations when relocating the kernel.  To generate
R_386_RELATIVE relocations, we mark _bss, _ebss, _got and _egot as
hidden in both 32-bit and 64-bit x86 kernels.

To build a 64-bit compressed x86 kernel as PIE, we need to disable the
relocation overflow check to avoid relocation overflow errors. We do
this with a new linker command-line option, -z noreloc-overflow, which
got added recently:

 commit 4c10bbaa0912742322f10d9d5bb630ba4e15dfa7
 Author: H.J. Lu 
 Date:   Tue Mar 15 11:07:06 2016 -0700

    Add -z noreloc-overflow option to x86-64 ld

    Add -z noreloc-overflow command-line option to the x86-64 ELF linker to
    disable relocation overflow check.  This can be used to avoid relocation
    overflow check if there will be no dynamic relocation overflow at
    run-time.

The 64-bit compressed x86 kernel is built as PIE only if the linker supports
-z noreloc-overflow.  So far 64-bit relocatable compressed x86 kernel
boots fine even when it is built as a normal executable.

Signed-off-by: H.J. Lu 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
[ Edited the changelog and comments. ]
Signed-off-by: Ingo Molnar 
Cc: Paul Bolle 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into core/efi

2015-10-14T14:51:34+00:00

Pull v4.4 EFI updates from Matt Fleming:

  - Make the EFI System Resource Table (ESRT) driver explicitly
    non-modular by ripping out the module_* code since Kconfig doesn't
    allow it to be built as a module anyway. (Paul Gortmaker)

  - Make the x86 efi=debug kernel parameter, which enables EFI debug
    code and output, generic and usable by arm64. (Leif Lindholm)

  - Add support to the x86 EFI boot stub for 64-bit Graphics Output
    Protocol frame buffer addresses. (Matt Fleming)

  - Detect when the UEFI v2.5 EFI_PROPERTIES_TABLE feature is enabled
    in the firmware and set an efi.flags bit so the kernel knows when
    it can apply more strict runtime mapping attributes - Ard Biesheuvel

  - Auto-load the efi-pstore module on EFI systems, just like we
    currently do for the efivars module. (Ben Hutchings)

  - Add "efi_fake_mem" kernel parameter which allows the system's EFI
    memory map to be updated with additional attributes for specific
    memory ranges. This is useful for testing the kernel code that handles
    the EFI_MEMORY_MORE_RELIABLE memmap bit even if your firmware
    doesn't include support. (Taku Izumi)

Note: there is a semantic conflict between the following two commits:

  8a53554e12e9 ("x86/efi: Fix multiple GOP device support")
  ae2ee627dc87 ("efifb: Add support for 64-bit frame buffer addresses")

I fixed up the interaction in the merge commit, changing the type of
current_fb_base from u32 to u64.

Signed-off-by: Ingo Molnar

x86/efi: Fix multiple GOP device support

2015-10-14T14:02:43+00:00

When multiple GOP devices exists, but none of them implements
ConOut, the code should just choose the first GOP (according to
the comments). But currently 'fb_base' will refer to the last GOP,
while other parameters to the first GOP, which will likely
result in a garbled display.

I can reliably reproduce this bug using my ASRock Z87M Extreme4
motherboard with CSM and integrated GPU disabled, and two PCIe
video cards (NVidia GT640 and GTX980), booting from efi-stub
(booting from grub works fine).  On the primary display the
ASRock logo remains and on the secondary screen it is garbled
up completely.

Signed-off-by: Kővágó, Zoltán 
Signed-off-by: Matt Fleming 
Cc: 
Cc: Linus Torvalds 
Cc: Matthew Garrett 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1444659236-24837-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar

efifb: Add support for 64-bit frame buffer addresses

2015-10-12T13:20:06+00:00

The EFI Graphics Output Protocol uses 64-bit frame buffer addresses
but these get truncated to 32-bit by the EFI boot stub when storing
the address in the 'lfb_base' field of 'struct screen_info'.

Add a 'ext_lfb_base' field for the upper 32-bits of the frame buffer
address and set VIDEO_TYPE_CAPABILITY_64BIT_BASE when the field is
useable.

It turns out that the reason no one has required this support so far
is that there's actually code in tianocore to "downgrade" PCI
resources that have option ROMs and 64-bit BARS from 64-bit to 32-bit
to cope with legacy option ROMs that can't handle 64-bit addresses.
The upshot is that basically all GOP devices in the wild use a 32-bit
frame buffer address.

Still, it is possible to build firmware that uses a full 64-bit GOP
frame buffer address. Chad did, which led to him reporting this issue.

Add support in anticipation of GOP devices using 64-bit addresses more
widely, and so that efifb works out of the box when that happens.

Reported-by: Chad Page 
Cc: Pete Hawkins 
Acked-by: Peter Jones 
Cc: Matthew Garrett 
Cc: Geert Uytterhoeven 
Signed-off-by: Matt Fleming

lib/decompressors: use real out buf size for gunzip with kernel

2015-09-10T20:29:01+00:00

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 
Cc: Alexandre Courbot 
Cc: Jon Medhurst 
Cc: Stephen Warren 
Cc: "H. Peter Anvin" 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-09-01T16:04:31+00:00

Pull x86 boot updates from Ingo Molnar:
 "The main x86 bootup related changes in this cycle were:

   - more boot time optimizations.  (Len Brown)

   - implement hex output to allow the debugging of early bootup
     parameters.  (Kees Cook)

   - remove obsolete MCA leftovers.  (Paolo Pisati)"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smpboot: Remove APIC.wait_for_init_deassert and atomic init_deasserted
  x86/smpboot: Remove SIPI delays from cpu_up()
  x86/smpboot: Remove udelay(100) when polling cpu_callin_map
  x86/smpboot: Remove udelay(100) when polling cpu_initialized_map
  x86/boot: Obsolete the MCA sys_desc_table
  x86/boot: Add hex output for debugging

Merge tag 'v4.2-rc7' into x86/boot, to refresh the branch before merging new changes

2015-08-17T08:41:59+00:00

Signed-off-by: Ingo Molnar

Merge branch 'x86/urgent' into x86/asm, before applying dependent patches

2015-07-31T08:23:35+00:00

Signed-off-by: Ingo Molnar

x86/efi: Use all 64 bit of efi_memmap in setup_e820()

2015-07-30T17:07:10+00:00

The efi_info structure stores low 32 bits of memory map
in efi_memmap and high 32 bits in efi_memmap_hi.

While constructing pointer in the setup_e820(), need
to take into account all 64 bit of the pointer.

It is because on 64bit machine the function
efi_get_memory_map() may return full 64bit pointer and before
the patch that pointer was truncated.

The issue is triggered on Parallles virtual machine and
fixed with this patch.

Signed-off-by: Dmitry Skorodumov 
Cc: Denis V. Lunev 
Cc: 
Signed-off-by: Matt Fleming

x86/boot: Obsolete the MCA sys_desc_table

2015-07-21T08:55:11+00:00

The kernel does not support the MCA bus anymroe, so mark sys_desc_table
as obsolete: remove any reference from the code together with the remaining
of MCA logic.

bloat-o-meter output:

  add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-55 (-55)
  function                                     old     new   delta
  i386_start_kernel                            128     119      -9
  setup_arch                                  1421    1375     -46

Signed-off-by: Paolo Pisati 
Cc: Josh Triplett 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1437409430-8491-1-git-send-email-p.pisati@gmail.com
Signed-off-by: Ingo Molnar