Commit graph

422 commits

Author SHA1 Message Date
Leif Lindholm
c8e16df67f arm: Delete unused efi support from loader/arm
The 32-bit arm efi port now shares the 64-bit linux loader, so delete
the now unused bits from the 32-bit linux loader.

This in turn leaves the grub-core/kern/arm/efi/misc.c unused, so
delete that too.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 13:19:10 -04:00
Leif Lindholm
ba3da3c002 arm64/linux/loader: Rename functions and macros and move to common headers
In preparation for using the linux loader for 32-bit and 64-bit platforms,
rename grub_arm64*/GRUB_ARM64* to grub_armxx*/GRUB_ARMXX*.

Move prototypes for now-common functions to efi/efi.h.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 13:19:10 -04:00
Arindam Nath
8db0a305e4 i386/linux: Add support for ext_lfb_base
The EFI Graphics Output Protocol can return a 64-bit
linear frame buffer address in some firmware/BIOS
implementations. We currently only store the lower
32-bits in the lfb_base. This will eventually be
passed to Linux kernel and the efifb driver will
incorrectly interpret the framebuffer address as
32-bit address.

The Linux kernel has already added support to handle
64-bit linear framebuffer address in the efifb driver
since quite some time now.

This patch adds the support for 64-bit linear frame
buffer address in GRUB to address the above mentioned
scenario.

Signed-off-by: Arindam Nath <arindam.nath@amd.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 13:19:10 -04:00
Denis 'GNUtoo' Carikli
3c3ddc9b92 multiboot_elfxx.c: Fix compilation by fixing undeclared variable
Without that fix we have:
  In file included from ../../include/grub/command.h:25:0,
                   from ../../grub-core/loader/multiboot.c:30:
  ../../grub-core/loader/multiboot_elfxx.c: In function 'grub_multiboot_load_elf64':
  ../../grub-core/loader/multiboot_elfxx.c:130:28: error: 'relocatable' undeclared (first use in this function)
     "load_base_addr=0x%x\n", relocatable,

This happens due to mistake in the commit 14ec665
(mbi: Use per segment a separate relocator chunk).

So, let's fix it.

Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 13:19:10 -04:00
Leif Lindholm
5c6a46110d efi/fdt: Set address/size cells to 2 for empty tree
When booting an arm* system on UEFI with an empty device tree (currently
only when hardware description comes from ACPI), we don't currently set
default to 1 cell (32 bits).

Set both of these properties, to 2 cells (64 bits), to resolve issues
with kexec on some platforms.

This change corresponds with linux kernel commit ae8a442dfdc4
("efi/libstub/arm*: Set default address and size cells values for an empty dtb")
and ensures booting through grub does not behave differently from booting
the stub loader directly.

See also https://patchwork.kernel.org/patch/9561201/

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 13:19:10 -04:00
Alexander Boettcher
20f2a065e0 mbi: Use per segment a separate relocator chunk
Instead of setting up a all comprising relocator chunk for all segments,
use per segment a separate relocator chunk.

Currently, if the ELF is non-relocatable, a single relocator chunk will
comprise memory (between the segments) which gets overridden by the relst()
invocation of the movers code in grub_relocator16/32/64_boot().

The overridden memory may contain reserved ranges like VGA memory or ACPI
tables, which may lead to crashes or at least to strange boot behaviour.

Signed-off-by: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 13:19:10 -04:00
C. Masloch
b59db4f484 chainloader: patch in BPB's sectors_per_track and num_heads
These fields must reflect the ROM-BIOS's geometry for CHS-based
loaders to correctly load their next stage. Most loaders do not
query the ROM-BIOS (Int13.08), relying on the BPB fields to hold
the correct values already.

Tested with lDebug booted in qemu via grub2's
FreeDOS direct loading support, refer to
https://bitbucket.org/ecm/ldosboot + https://bitbucket.org/ecm/ldebug
(For this test, lDebug's iniload.asm must be assembled with
-D_QUERY_GEOMETRY=0 to leave the BPB values provided by grub.)

Signed-off-by: C. Masloch <pushbx@38.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Leif Lindholm
4b17e63148 arm: switch linux loader to linux_arm_kernel_header struct
Use kernel header struct and magic definition to align (and coexist) with
i386/arm64 ports.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Leif Lindholm
d8472e190c arm64: align linux kernel magic macro naming with i386
Change GRUB_ARM64_LINUX_MAGIC to GRUB_LINUX_ARM64_MAGIC_SIGNATURE.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Leif Lindholm
324bbebdb7 arm64: align linux kernel header struct naming with i386
Rename struct grub_arm64_linux_kernel_header -> linux_arm64_kernel_header.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Leif Lindholm
103779a19e i386: make struct linux_kernel_header architecture specific
struct linux_kernel_header -> struct linux_i386_kernel_header

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Leif Lindholm
1901a159bd make GRUB_LINUX_MAGIC_SIGNATURE architecture-specific
Rename GRUB_LINUX_MAGIC_SIGNATURE GRUB_LINUX_I386_MAGIC_SIGNATURE,
to be usable in code that supports more than one image type.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Leif Lindholm
e5ae7a2704 arm64/efi: move EFI_PAGE definitions to efi/memory.h
The EFI page definitions and macros are generic and should not be confined
to arm64 headers - so move to efi/memory.h.
Also add EFI_PAGE_SIZE macro.

Update loader sources to reflect new header location.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Daniel Kiper
5826e32c37 chainloader: Fix wrong break condition (must be AND not, OR)
The definition of bpb's num_total_sectors_16 and num_total_sectors_32
is that either the 16-bit field is non-zero and is used (in which case
eg mkfs.fat sets the 32-bit field to zero), or it is zero and the
32-bit field is used. Therefore, a BPB is invalid only if *both*
fields are zero; having one field as zero and the other as non-zero is
the case to be expected. (Indeed, according to Microsoft's specification
one of the fields *must* be zero, and the other non-zero.)

This affects all users of grub_chainloader_patch_bpb which are in
chainloader.c, freedos.c, and ntldr.c

Some descriptions of the semantics of these two fields:

https://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html

  The old 2-byte fields "total number of sectors" and "number of
  sectors per FAT" are now zero; this information is now found in
  the new 4-byte fields.

(Here given in the FAT32 EBPB section but the total sectors 16/32 bit
fields semantic is true of FAT12 and FAT16 too.)

https://wiki.osdev.org/FAT#BPB_.28BIOS_Parameter_Block.29

  19 | 2 | The total sectors in the logical volume. If this value is 0,
  it means there are more than 65535 sectors in the volume, and the actual
  count is stored in "Large Sectors (bytes 32-35).

  32 | 4 | Large amount of sector on media. This field is set if there
  are more than 65535 sectors in the volume.

(Doesn't specify what the "large" field is set to when unused, but as
mentioned mkfs.fat sets it to zero then.)

https://technet.microsoft.com/en-us/library/cc976796.aspx

  0x13 | WORD | 0x0000 |
  Small Sectors . The number of sectors on the volume represented in 16
  bits (< 65,536). For volumes larger than 65,536 sectors, this field
  has a value of zero and the Large Sectors field is used instead.

  0x20 | DWORD | 0x01F03E00 |
  Large Sectors . If the value of the Small Sectors field is zero, this
  field contains the total number of sectors in the FAT16 volume. If the
  value of the Small Sectors field is not zero, the value of this field
  is zero.

https://staff.washington.edu/dittrich/misc/fatgen103.pdf page 10

  BPB_TotSec16 | 19 | 2 |
  This field is the old 16-bit total count of sectors on the volume.
  This count includes the count of all sectors in all four regions of the
  volume. This field can be 0; if it is 0, then BPB_TotSec32 must be
  non-zero. For FAT32 volumes, this field must be 0. For FAT12 and
  FAT16 volumes, this field contains the sector count, and
  BPB_TotSec32 is 0 if the total sector count “fits” (is less than
  0x10000).

  BPB_TotSec32 | 32 | 4 |
  This field is the new 32-bit total count of sectors on the volume.
  This count includes the count of all sectors in all four regions of the
  volume. This field can be 0; if it is 0, then BPB_TotSec16 must be
  non-zero. For FAT32 volumes, this field must be non-zero. For
  FAT12/FAT16 volumes, this field contains the sector count if
  BPB_TotSec16 is 0 (count is greater than or equal to 0x10000).

(This specifies that an unused BPB_TotSec32 field is set to zero.)

By the way fix offsets in include/grub/fat.h.

Tested with lDebug booted in qemu via grub2's
FreeDOS direct loading support, refer to
https://bitbucket.org/ecm/ldosboot + https://bitbucket.org/ecm/ldebug

Signed-off-by: C. Masloch <pushbx@38.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Julien Grall
43d7414af7 arm64/xen: Add missing #address-cells and #size-cells properties
The properties #address-cells and #size-cells are used to know the
number of cells for ranges provided by "regs". If they don't exist, the
value are resp. 2 and 1.

Currently, when multiboot nodes are created it is assumed that #address-cells
and #size-cells are exactly 2. However, they are never set by GRUB and
will result to later failure when the device-tree is generated by GRUB
or contain different values.

To prevent this failure, create the both properties in the chosen nodes.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 12:16:25 -04:00
Vladimir Serbinenko
46159d35d3 Fix compilation for x86_64-efi. 2020-09-21 12:02:37 -04:00
Vladimir Serbinenko
f6c8225f8c multiboot fixup 2020-09-21 12:02:37 -04:00
Vladimir Serbinenko
ec4630c2b5 multiboot: disentangle multiboot and multiboot2.
Previously we had multiboot and multiboot2 declaring the same symbols.
This can potentially lead to aliasing and strange behaviours when e.g.
module instead of module2 is used with multiboot2.

Bug: #51137
2020-09-21 12:02:37 -04:00
Leif Lindholm
01f3dcc70a arm64 linux loader: improve type portability
In preparation for turning this into a common loader for 32-bit and 64-bit
platforms, ensure the code will compile cleanly for either.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
2020-09-21 12:02:37 -04:00
Leif Lindholm
793b90c851 efi: Add GRUB_PE32_MAGIC definition
Add a generic GRUB_PE32_MAGIC definition for the PE 'MZ' tag and delete
the existing one in arm64/linux.h.

Update arm64 Linux loader to use this new definition.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
2020-09-21 12:02:37 -04:00
Leif Lindholm
30f13fbfa6 efi: move fdt helper library
There is nothing ARM64 (or even ARM) specific about the efi fdt helper
library, which is used for locating or overriding a firmware-provided
devicetree in a UEFI system - so move it to loader/efi for reuse.

Move the fdtload.h include file to grub/efi and update path to
efi/fdtload.h in source code referring to it.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
2020-09-21 12:02:37 -04:00
Vladimir Serbinenko
6825a1d3f1 Remove grub_efi_allocate_pages.
grub_efi_allocate_pages Essentially does 2 unrelated things:
* Allocate at fixed address.
* Allocate at any address.

To switch between 2 different functions it uses address == 0 as magic
value which is wrong as 0 is a perfectly valid fixed adress to allocate at.
2020-09-21 12:02:37 -04:00
Vladimir Serbinenko
0c4852ea0e arm-efi: Fix compilation 2020-09-21 11:32:45 -04:00
Fu Wei
3418e2bd52 arm64: Add "--nounzip" option support in xen_module command
This patch adds "--nounzip" option support in order to
be compatible with the module command of multiboot on other architecture,
by this way we can simplify grub-mkconfig support code.

This patch also allow us to use zip compressed module(like Linux kernel
for Dom0).

Signed-off-by: Fu Wei <fu.wei@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 11:32:45 -04:00
Julien Grall
bf4d71848f arm64/xen_boot: Fix Xen boot using GRUB2 on AARCH64
Xen is currently crashing because of malformed compatible property for
the boot module. This is because the property string is not
null-terminated as requested by the ePAR spec.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Tested-by: Fu Wei <fu.wei@linaro.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-21 11:32:45 -04:00
Vladimir Serbinenko
5e1a343a37 arm_coreboot: Support loading linux images. 2020-09-21 11:32:45 -04:00
Vladimir Serbinenko
aa7585d04b arm-coreboot: Start new port. 2020-09-21 11:32:45 -04:00
Luca Bruno
750c71975e loader/i386: fix out of bound memory copy on non-UEFI linux
Ref: https://bugzilla.opensuse.org/show_bug.cgi?id=1029187
Ref: https://build.opensuse.org/package/rdiff/openSUSE:Factory/grub2?linkrev=base&rev=159
2019-10-24 16:59:37 +02:00
David Michael
f89e1cf69a Merge branch 'gnu' into sync 2017-04-27 12:05:22 -07:00
Vladimir Serbinenko
d454509bb8 Fix remaining cases of gcc 7 fallthrough warning.
They are all intended, so just add the relevant comment.
2017-04-12 01:42:38 +00:00
Andrei Borzenkov
4bd4a88725 i386, x86_64, ppc: fix switch fallthrough cases with GCC7
In util/getroot and efidisk slightly modify exitsing comment to mostly
retain it but still make GCC7 compliant with respect to fall through
annotation.

In grub-core/lib/xzembed/xz_dec_lzma2.c it adds same comments as
upstream.

In grub-core/tests/setjmp_tets.c declare functions as "noreturn" to
suppress GCC7 warning.

In grub-core/gnulib/regexec.c use new __attribute__, because existing
annotation is not recognized by GCC7 parser (which requires that comment
immediately precedes case statement).

Otherwise add FALLTHROUGH comment.

Closes: 50598
2017-04-04 19:23:55 +03:00
Vladimir Serbinenko
529818738f xen: Fix parsing of XZ kernel.
In case of xz, the uncompressed size is appended to xz data which confuses
our xz decompressor. Trim it.
2017-02-07 13:25:38 +01:00
Vladimir Serbinenko
8a96fc4093 xen: Fix handling of GRUB chainloading.
In case of GRUB we put remapper after domain pages and not at 0x0.
In this case we use max_addr to put remapper. Unfortunately we increment
max_addr as well in this case resulting in virt mapping mapping page
at old max_addr and trying to boot using new max_addr.

Closes 46014.
2017-02-07 00:42:43 +01:00
Geoff Levand
dc2eaa5855 loader: Add arm64 verity
Signed-off-by: Geoff Levand <geoff@infradead.org>
2017-01-25 14:54:46 -08:00
Geoff Levand
57fca7d1a3 loader: Move verity-hash.h to include
Signed-off-by: Geoff Levand <geoff@infradead.org>
2017-01-25 14:54:46 -08:00
David Michael
e576eb0cbc Merge remote-tracking branch 'upstream/master' 2017-01-23 14:02:45 -08:00
Andrei Borzenkov
972765fe82 linux: fix "vga=XX deprecated" warning for text mode
Arguments were in reverse order which resulted in

text is deprecated. Use set gfxpayload=vga=0 before linux command instead.
2017-01-08 15:52:49 +03:00
Andrei Borzenkov
ce95549cc5 efi: properly terminate filepath with NULL in chainloader
EFI File Path Media Device Path is defined as NULL terminated string;
but chainloader built file paths without final NULL. This caused error
with Secure Boot and Linux Foundation PreLoader on Acer with InsydeH20 BIOS.
Apparently firmware failed verification with EFI_INVALID_PARAMETER which is
considered fatal error by PreLoader.

Reported and tested by Giovanni Santini <itachi.sama.amaterasu@gmail.com>
2016-12-15 16:07:00 +03:00
Alexander Graf
fbca374105 arm64: Move firmware fdt search into global function
Searching for a device tree that EFI passes to us via configuration tables
is nothing architecture specific. Move it into generic code.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-11-10 13:20:56 +01:00
Juergen Gross
0de3eeb623 xen: add capability to load p2m list outside of kernel mapping
Modern pvops linux kernels support a p2m list not covered by the
kernel mapping. This capability is flagged by an elf-note specifying
the virtual address the kernel is expecting the p2m list to be mapped
to.

In case the elf-note is set by the kernel don't place the p2m list
into the kernel mapping, but map it to the given address. This will
allow to support domains with larger memory, as the kernel mapping is
limited to 2GB and a domain with huge memory in the TB range will have
a p2m list larger than this.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:22:06 +02:00
Juergen Gross
b67a95ecad xen: modify page table construction
Modify the page table construction to allow multiple virtual regions
to be mapped. This is done as preparation for removing the p2m list
from the initial kernel mapping in order to support huge pv domains.

This allows a cleaner approach for mapping the relocator page by
using this capability.

The interface to the assembler level of the relocator has to be changed
in order to be able to process multiple page table areas.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:22:06 +02:00
Juergen Gross
5500cefccd xen: add capability to load initrd outside of initial mapping
Modern pvops linux kernels support an initrd not covered by the initial
mapping. This capability is flagged by an elf-note.

In case the elf-note is set by the kernel don't place the initrd into
the initial mapping. This will allow to load larger initrds and/or
support domains with larger memory, as the initial mapping is limited
to 2GB and it is containing the p2m list.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:22:06 +02:00
Juergen Gross
d73976fdff xen: factor out allocation of page tables into separate function
Do the allocation of page tables in a separate function. This will
allow to do the allocation at different times of the boot preparations
depending on the features the kernel is supporting.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:22:06 +02:00
Juergen Gross
1fbb2b4b39 xen: factor out allocation of special pages into separate function
Do the allocation of special pages (start info, console and xenbus
ring buffers) in a separate function. This will allow to do the
allocation at different times of the boot preparations depending on
the features the kernel is supporting.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:22:06 +02:00
Juergen Gross
c221ea06b5 xen: factor out p2m list allocation into separate function
Do the p2m list allocation of the to be loaded kernel in a separate
function. This will allow doing the p2m list allocation at different
times of the boot preparations depending on the features the kernel
is supporting.

While at this remove superfluous setting of first_p2m_pfn and
nr_p2m_frames as those are needed only in case of the p2m list not
being mapped by the initial kernel mapping.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:22:06 +02:00
Juergen Gross
7e5fcb0b34 xen: add elfnote.h to avoid using numbers instead of constants
Various features and parameters of a pv-kernel are specified via
elf notes in the kernel image. Those notes are part of the interface
between the Xen hypervisor and the kernel.

Instead of using num,bers in the code when interpreting the elf notes
make use of the header supplied by Xen for that purpose.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:21:25 +02:00
Juergen Gross
6ae55ce103 xen: reduce number of global variables in xen loader
The loader for xen paravirtualized environment is using lots of global
variables. Reduce the number by making them either local or by putting
them into a single state structure.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:17:15 +02:00
Juergen Gross
c69d1858f1 xen: avoid memleaks on error
When loading a Xen pv-kernel avoid memory leaks in case of errors.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:17:15 +02:00
Juergen Gross
4231927e44 xen: make xen loader callable multiple times
The loader for xen paravirtualized environment isn't callable multiple
times as it won't free any memory in case of failure.

Call grub_relocator_unload() as other modules do it before allocating
a new relocator or when unloading the module.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2016-10-27 16:16:54 +02:00
Daniel Kiper
a620876e3b multiboot2: Add support for relocatable images
Currently multiboot2 protocol loads image exactly at address specified in
ELF or multiboot2 header. This solution works quite well on legacy BIOS
platforms. It is possible because memory regions are placed at predictable
addresses (though I was not able to find any spec which says that it is
strong requirement, so, it looks that it is just a goodwill of hardware
designers). However, EFI platforms are more volatile. Even if required
memory regions live at specific addresses then they are sometimes simply
not free (e.g. used by boot/runtime services on Dell PowerEdge R820 and
OVMF). This means that you are not able to just set up final image
destination on build time. You have to provide method to relocate image
contents to real load address which is usually different than load address
specified in ELF and multiboot2 headers.

This patch provides all needed machinery to do self relocation in image code.
First of all GRUB2 reads min_addr (min. load addr), max_addr (max. load addr),
align (required image alignment), preference (it says which memory regions are
preferred by image, e.g. none, low, high) from multiboot_header_tag_relocatable
header tag contained in binary (at this stage load addresses from multiboot2
and/or ELF headers are ignored). Later loader tries to fulfill request (not only
that one) and if it succeeds then it informs image about real load address via
multiboot_tag_load_base_addr tag. At this stage GRUB2 role is finished. Starting
from now executable must cope with relocations itself using whole static and
dynamic knowledge provided by boot loader.

This patch does not provide functionality which could do relocations using
ELF relocation data. However, I was asked by Konrad Rzeszutek Wilk and Vladimir
'phcoder' Serbinenko to investigate that thing. It looks that relevant machinery
could be added to existing code (including this patch) without huge effort.
Additionally, ELF relocation could live in parallel with self relocation provided
by this patch. However, during research I realized that first of all we should
establish the details how ELF relocatable image should look like and how it should
be build. At least to build proper test/example files.

So, this patch just provides support for self relocatable images. If ELF file
with relocs is loaded then GRUB2 complains loudly and ignores it. Support for
such files will be added later.

This patch was tested with Xen image which uses that functionality. However, this Xen
feature is still under development and new patchset will be released in about 2-3 weeks.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
2016-10-27 15:55:16 +02:00