mirror of
https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git
synced 2026-10-31 12:10:52 -04:00
Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 EFI changes from Ingo Molnar:
"Main changes:
- Add support for earlyprintk=efi which uses the EFI framebuffer.
Very useful for debugging boot problems.
- EFI stub support for large memory maps (more than 128 entries)
- EFI ARM support - this was mostly done by generalizing x86 <-> ARM
platform differences, such as by moving x86 EFI code into
drivers/firmware/efi/ and sharing it with ARM.
- Documentation updates
- misc fixes"
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
x86/efi: Add EFI framebuffer earlyprintk support
boot, efi: Remove redundant memset()
x86/efi: Fix config_table_type array termination
x86 efi: bugfix interrupt disabling sequence
x86: EFI stub support for large memory maps
efi: resolve warnings found on ARM compile
efi: Fix types in EFI calls to match EFI function definitions.
efi: Renames in handle_cmdline_files() to complete generalization.
efi: Generalize handle_ramdisks() and rename to handle_cmdline_files().
efi: Allow efi_free() to be called with size of 0
efi: use efi_get_memory_map() to get final map for x86
efi: generalize efi_get_memory_map()
efi: Rename __get_map() to efi_get_memory_map()
efi: Move unicode to ASCII conversion to shared function.
efi: Generalize relocate_kernel() for use by other architectures.
efi: Move relocate_kernel() to shared file.
efi: Enforce minimum alignment of 1 page on allocations.
efi: Rename memory allocation/free functions
efi: Add system table pointer argument to shared functions.
efi: Move common EFI stub code from x86 arch code to common location
...
This commit is contained in:
commit
69019d77c7
17 changed files with 1245 additions and 791 deletions
|
|
@ -1,65 +0,0 @@
|
|||
The EFI Boot Stub
|
||||
---------------------------
|
||||
|
||||
On the x86 platform, a bzImage can masquerade as a PE/COFF image,
|
||||
thereby convincing EFI firmware loaders to load it as an EFI
|
||||
executable. The code that modifies the bzImage header, along with the
|
||||
EFI-specific entry point that the firmware loader jumps to are
|
||||
collectively known as the "EFI boot stub", and live in
|
||||
arch/x86/boot/header.S and arch/x86/boot/compressed/eboot.c,
|
||||
respectively.
|
||||
|
||||
By using the EFI boot stub it's possible to boot a Linux kernel
|
||||
without the use of a conventional EFI boot loader, such as grub or
|
||||
elilo. Since the EFI boot stub performs the jobs of a boot loader, in
|
||||
a certain sense it *IS* the boot loader.
|
||||
|
||||
The EFI boot stub is enabled with the CONFIG_EFI_STUB kernel option.
|
||||
|
||||
|
||||
**** How to install bzImage.efi
|
||||
|
||||
The bzImage located in arch/x86/boot/bzImage must be copied to the EFI
|
||||
System Partiion (ESP) and renamed with the extension ".efi". Without
|
||||
the extension the EFI firmware loader will refuse to execute it. It's
|
||||
not possible to execute bzImage.efi from the usual Linux file systems
|
||||
because EFI firmware doesn't have support for them.
|
||||
|
||||
|
||||
**** Passing kernel parameters from the EFI shell
|
||||
|
||||
Arguments to the kernel can be passed after bzImage.efi, e.g.
|
||||
|
||||
fs0:> bzImage.efi console=ttyS0 root=/dev/sda4
|
||||
|
||||
|
||||
**** The "initrd=" option
|
||||
|
||||
Like most boot loaders, the EFI stub allows the user to specify
|
||||
multiple initrd files using the "initrd=" option. This is the only EFI
|
||||
stub-specific command line parameter, everything else is passed to the
|
||||
kernel when it boots.
|
||||
|
||||
The path to the initrd file must be an absolute path from the
|
||||
beginning of the ESP, relative path names do not work. Also, the path
|
||||
is an EFI-style path and directory elements must be separated with
|
||||
backslashes (\). For example, given the following directory layout,
|
||||
|
||||
fs0:>
|
||||
Kernels\
|
||||
bzImage.efi
|
||||
initrd-large.img
|
||||
|
||||
Ramdisks\
|
||||
initrd-small.img
|
||||
initrd-medium.img
|
||||
|
||||
to boot with the initrd-large.img file if the current working
|
||||
directory is fs0:\Kernels, the following command must be used,
|
||||
|
||||
fs0:\Kernels> bzImage.efi initrd=\Kernels\initrd-large.img
|
||||
|
||||
Notice how bzImage.efi can be specified with a relative path. That's
|
||||
because the image we're executing is interpreted by the EFI shell,
|
||||
which understands relative paths, whereas the rest of the command line
|
||||
is passed to bzImage.efi.
|
||||
Loading…
Reference in a new issue