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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-11 20:48:30 -0500 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-11 20:48:30 -0500 |
| commit | 69019d77c71472428a5d67ab8bb7cfa9145000d0 (patch) | |
| tree | 370f038a801c5ceee5266bf95944a458bcc0bfbf /Documentation/x86 | |
| parent | 6df1e7f2e96721dfdbfd8a034e52bc81916f978c (diff) | |
| parent | 88392e9dd5a524b8194f1045369c7d0eb16d9f32 (diff) | |
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
...
Diffstat (limited to 'Documentation/x86')
| -rw-r--r-- | Documentation/x86/efi-stub.txt | 65 |
1 files changed, 0 insertions, 65 deletions
diff --git a/Documentation/x86/efi-stub.txt b/Documentation/x86/efi-stub.txt deleted file mode 100644 index 44e6bb6ead10..000000000000 --- a/Documentation/x86/efi-stub.txt +++ /dev/null | |||
| @@ -1,65 +0,0 @@ | |||
| 1 | The EFI Boot Stub | ||
| 2 | --------------------------- | ||
| 3 | |||
| 4 | On the x86 platform, a bzImage can masquerade as a PE/COFF image, | ||
| 5 | thereby convincing EFI firmware loaders to load it as an EFI | ||
| 6 | executable. The code that modifies the bzImage header, along with the | ||
| 7 | EFI-specific entry point that the firmware loader jumps to are | ||
| 8 | collectively known as the "EFI boot stub", and live in | ||
| 9 | arch/x86/boot/header.S and arch/x86/boot/compressed/eboot.c, | ||
| 10 | respectively. | ||
| 11 | |||
| 12 | By using the EFI boot stub it's possible to boot a Linux kernel | ||
| 13 | without the use of a conventional EFI boot loader, such as grub or | ||
| 14 | elilo. Since the EFI boot stub performs the jobs of a boot loader, in | ||
| 15 | a certain sense it *IS* the boot loader. | ||
| 16 | |||
| 17 | The EFI boot stub is enabled with the CONFIG_EFI_STUB kernel option. | ||
| 18 | |||
| 19 | |||
| 20 | **** How to install bzImage.efi | ||
| 21 | |||
| 22 | The bzImage located in arch/x86/boot/bzImage must be copied to the EFI | ||
| 23 | System Partiion (ESP) and renamed with the extension ".efi". Without | ||
| 24 | the extension the EFI firmware loader will refuse to execute it. It's | ||
| 25 | not possible to execute bzImage.efi from the usual Linux file systems | ||
| 26 | because EFI firmware doesn't have support for them. | ||
| 27 | |||
| 28 | |||
| 29 | **** Passing kernel parameters from the EFI shell | ||
| 30 | |||
| 31 | Arguments to the kernel can be passed after bzImage.efi, e.g. | ||
| 32 | |||
| 33 | fs0:> bzImage.efi console=ttyS0 root=/dev/sda4 | ||
| 34 | |||
| 35 | |||
| 36 | **** The "initrd=" option | ||
| 37 | |||
| 38 | Like most boot loaders, the EFI stub allows the user to specify | ||
| 39 | multiple initrd files using the "initrd=" option. This is the only EFI | ||
| 40 | stub-specific command line parameter, everything else is passed to the | ||
| 41 | kernel when it boots. | ||
| 42 | |||
| 43 | The path to the initrd file must be an absolute path from the | ||
| 44 | beginning of the ESP, relative path names do not work. Also, the path | ||
| 45 | is an EFI-style path and directory elements must be separated with | ||
| 46 | backslashes (\). For example, given the following directory layout, | ||
| 47 | |||
| 48 | fs0:> | ||
| 49 | Kernels\ | ||
| 50 | bzImage.efi | ||
| 51 | initrd-large.img | ||
| 52 | |||
| 53 | Ramdisks\ | ||
| 54 | initrd-small.img | ||
| 55 | initrd-medium.img | ||
| 56 | |||
| 57 | to boot with the initrd-large.img file if the current working | ||
| 58 | directory is fs0:\Kernels, the following command must be used, | ||
| 59 | |||
| 60 | fs0:\Kernels> bzImage.efi initrd=\Kernels\initrd-large.img | ||
| 61 | |||
| 62 | Notice how bzImage.efi can be specified with a relative path. That's | ||
| 63 | because the image we're executing is interpreted by the EFI shell, | ||
| 64 | which understands relative paths, whereas the rest of the command line | ||
| 65 | is passed to bzImage.efi. | ||
