GNUBoot
/
coreboot-kgpe-d16
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
coreboot-kgpe-d16/Documentation/arch/x86/index.md

67 lines
2.3 KiB
Markdown
Raw Normal View History

Documentation: Add arch x86 Describe state and assuptions made about x86_64 support. Change-Id: I308a09b0eac269afd30df95ed3ea195238a6cfbe Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/30056 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2018-12-05 19:09:04 +01:00
# x86 architecture documentation
This section contains documentation about coreboot on x86 architecture.
cpu/x86/pae/pgtbl: Add memset with PAE To clear all DRAM on x86_32, add a new method that uses PAE to access more than 32bit of address space. Add Documentation as well. Required for clearing all system memory as part of security API. Tested on wedge100s: Takes less than 2 seconds to clear 8GiB of DRAM. Tested on P8H61M-Pro: Takes less than 1 second to clear 4GiB of DRAM. Change-Id: I00f7ecf87b5c9227a9d58a0b61eecc38007e1a57 Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/31549 Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2019-02-21 10:27:04 +01:00
* [x86 PAE support](pae.md)
Documentation: Add arch x86 Describe state and assuptions made about x86_64 support. Change-Id: I308a09b0eac269afd30df95ed3ea195238a6cfbe Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/30056 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2018-12-05 19:09:04 +01:00
## State of x86_64 support
At the moment there's no single board that supports x86_64 or to be exact
`ARCH_RAMSTAGE_X86_64` and `ARCH_ROMSTAGE_X86_64`.
In order to add support for x86_64 the following assumptions are made:
* The CPU supports long mode
* All memory returned by malloc must be below 4GiB in physical memory
* All code that is to be run must be below 4GiB in physical memory
* The high dword of pointers is always zero
* The reference implementation is qemu
* The CPU supports 1GiB hugepages
cpu/qemu-x86: Add x86_64 bootblock support Add support for x86_64 bootblock on qemu. Introduce a new approach to long mode support. The previous patch set generated page tables at runtime and placed them in heap. The new approach places the page tables in memory mapped ROM. Introduce a new tool called pgtblgen that creates x86 long mode compatible page tables and writes those to a file. The file is included into the CBFS and placed at a predefined offset. Add assembly code to load the page tables, based on a Kconfig symbol and enter long in bootblock. The code can be easily ported to real hardware bootblock. Tested on qemu q35. Change-Id: Iec92c6cea464c97c18a0811e2e91bc22133ace42 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/35680 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2019-09-28 17:44:01 +02:00
## Assuptions for all stages using the reference implementation
* 0-4GiB are identity mapped using 2MiB-pages as WB
Documentation: Add arch x86 Describe state and assuptions made about x86_64 support. Change-Id: I308a09b0eac269afd30df95ed3ea195238a6cfbe Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/30056 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2018-12-05 19:09:04 +01:00
* Memory above 4GiB isn't accessible
cpu/qemu-x86: Add x86_64 bootblock support Add support for x86_64 bootblock on qemu. Introduce a new approach to long mode support. The previous patch set generated page tables at runtime and placed them in heap. The new approach places the page tables in memory mapped ROM. Introduce a new tool called pgtblgen that creates x86 long mode compatible page tables and writes those to a file. The file is included into the CBFS and placed at a predefined offset. Add assembly code to load the page tables, based on a Kconfig symbol and enter long in bootblock. The code can be easily ported to real hardware bootblock. Tested on qemu q35. Change-Id: Iec92c6cea464c97c18a0811e2e91bc22133ace42 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/35680 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2019-09-28 17:44:01 +02:00
* page tables reside in memory mapped ROM
* A stage can install new page tables in RAM
Documentation: Add arch x86 Describe state and assuptions made about x86_64 support. Change-Id: I308a09b0eac269afd30df95ed3ea195238a6cfbe Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/30056 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2018-12-05 19:09:04 +01:00
cpu/qemu-x86: Add x86_64 bootblock support Add support for x86_64 bootblock on qemu. Introduce a new approach to long mode support. The previous patch set generated page tables at runtime and placed them in heap. The new approach places the page tables in memory mapped ROM. Introduce a new tool called pgtblgen that creates x86 long mode compatible page tables and writes those to a file. The file is included into the CBFS and placed at a predefined offset. Add assembly code to load the page tables, based on a Kconfig symbol and enter long in bootblock. The code can be easily ported to real hardware bootblock. Tested on qemu q35. Change-Id: Iec92c6cea464c97c18a0811e2e91bc22133ace42 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/35680 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2019-09-28 17:44:01 +02:00
## Page tables
Page tables are generated by a tool in `util/pgtblgen/pgtblgen`. It writes
the page tables to a file which is then included into the CBFS as file called
`pagetables`.
To generate the static page tables it must know the physical address where to
place the file.
The page tables contains the following structure:
* PML4E pointing to PDPE
* PDPE with *$n* entries each pointing to PDE
* *$n* PDEs with 512 entries each
At the moment *$n* is 4, which results in identity mapping the lower 4 GiB.
Documentation: Add arch x86 Describe state and assuptions made about x86_64 support. Change-Id: I308a09b0eac269afd30df95ed3ea195238a6cfbe Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/30056 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2018-12-05 19:09:04 +01:00
## Steps to add basic support for x86_64
* Add x86_64 toolchain support - *DONE*
* Fix compilation errors - *DONE*
* Fix linker errors - *TODO*
cpu/qemu-x86: Add x86_64 bootblock support Add support for x86_64 bootblock on qemu. Introduce a new approach to long mode support. The previous patch set generated page tables at runtime and placed them in heap. The new approach places the page tables in memory mapped ROM. Introduce a new tool called pgtblgen that creates x86 long mode compatible page tables and writes those to a file. The file is included into the CBFS and placed at a predefined offset. Add assembly code to load the page tables, based on a Kconfig symbol and enter long in bootblock. The code can be easily ported to real hardware bootblock. Tested on qemu q35. Change-Id: Iec92c6cea464c97c18a0811e2e91bc22133ace42 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/35680 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2019-09-28 17:44:01 +02:00
* Add x86_64 rmodule support - *DONE*
arch/x86: Support x86_64 exceptions * Doesn't affect existing x86_32 code. Tested on qemu using division by zero. Tested on Lenovo T410 with additional x86_64 patches. Change-Id: Idd12c90a95cc2989eb9b2a718740a84222193f48 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/30117 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Raul Rangel <rrangel@chromium.org>
2019-06-24 18:44:33 +02:00
* Add x86_64 exception handlers - *DONE*
cpu/qemu-x86: Add x86_64 bootblock support Add support for x86_64 bootblock on qemu. Introduce a new approach to long mode support. The previous patch set generated page tables at runtime and placed them in heap. The new approach places the page tables in memory mapped ROM. Introduce a new tool called pgtblgen that creates x86 long mode compatible page tables and writes those to a file. The file is included into the CBFS and placed at a predefined offset. Add assembly code to load the page tables, based on a Kconfig symbol and enter long in bootblock. The code can be easily ported to real hardware bootblock. Tested on qemu q35. Change-Id: Iec92c6cea464c97c18a0811e2e91bc22133ace42 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/35680 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2019-09-28 17:44:01 +02:00
* Setup page tables for long mode - *DONE*
* Add assembly code for long mode - *DONE*
cpu/x86/smm: Add support for long mode Enable long mode in SMM handler. x86_32 isn't affected by this change. As the rsm instruction used to leave SMM doesn't restore MSR registers, drop back to protected mode after running the smi_handler and restore IA32_EFER MSR (which enables long mode support) to previous value. NOTE: This commit does NOT introduce a new security model. It uses the same page tables as the remaining firmware does. This can be a security risk if someone is able to manipulate the page tables stored in ROM at runtime. USE FOR TESTING ONLY! Tested on Qemu Q35. Change-Id: I8bba4af4688c723fc079ae905dac95f57ea956f8 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/35681 Reviewed-by: Raul Rangel <rrangel@chromium.org> Reviewed-by: Angel Pons <th3fanbus@gmail.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2019-09-29 11:08:33 +02:00
* Add assembly code for SMM - *DONE*
cpu/qemu-x86: Add x86_64 bootblock support Add support for x86_64 bootblock on qemu. Introduce a new approach to long mode support. The previous patch set generated page tables at runtime and placed them in heap. The new approach places the page tables in memory mapped ROM. Introduce a new tool called pgtblgen that creates x86 long mode compatible page tables and writes those to a file. The file is included into the CBFS and placed at a predefined offset. Add assembly code to load the page tables, based on a Kconfig symbol and enter long in bootblock. The code can be easily ported to real hardware bootblock. Tested on qemu q35. Change-Id: Iec92c6cea464c97c18a0811e2e91bc22133ace42 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/35680 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2019-09-28 17:44:01 +02:00
* Add assembly code for postcar stage - *TODO*
Documentation: Add arch x86 Describe state and assuptions made about x86_64 support. Change-Id: I308a09b0eac269afd30df95ed3ea195238a6cfbe Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/30056 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2018-12-05 19:09:04 +01:00
* Add assembly code to return to protected mode - *TODO*
* Implement reference code for mainboard `emulation/qemu-q35` - *TODO*
Documentation: Add TODOs for secure SMM when using x86_64 Change-Id: I157238f18bc1c2eba0adc0b87caa9adaf3fc5d38 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/42982 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-by: Raul Rangel <rrangel@chromium.org>
2020-06-30 20:24:11 +02:00
## Future work
1. Fine grained page tables for SMM:
* Must not have execute and write permissions for the same page.
* Must allow only that TSEG pages can be marked executable
* Must reside in SMRAM
2. Support 64bit PCI BARs above 4GiB
3. Place and run code above 4GiB
Documentation: Add arch x86 Describe state and assuptions made about x86_64 support. Change-Id: I308a09b0eac269afd30df95ed3ea195238a6cfbe Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/30056 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2018-12-05 19:09:04 +01:00
## Porting other boards
* Fix compilation errors
* Test how well CAR works with x86_64 and paging
* Improve mode switches
* Test libgfxinit / VGA Option ROMs / FSP