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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
mb/emulation/qemu-q35,qemu-i440fx: Add x86_64 support * Enable optional x86_64 romstage, postcar and ramstage * Add Kconfig for x86_64 compilation * Add documentation for x86 qemu mainboards * Increase CAR stack as x86_64 uses more than 0x4000 bytes Working: * Boots to Linux * Boots to SeaBIOS * Drops to protected mode at end of ramstage * Enumerates PCI devices * Relocateable ramstage * SMM Change-Id: If2f02a95b2f91ab51043d4e81054354f4a6eb5d5 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/29667 Reviewed-by: Arthur Heymans <arthur@aheymans.xyz> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2018-11-15 13:42:15 +01:00
At the moment there's only experimental x86_64 support.
The `emulation/qemu-i440fx` and `emulation/qemu-q35` boards do support
*ARCH_RAMSTAGE_X86_64* , *ARCH_POSTCAR_X86_64* and *ARCH_ROMSTAGE_X86_64*.
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
mb/emulation/qemu-q35,qemu-i440fx: Add x86_64 support * Enable optional x86_64 romstage, postcar and ramstage * Add Kconfig for x86_64 compilation * Add documentation for x86 qemu mainboards * Increase CAR stack as x86_64 uses more than 0x4000 bytes Working: * Boots to Linux * Boots to SeaBIOS * Drops to protected mode at end of ramstage * Enumerates PCI devices * Relocateable ramstage * SMM Change-Id: If2f02a95b2f91ab51043d4e81054354f4a6eb5d5 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/29667 Reviewed-by: Arthur Heymans <arthur@aheymans.xyz> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2018-11-15 13:42:15 +01:00
In order to add support for x86_64 the following assumptions were made:
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
* 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
arch/x86/boot: Jump to payload in protected mode * On ARCH_RAMSTAGE_X86_64 jump to the payload in protected mode. * Add a helper function to jump to arbitrary code in protected mode, similar to the real mode call handler. * Doesn't affect existing x86_32 code. * Add a macro to cast pointer to uint32_t that dies if it would overflow on conversion Tested on QEMU Q35 using SeaBIOS as payload. Tested on Lenovo T410 with additional x86_64 patches. Change-Id: I6552ac30f1b6205e08e16d251328e01ce3fbfd14 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/30118 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
2018-12-09 10:48:59 +01:00
* x86 payloads are loaded below 4GiB in physical memory and are jumped
to in *protected mode*
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
Documentation: Fix spelling of *assumptions* Change-Id: I36e0e713647cfc0d25e6b4ead81aa212be530afb Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de> Reviewed-on: https://review.coreboot.org/c/coreboot/+/33742 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2019-06-24 18:39:43 +02:00
## Assumptions for all stages using the reference implementation
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
* 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
mb/emulation/qemu-q35,qemu-i440fx: Add x86_64 support * Enable optional x86_64 romstage, postcar and ramstage * Add Kconfig for x86_64 compilation * Add documentation for x86 qemu mainboards * Increase CAR stack as x86_64 uses more than 0x4000 bytes Working: * Boots to Linux * Boots to SeaBIOS * Drops to protected mode at end of ramstage * Enumerates PCI devices * Relocateable ramstage * SMM Change-Id: If2f02a95b2f91ab51043d4e81054354f4a6eb5d5 Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/29667 Reviewed-by: Arthur Heymans <arthur@aheymans.xyz> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2018-11-15 13:42:15 +01:00
## Basic x86_64 support
Basic support for x86_64 has been implemented for QEMU mainboard target.
## Reference implementation
The reference implementation is
* [QEMU i440fx](../../mainboard/emulation/qemu-i440fx.md)
* [QEMU Q35](../../mainboard/emulation/qemu-q35.md)
## TODO
* Identity map memory above 4GiB in ramstage
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
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
Documentation: Add known bugs of x86_64 code on real hardware The bugs happen on real hardware or in qemu with KVM enabled. The very same code runs on some real devices and it runs in qemu with KVM disabled. The bugs are so strange that no root cause could be found yet. Change-Id: I01050f2e38f92c6b96e3258a5b619aa9ee685acc Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/44733 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Angel Pons <th3fanbus@gmail.com>
2020-08-24 08:19:45 +02:00
## Known bugs on real hardware
According to Intel x86_64 mode hasn't been validated in CAR environments.
Until now it could be verified on various Intel platforms and no issues have
been found.
## Known bugs on KVM enabled qemu
The `x86_64` reference code runs fine in qemu soft-cpu, but has serious issues
when using KVM mode on some machines. The workaround is to *not* place
page-tables in ROM, as done in
[CB:49228](https://review.coreboot.org/c/coreboot/+/49228).
Here's a list of known issues:
* After entering long mode, the FPU doesn't work anymore, including accessing
MMX registers. It works fine before entering long mode. It works fine when
switching back to protected mode. Other registers, like SSE registers, are
working fine.
* Reading from virtual memory, when the page tables are stored in ROM, causes
the MMU to abort the "page table walking" mechanism when the lower address
bits of the virtual address to be translated have a specific pattern.
Instead of loading the correct physical page, the one containing the
page tables in ROM will be loaded and used, which breaks code and data as
the page table doesn't contain the expected data. This in turn leads to
undefined behaviour whenever the 'wrong' address is being read.
* Disabling paging in compability mode crashes the CPU.
* Returning from long mode to compability mode crashes the CPU.
* Entering long mode crashes on AMD host platforms.