The Linux trampoline code does not set up the segment descriptors for
__BOOT_CS and __BOOT_DS as described in the Linux kernel
documentation:
... a GDT must be loaded with the descriptors for selectors
__BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G
flat segment; __BOOT_CS must have execute/read permission, and
__BOOT_DS must have read/write permission;
This is not a problem when launching a Linux payload from coreboot, as
coreboot configures the segment descriptors at selectors 0x10 and
0x18. Coreboot configures these selectors in the ramstage to match
what the Linux kernel expects (see
coreboot/src/arch/x86/lib/c_start.S).
When the cbfs payload is launched in other environments, SeaBIOS for
example, the segment descriptors are configured differently and the
cbfs Linux payload does not work.
If the cbfs Linux payload is to be used in multiple environments
should the trampoline needs to take care of the descriptors that Linux
requires.
This patch updates the Linux trampoline code to configure the 4G flat
descriptors that Linux expects. The configuration is borrowed from
the descriptor configs in coreboot/src/arch/x86/lib/c_start.S for
selectors 0x10 and 0x18.
The linux_trampoline code is slightly refractored by defining the
trampoline entry address, 0x40000, as TRAMPOLINE_ENTRY_LOC. This
definition is moved into a separate header file, linux_trampoline.h.
This header file is now included by both the trampoline assembly
language code and the trampoline loader C code.
The trampoline assembly language code can now use TRAMPOLINE_ENTRY_LOC
as scratch space for the sgdt CPU instruction.
Testing Done:
Verified the Linux payload is booted correctly in the following
environments:
1. Coreboot -> Linux Payload
2. Coreboot -> SeaBIOS -> Linux Payload: (previously did not work)
Change-Id: I888f74ff43073a6b7318f6713a8d4ecb804c0162
Signed-off-by: Curt Brune <curt@cumulusnetworks.com>
Reviewed-on: http://review.coreboot.org/6796
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
For bzImages the trampoline segment is added unconditionally.
However, that segment wasn't properly being accounted for.
Explicitly add the trampoline segments like the other ones.
Change-Id: I74f6fcc2a65615bb87578a8a3a76cecf858fe856
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5702
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
This change started with tracking down a bug where the trampoline
size was not being taken into account for sizing the output buffer
leading to a heap corruption. I was having a hard time keeping
track of what num_segments actually tracked as well as what parts
were being placed in the output buffer. Here's my attempt at
hopefully providing more clarity.
This change doesn't crash when adding a bzImage:
$ dd if=/dev/zero of=bb.bin bs=64 count=1
$ ./cbfstool tmp.rom create -s 4M -B bb.bin -m x86 -a 64
$ ./cbfstool tmp.rom add-payload -f ~/Downloads/bzImage -C "1" -n
"fallback"/payload
Change-Id: Ib1de1ddfec3c7102facffc5815c52b340fcdc628
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5408
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
When I changed mkpayload, I did not realize we had a duplicate
block of code in the linux payload code. Have it use the same
header generator as the standard payload code does.
Change-Id: Ie39540089ce89b704290c89127da4c7b051ecb0e
Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Reviewed-on: http://review.coreboot.org/5115
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
In the great tradition of LinuxBIOS this allows adding
a kernel as payload. add-payload is extended to also
allow adding an initial ramdisk (-I filename) and a
command line (-C console=ttyS0).
Change-Id: Iaca499a98b0adf0134e78d6bf020b6531a626aaa
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/3302
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Curt Brune