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coreboot: introduce CONFIG_RELOCATABLE_RAMSTAGE

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This patch adds an option to build the ramstage as a reloctable binary.
It uses the rmodule library for the relocation. The main changes
consist of the following:

1. The ramstage is loaded just under the cmbem space.
2. Payloads cannot be loaded over where ramstage is loaded. If a payload
   is attempted to load where the relocatable ramstage resides the load
   is aborted.
3. The memory occupied by the ramstage is reserved from the OS's usage
   using the romstage_handoff structure stored in cbmem. This region is
   communicated to ramstage by an CBMEM_ID_ROMSTAGE_INFO entry in cbmem.
4. There is no need to reserve cbmem space for the OS controlled memory for
   the resume path because the ramsage region has been reserved in #3.
5. Since no memory needs to be preserved in the wake path, the loading
   and begin of execution of a elf payload is straight forward.

Change-Id: Ia66cf1be65c29fa25ca7bd9ea6c8f11d7eee05f5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2792
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
This commit is contained in:
Aaron Durbin
2013-02-08 17:28:04 -06:00
committed by Stefan Reinauer
parent 43e4a80a92
commit 8e4a355773
11 changed files with 170 additions and 0 deletions
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18
src/Kconfig
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@@ -307,7 +307,14 @@ config HAVE_INIT_TIMER
config HIGH_SCRATCH_MEMORY_SIZE
hex
default 0x5000 if RELOCATABLE_RAMSTAGE
default 0x0
help
The amount of extra memory to reserve from the OS. If
RELOCATABLE_RAMSTAGE is enabled a size of 20KiB is reserved. This is
for the use of a stack in romstage after memory has been initialized.
The stack size required in romstage can be large when needing to
decompress the ramstage.
config USE_OPTION_TABLE
bool
@@ -374,6 +381,17 @@ config RELOCATABLE_MODULES
building relocatable modules in the ram stage. Those modules can be
loaded anywhere and all the relocations are handled automatically.
config RELOCATABLE_RAMSTAGE
depends on RELOCATABLE_MODULES
bool "Build the ramstage to be relocatable in 32-bit address space."
default n
help
The reloctable ramstage support allows for the ramstage to be built
as a relocatable module. The stage loader can identify a place
out of the OS way so that copying memory is unnecessary during an S3
wake. When selecting this option the romstage is responsible for
determing a stack location to use for loading the ramstage.
config HAVE_ACPI_TABLES
bool
help