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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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8
src/arch/x86/Makefile.inc
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@@ -157,6 +157,12 @@ $(objcbfs)/%.elf: $(objcbfs)/%.debug
################################################################################
# Build the coreboot_ram (stage 2)
ifeq ($(CONFIG_RELOCATABLE_RAMSTAGE),y)
$(eval $(call rmodule_link,$(objcbfs)/coreboot_ram.debug, $(obj)/arch/x86/boot/ramstage_module_header.ramstage.o $(objgenerated)/coreboot_ram.o, $(CONFIG_HEAP_SIZE)))
else
$(objcbfs)/coreboot_ram.debug: $(objgenerated)/coreboot_ram.o $(src)/arch/x86/coreboot_ram.ld
@printf " CC $(subst $(obj)/,,$(@))\n"
ifeq ($(CONFIG_COMPILER_LLVM_CLANG),y)
@@ -165,6 +171,8 @@ else
$(CC) -nostdlib -nostartfiles -static -o $@ -L$(obj) -T $(src)/arch/x86/coreboot_ram.ld $<
endif
endif
$(objgenerated)/coreboot_ram.o: $$(ramstage-objs) $(LIBGCC_FILE_NAME)
@printf " CC $(subst $(obj)/,,$(@))\n"
ifeq ($(CONFIG_COMPILER_LLVM_CLANG),y)