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author | Aaron Durbin <adurbin@chromium.org> | 2013-02-08 17:28:04 -0600 |
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committer | Stefan Reinauer <stefan.reinauer@coreboot.org> | 2013-03-21 22:28:28 +0100 |
commit | 8e4a355773cc64a89b3fc4d79981cfb02bda7e66 (patch) | |
tree | 01a9e6d5fc66568fd5c318e5edf17d47e73f65e8 /src/arch/x86/boot/boot.c | |
parent | 43e4a80a92bf00540e4d9b0734eb53f32044226f (diff) | |
download | coreboot-8e4a355773cc64a89b3fc4d79981cfb02bda7e66.tar.xz |
coreboot: introduce CONFIG_RELOCATABLE_RAMSTAGE
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>
Diffstat (limited to 'src/arch/x86/boot/boot.c')
-rw-r--r-- | src/arch/x86/boot/boot.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/src/arch/x86/boot/boot.c b/src/arch/x86/boot/boot.c index d9cb02e776..4892c5e009 100644 --- a/src/arch/x86/boot/boot.c +++ b/src/arch/x86/boot/boot.c @@ -68,6 +68,34 @@ int elf_check_arch(Elf_ehdr *ehdr) } +#if CONFIG_RELOCATABLE_RAMSTAGE +/* When the ramstage is relocatable the elf loading ensures an elf image cannot + * be loaded over the ramstage code. */ +void jmp_to_elf_entry(void *entry, unsigned long unused1, unsigned long unused2) +{ + elf_boot_notes.hdr.b_checksum = + compute_ip_checksum(&elf_boot_notes, sizeof(elf_boot_notes)); + + /* Jump to kernel */ + __asm__ __volatile__( + " cld \n\t" + /* Now jump to the loaded image */ + " call *%0\n\t" + + /* The loaded image returned? */ + " cli \n\t" + " cld \n\t" + + :: + "r" (entry), +#if CONFIG_MULTIBOOT + "b"(mbi), "a" (MB_MAGIC2) +#else + "b"(&elf_boot_notes), "a" (0x0E1FB007) +#endif + ); +} +#else void jmp_to_elf_entry(void *entry, unsigned long buffer, unsigned long size) { extern unsigned char _ram_seg, _eram_seg; @@ -182,5 +210,6 @@ void jmp_to_elf_entry(void *entry, unsigned long buffer, unsigned long size) #endif ); } +#endif /* CONFIG_RELOCATABLE_RAMSTAGE */ |