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ramstage: prepare for relocation

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The current ramstage code contains uses of symbols that cause issues
when the ramstage is relocatable. There are 2 scenarios resolved by this
patch:

1. Absolute symbols that are actually sizes/limits. The symbols are
   problematic when relocating a program because there is no way to
   distinguish a symbol that shouldn't be relocated and one that can.
   The only way to handle these symbols is to write a program to post
   process the relocations and keep a whitelist of ones that shouldn't
   be relocated. I don't believe that is a route that should be taken
   so fix the users of these sizes/limits encoded as absolute symbols
   to calculate the size at runtime or dereference a variable in memory
   containing the size/limit.

2. Absoulte symbols that were relocated to a fixed address. These
   absolute symbols are generated by assembly files to be placed at a
   fixed location. Again, these symbols are problematic because one
   can't distinguish a symbol that can't be relocated. The symbols
   are again resolved at runtime to allow for proper relocation.

For the symbols defining a size either use 2 symbols and calculate the
difference or provide a variable in memory containing the size.

Change-Id: I1ef2bfe6fd531308218bcaac5dcccabf8edf932c
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2789
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
This commit is contained in:
Aaron Durbin
2013-02-08 16:56:51 -06:00
committed by Stefan Reinauer
parent e8c866ad45
commit a146d58ca0
9 changed files with 76 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/cpu/intel/haswell/mp_init.c
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@@ -66,7 +66,7 @@ struct saved_msr {
extern char _binary_sipi_vector_start[];
/* These symbols are defined in c_start.S. */
extern char gdt[];
extern char gdt_limit[];
extern char gdt_end[];
extern char idtarg[];
/* This table keeps track of each CPU's APIC id. */
@@ -189,7 +189,7 @@ static void setup_default_sipi_vector_params(struct sipi_params *sp)
int i;
sp->gdt = (u32)&gdt;
sp->gdtlimit = (u32)&gdt_limit;
sp->gdtlimit = (u32)&gdt_end - (u32)&gdt - 1;
sp->idt_ptr = (u32)&idtarg;
sp->stack_size = CONFIG_STACK_SIZE;
sp->stack_top = (u32)&_estack;