From a146d58ca0375a12f23dc5a4bd25adfa3423114f Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Fri, 8 Feb 2013 16:56:51 -0600 Subject: ramstage: prepare for relocation 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 Reviewed-on: http://review.coreboot.org/2789 Tested-by: build bot (Jenkins) Reviewed-by: Marc Jones --- src/cpu/x86/lapic/lapic_cpu_init.c | 18 ++++++++++++++++++ src/cpu/x86/lapic/secondary.S | 8 +++++--- 2 files changed, 23 insertions(+), 3 deletions(-) (limited to 'src/cpu/x86') diff --git a/src/cpu/x86/lapic/lapic_cpu_init.c b/src/cpu/x86/lapic/lapic_cpu_init.c index 9a00b8289f..69430d551f 100644 --- a/src/cpu/x86/lapic/lapic_cpu_init.c +++ b/src/cpu/x86/lapic/lapic_cpu_init.c @@ -52,12 +52,30 @@ int lowmem_backup_size; #endif extern char _secondary_start[]; +extern char _secondary_gdt_addr[]; +extern char gdt[]; +extern char gdt_end[]; + +static inline void setup_secondary_gdt(void) +{ + u16 *gdt_limit; + u32 *gdt_base; + + gdt_limit = (void *)&_secondary_gdt_addr; + gdt_base = (void *)&gdt_limit[1]; + + *gdt_limit = (u32)&gdt_end - (u32)&gdt - 1; + *gdt_base = (u32)&gdt; +} static void copy_secondary_start_to_lowest_1M(void) { extern char _secondary_start_end[]; unsigned long code_size; + /* Fill in secondary_start's local gdt. */ + setup_secondary_gdt(); + code_size = (unsigned long)_secondary_start_end - (unsigned long)_secondary_start; #if CONFIG_HAVE_ACPI_RESUME diff --git a/src/cpu/x86/lapic/secondary.S b/src/cpu/x86/lapic/secondary.S index 2e0620e2da..6edcd0a366 100644 --- a/src/cpu/x86/lapic/secondary.S +++ b/src/cpu/x86/lapic/secondary.S @@ -3,7 +3,7 @@ #if CONFIG_SMP && CONFIG_MAX_CPUS > 1 .text - .globl _secondary_start, _secondary_start_end + .globl _secondary_start, _secondary_start_end, _secondary_gdt_addr .balign 4096 _secondary_start: .code16 @@ -28,9 +28,11 @@ _secondary_start: ljmpl $0x10, $__ap_protected_start + /* This will get filled in by C code. */ +_secondary_gdt_addr: gdtaddr: - .word gdt_limit /* the table limit */ - .long gdt /* we know the offset */ + .word 0 /* the table limit */ + .long 0 /* we know the offset */ _secondary_start_end: -- cgit v1.2.3