[XS] Change in coreboot[main]: [DNM] cpu/x86/64bit/mode_switch2.S: Support runtime page tables

[Benjamin Doron (Code Review)]

Attention is currently required from: Jérémy Compostella.

Benjamin Doron has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/79863?usp=email )

Change subject: [DNM] cpu/x86/64bit/mode_switch2.S: Support runtime page tables
......................................................................

[DNM] cpu/x86/64bit/mode_switch2.S: Support runtime page tables

Try to get page table address from the `page_tables` variable in mmu.c.
Fallback to hardcoded page tables in ROM.

Untested.

Change-Id: Ic964038fd4dd810015e6a355a171e49db648c8fe
Signed-off-by: Benjamin Doron 
---
M src/cpu/x86/64bit/mode_switch2.S
1 file changed, 4 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/63/79863/1

diff --git a/src/cpu/x86/64bit/mode_switch2.S b/src/cpu/x86/64bit/mode_switch2.S
index cbd98a0..7376275 100644
--- a/src/cpu/x86/64bit/mode_switch2.S
+++ b/src/cpu/x86/64bit/mode_switch2.S
@@ -19,8 +19,12 @@
    mov	%esp, %ebp

/* Get page table address */
+	movl	page_tables, %eax
+	cmp	%eax, 0
+	jne	1f
    movl	$(CONFIG_ARCH_X86_64_PGTBL_LOC), %eax

+1:
    /* Enter long mode, preserves ebx */
    #include <cpu/x86/64bit/entry64.inc>