[S] Change in coreboot[main]: cpu/x86: Make 1GB paging the default

[Julius Werner (Code Review)]

Julius Werner has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/82792?usp=email )

Change subject: cpu/x86: Make 1GB paging the default
......................................................................

cpu/x86: Make 1GB paging the default

This patch flips the polarity of CONFIG_USE_1G_PAGES_TLB into
CONFIG_NEED_SMALL_2MB_PAGE_TABLES which is off by default, meaining
most boards will build the smaller 1GB pages. Only CPUs that actually
don't support that feature should manually select the option to build
2MB pages, which to my knowledge(?) is only QEMU.

Change-Id: I2cf1237a7fb63b8904c2a3d57fead162c66bacde
Signed-off-by: Julius Werner 
---
M src/cpu/qemu-x86/Kconfig
M src/cpu/x86/64bit/Makefile.mk
M src/cpu/x86/Kconfig
3 files changed, 9 insertions(+), 6 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/92/82792/1

diff --git a/src/cpu/qemu-x86/Kconfig b/src/cpu/qemu-x86/Kconfig
index b5ff6f0..221a7ba 100644
--- a/src/cpu/qemu-x86/Kconfig
+++ b/src/cpu/qemu-x86/Kconfig
@@ -7,6 +7,7 @@
    select UDELAY_TSC
    select TSC_MONOTONIC_TIMER
    select UNKNOWN_TSC_RATE
+	select NEED_SMALL_2MB_PAGE_TABLES	# QEMU doesn't support 1GB pages

if CPU_QEMU_X86

diff --git a/src/cpu/x86/64bit/Makefile.mk b/src/cpu/x86/64bit/Makefile.mk
index b24e4d7..1fda087 100644
--- a/src/cpu/x86/64bit/Makefile.mk
+++ b/src/cpu/x86/64bit/Makefile.mk
@@ -3,10 +3,10 @@
 all_x86-y += mode_switch.S
 all_x86-y += mode_switch2.S

-ifeq ($(CONFIG_USE_1G_PAGES_TLB),y)
-PAGETABLE_SRC := pt1G.S
-else
+ifeq ($(CONFIG_NEED_SMALL_2MB_PAGE_TABLES),y)
 PAGETABLE_SRC := pt.S
+else
+PAGETABLE_SRC := pt1G.S
 endif

all_x86-y += $(PAGETABLE_SRC)
diff --git a/src/cpu/x86/Kconfig b/src/cpu/x86/Kconfig
index ec1fa13..83a5e16 100644
--- a/src/cpu/x86/Kconfig
+++ b/src/cpu/x86/Kconfig
@@ -152,12 +152,14 @@
    bool
    default n

-config USE_1G_PAGES_TLB
+config NEED_SMALL_2MB_PAGE_TABLES
    bool
    default n
    help
-	  Select this option to enable access to up to 512 GiB of memory
-	  by using 1 GiB large pages.
+	  Select this option from boards/SoCs that do not support the Page1GB
+	  CPUID feature (CPUID.80000001H:EDX.bit26). This started being
+	  available in all CPUs around 2010ish, so nowadays this option is
+	  mostly just needed for emulation targets.

config SMM_ASEG
    bool