7 files changed, 88 insertions, 7 deletions
diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc
index 56b176d6b6..9b3101dc77 100644
--- a/src/arch/x86/Makefile.inc
+++ b/src/arch/x86/Makefile.inc
@@ -145,6 +145,9 @@ $(1)-y += memlayout.ld
 $(1)-y += assembly_entry.S
 $$(obj)/arch/x86/assembly_entry.$(1).o: $(objgenerated)/assembly.inc
 
+# The '.' include path is needed for the generated assembly.inc file.
+$(1)-S-ccopts += -I.
+
 $$(objcbfs)/$(1).debug: $$$$($(1)-libs) $$$$($(1)-objs)
 	@printf "    LINK       $$(subst $$(obj)/,,$$(@))\n"
 	$$(LD_$(1)) $$(LDFLAGS_$(1)) -o $$@ -L$$(obj) $$(COMPILER_RT_FLAGS_$(1)) --whole-archive --start-group $$(filter-out %.ld,$$($(1)-objs)) $$($(1)-libs) --no-whole-archive $$(COMPILER_RT_$(1)) --end-group -T $$(obj)/arch/x86/memlayout.$(1).ld --oformat $(2)
@@ -157,6 +160,35 @@ $$(objcbfs)/$(1).debug: $$$$($(1)-libs) $$$$($(1)-objs)
 endef
 
 ###############################################################################
+# verstage
+###############################################################################
+
+ifeq ($(CONFIG_ARCH_VERSTAGE_X86_32)$(CONFIG_ARCH_VERSTAGE_X86_64),y)
+
+verstage-y += boot.c
+
+verstage-$(CONFIG_ARCH_RAMSTAGE_X86_32) += cpu_common.c
+verstage-y += memset.c
+verstage-y += memcpy.c
+verstage-y += memmove.c
+verstage-y += mmap_boot.c
+
+verstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
+
+verstage-libs += $(objgenerated)/libverstage.a
+
+ifeq ($(CONFIG_ARCH_VERSTAGE_X86_32),y)
+$(eval $(call early_x86_stage,verstage,elf32-i386))
+else
+$(eval $(call early_x86_stage,verstage,elf64-x86-64))
+endif
+
+# Verstage on x86 expected to be xip.
+CBFSTOOL_VERSTAGE_OPTS  = -a 64 --xip -S ".car.data"
+
+endif # CONFIG_ARCH_VERSTAGE_X86_32 / CONFIG_ARCH_VERSTAGE_X86_64
+
+###############################################################################
 # romstage
 ###############################################################################
 
@@ -211,7 +243,7 @@ $(eval $(call early_x86_stage,romstage,elf64-x86-64))
 endif
 
 # Compiling crt0 with -g seems to trigger https://sourceware.org/bugzilla/show_bug.cgi?id=6428
-romstage-S-ccopts += -I. -g0
+romstage-S-ccopts += -g0
 
 endif # CONFIG_ARCH_ROMSTAGE_X86_32 / CONFIG_ARCH_ROMSTAGE_X86_64
 
diff --git a/src/arch/x86/bootblock_simple.c b/src/arch/x86/bootblock_simple.c
index adeecf7ba6..bb0591fb53 100644
--- a/src/arch/x86/bootblock_simple.c
+++ b/src/arch/x86/bootblock_simple.c
@@ -15,7 +15,12 @@ static void main(unsigned long bist)
 #endif
 	}
 
+#if CONFIG_SEPARATE_VERSTAGE
+	const char* target1 = "fallback/verstage";
+#else
 	const char* target1 = "fallback/romstage";
+#endif
+
 	unsigned long entry;
 	entry = findstage(target1);
 	if (entry) call(entry, bist);
diff --git a/src/arch/x86/car.ld b/src/arch/x86/car.ld
index 5da9dcf32f..fa297162a0 100644
--- a/src/arch/x86/car.ld
+++ b/src/arch/x86/car.ld
@@ -22,6 +22,11 @@
 /* This file is included inside a SECTIONS block */
 . = CONFIG_DCACHE_RAM_BASE;
 .car.data . (NOLOAD) : {
+	/* Vboot work buffer is completely volatile outside of verstage and
+	 * romstage. Appropriate code needs to handle the transition. */
+#if IS_ENABLED(CONFIG_SEPARATE_VERSTAGE)
+	VBOOT2_WORK(., 16K)
+#endif
 	/* The pre-ram cbmem console as well as the timestamp region are fixed
 	 * in size. Therefore place them at the beginning .car.data section
 	 * so that multiple stages (romstage and verstage) have a consistent
diff --git a/src/arch/x86/include/arch/early_variables.h b/src/arch/x86/include/arch/early_variables.h
index 7ccb340cf4..8a69fca9a0 100644
--- a/src/arch/x86/include/arch/early_variables.h
+++ b/src/arch/x86/include/arch/early_variables.h
@@ -21,6 +21,7 @@
 #define ARCH_EARLY_VARIABLES_H
 
 #include <stdlib.h>
+#include <rules.h>
 
 #if defined(__PRE_RAM__) && IS_ENABLED(CONFIG_CACHE_AS_RAM)
 asm(".section .car.global_data,\"w\",@nobits");
@@ -31,11 +32,27 @@ asm(".previous");
 #define CAR_GLOBAL __attribute__((used,section(".car.global_data#")))
 #endif /* __clang__ */
 
+/*
+ * On x86 verstage, all CAR_GLOBAL variables are accessed unconditionally
+ * because cbmem is never initialized until romstage when dram comes up.
+ */
+#if ENV_VERSTAGE
+static inline void *car_get_var_ptr(void *var)
+{
+	return var;
+}
+
+static inline void *car_sync_var_ptr(void *var)
+{
+	return var;
+}
+#else
 /* Get the correct pointer for the CAR global variable. */
 void *car_get_var_ptr(void *var);
 
 /* Get and update a CAR_GLOBAL pointing elsewhere in car.global_data*/
 void *car_sync_var_ptr(void *var);
+#endif /* ENV_VERSTAGE */
 
 /* Get and set a primitive type global variable. */
 #define car_get_var(var) \
diff --git a/src/arch/x86/include/arch/header.ld b/src/arch/x86/include/arch/header.ld
index 0262c9208d..ca9b50a326 100644
--- a/src/arch/x86/include/arch/header.ld
+++ b/src/arch/x86/include/arch/header.ld
@@ -24,8 +24,23 @@ PHDRS
 	to_load PT_LOAD;
 }
 
-#if ENV_RAMSTAGE || ENV_RMODULE
-ENTRY(_start)
-#elif ENV_ROMSTAGE
-ENTRY(protected_start)
+/*
+ * For CONFIG_SEPARATE_VERSTAGE romstage doesn't have the cache-as-ram setup.
+ * It only contains the teardown code. The verstage has the cache-as-ram setup
+ * code. Therefore, it needs the protected_start symbol as its entry point.
+ * The romstage entry will be named _start for consistency, but it's likely
+ * to be implemented in the chipset code in order to control the logic flow.
+ */
+#if IS_ENABLED(CONFIG_SEPARATE_VERSTAGE)
+	#if ENV_RAMSTAGE || ENV_RMODULE || ENV_ROMSTAGE
+	ENTRY(_start)
+	#elif ENV_VERSTAGE
+	ENTRY(protected_start)
+	#endif
+#else
+	#if ENV_RAMSTAGE || ENV_RMODULE
+	ENTRY(_start)
+	#elif ENV_ROMSTAGE
+	ENTRY(protected_start)
+	#endif
 #endif
diff --git a/src/arch/x86/include/arch/memlayout.h b/src/arch/x86/include/arch/memlayout.h
index 91cfc8e064..18e10e2cf3 100644
--- a/src/arch/x86/include/arch/memlayout.h
+++ b/src/arch/x86/include/arch/memlayout.h
@@ -22,8 +22,8 @@
 
 #include <rules.h>
 
-#if ENV_ROMSTAGE
-/* No .data or .bss in romstage. Cache as ram is handled separately. */
+#if ENV_ROMSTAGE || ENV_VERSTAGE
+/* No .data or .bss sections. Cache as ram is handled separately. */
 #define ARCH_STAGE_HAS_DATA_SECTION 0
 #define ARCH_STAGE_HAS_BSS_SECTION 0
 #endif
diff --git a/src/arch/x86/memlayout.ld b/src/arch/x86/memlayout.ld
index 475f9bc912..f6a8dc0f19 100644
--- a/src/arch/x86/memlayout.ld
+++ b/src/arch/x86/memlayout.ld
@@ -39,5 +39,12 @@ SECTIONS
 
 	/* Pull in the cache-as-ram rules. */
 	#include "car.ld"
+#elif ENV_VERSTAGE
+	/* The 1M size is not allocated. It's just for basic size checking.
+	 * Link at 32MiB address and rely on cbfstool to relocate to XIP. */
+	VERSTAGE(32M, 1M)
+
+	/* Pull in the cache-as-ram rules. */
+	#include "car.ld"
 #endif
 }