lib/fmap: Add optional pre-RAM cache

This patch adds an optional pre-RAM cache for the FMAP which most
platforms should be able to use, complementing the recently added
post-RAM FMAP cache in CBMEM. vboot systems currently read the FMAP
about half a dozen times from flash in verstage, which will all be
coalesced into a single read with this patch. It will also help
future vboot improvements since when FMAP reads become "free" vboot
doesn't need to keep track of so much information separately.

In order to make sure we have a single, well-defined point where the new
cache is first initialized, eliminate the build-time hardcoding of the
CBFS section offsets, so that all CBFS accesses explicitly read the
FMAP.

Add FMAP_CACHEs to all platforms that can afford it (other than the
RISC-V things where I have no idea how they work), trying to take the
space from things that look like they were oversized anyway (pre-RAM
consoles and CBFS caches).

Change-Id: I2820436776ef620bdc4481b5cd4b6957764248ea
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36657
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Joel Kitching <kitching@google.com>
diff --git a/Makefile.inc b/Makefile.inc
index 8ecc0ef..8de54a0 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -226,7 +226,7 @@
 # Add handler to copy linker scripts
 define generic-objs_ld_template_gen
 de$(EMPTY)fine $(1)-objs_ld_template
-$$(call src-to-obj,$1,$$(1).ld): $$(1).ld $(obj)/config.h
+$$(call src-to-obj,$1,$$(1).ld): $$(1).ld $(obj)/config.h $(obj)/fmap_config.h
 	@printf "    CP         $$$$(subst $$$$(obj)/,,$$$$(@))\n"
 	$$(CC_$(1)) -MMD $$(CPPFLAGS_$(1)) $$($(1)-ld-ccopts) $(PREPROCESS_ONLY) -include $(obj)/config.h -MT $$$$@ -o $$$$@ $$$$<
 en$(EMPTY)def
diff --git a/src/arch/x86/car.ld b/src/arch/x86/car.ld
index 74fc74b..972cb52 100644
--- a/src/arch/x86/car.ld
+++ b/src/arch/x86/car.ld
@@ -58,6 +58,7 @@
 #endif
 
 	TIMESTAMP(., 0x200)
+	FMAP_CACHE(., FMAP_SIZE)
 
 	_car_ehci_dbg_info = .;
 	/* Reserve sizeof(struct ehci_dbg_info). */
diff --git a/src/include/memlayout.h b/src/include/memlayout.h
index 0100e27..56dfb6a 100644
--- a/src/include/memlayout.h
+++ b/src/include/memlayout.h
@@ -21,6 +21,8 @@
 #include <arch/memlayout.h>
 #include <vb2_constants.h>
 
+#include "fmap_config.h"
+
 /* Macros that the architecture can override. */
 #ifndef ARCH_POINTER_ALIGN_SIZE
 #define ARCH_POINTER_ALIGN_SIZE 8
@@ -30,7 +32,8 @@
 #define ARCH_CACHELINE_ALIGN_SIZE 64
 #endif
 
-#define STR(x) #x
+#define STR(x) XSTR(x)
+#define XSTR(x) #x
 
 #define ALIGN_COUNTER(align) \
 	. = ALIGN(align);
@@ -73,6 +76,11 @@
 	ALIAS_REGION(cbfs_cache, preram_cbfs_cache) \
 	ALIAS_REGION(cbfs_cache, postram_cbfs_cache)
 
+#define FMAP_CACHE(addr, sz) \
+	REGION(fmap_cache, addr, sz, 4) \
+	_ = ASSERT(sz == 0 || sz >= FMAP_SIZE, \
+		   STR(FMAP does not fit in FMAP_CACHE! (sz < FMAP_SIZE)));
+
 #if ENV_ROMSTAGE_OR_BEFORE
 	#define PRERAM_CBFS_CACHE(addr, size) \
 		REGION(preram_cbfs_cache, addr, size, 4) \
diff --git a/src/include/symbols.h b/src/include/symbols.h
index 56df8d5..eec4701 100644
--- a/src/include/symbols.h
+++ b/src/include/symbols.h
@@ -34,6 +34,7 @@
 DECLARE_REGION(preram_cbfs_cache)
 DECLARE_REGION(postram_cbfs_cache)
 DECLARE_REGION(cbfs_cache)
+DECLARE_REGION(fmap_cache)
 DECLARE_REGION(payload)
 
 /* "program" always refers to the current execution unit. */
diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index 3b7d57c..dc0c46d 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -208,13 +208,6 @@
 $(call src-to-obj,verstage,$(dir)/version.c) : $(obj)/build.h
 $(call src-to-obj,postcar,$(dir)/version.c) : $(obj)/build.h
 
-$(call src-to-obj,bootblock,$(dir)/cbfs.c) : $(obj)/fmap_config.h
-$(call src-to-obj,romstage,$(dir)/cbfs.c) : $(obj)/fmap_config.h
-$(call src-to-obj,ramstage,$(dir)/cbfs.c) : $(obj)/fmap_config.h
-$(call src-to-obj,smm,$(dir)/cbfs.c) : $(obj)/fmap_config.h
-$(call src-to-obj,verstage,$(dir)/cbfs.c) : $(obj)/fmap_config.h
-$(call src-to-obj,postcar,$(dir)/cbfs.c) : $(obj)/fmap_config.h
-
 $(call src-to-obj,bootblock,$(dir)/fmap.c) : $(obj)/fmap_config.h
 $(call src-to-obj,romstage,$(dir)/fmap.c) : $(obj)/fmap_config.h
 $(call src-to-obj,ramstage,$(dir)/fmap.c) : $(obj)/fmap_config.h
diff --git a/src/lib/cbfs.c b/src/lib/cbfs.c
index 1601f20..27a1592 100644
--- a/src/lib/cbfs.c
+++ b/src/lib/cbfs.c
@@ -26,7 +26,6 @@
 #include <symbols.h>
 #include <timestamp.h>
 #include <fmap.h>
-#include "fmap_config.h"
 #include <security/vboot/vboot_crtm.h>
 
 #define ERROR(x...) printk(BIOS_ERR, "CBFS: " x)
@@ -310,7 +309,10 @@
 	if (bdev == NULL)
 		return -1;
 
-	size_t fmap_top = ___FMAP__COREBOOT_BASE + ___FMAP__COREBOOT_SIZE;
+	struct region fmap_region;
+	if (fmap_locate_area("COREBOOT", &fmap_region))
+		return -1;
+	size_t fmap_top = region_end(&fmap_region);
 
 	/* Find location of header using signed 32-bit offset from
 	 * end of CBFS region. */
diff --git a/src/lib/fmap.c b/src/lib/fmap.c
index f3ff071..4b4179c 100644
--- a/src/lib/fmap.c
+++ b/src/lib/fmap.c
@@ -15,12 +15,13 @@
 
 #include <arch/early_variables.h>
 #include <boot_device.h>
+#include <cbmem.h>
 #include <console/console.h>
 #include <fmap.h>
 #include <commonlib/fmap_serialized.h>
 #include <stddef.h>
 #include <string.h>
-#include <cbmem.h>
+#include <symbols.h>
 
 #include "fmap_config.h"
 
@@ -31,26 +32,94 @@
 static int fmap_print_once CAR_GLOBAL;
 static struct mem_region_device fmap_cache CAR_GLOBAL;
 
+#define print_once(...) do { \
+		if (!car_get_var(fmap_print_once)) \
+			printk(__VA_ARGS__); \
+	} while (0)
+
+DECLARE_OPTIONAL_REGION(fmap_cache);
+
 uint64_t get_fmap_flash_offset(void)
 {
 	return FMAP_OFFSET;
 }
 
+static int check_signature(const struct fmap *fmap)
+{
+	return memcmp(fmap->signature, FMAP_SIGNATURE, sizeof(fmap->signature));
+}
+
+static void report(const struct fmap *fmap)
+{
+	print_once(BIOS_DEBUG, "FMAP: Found \"%s\" version %d.%d at %#x.\n",
+	       fmap->name, fmap->ver_major, fmap->ver_minor, FMAP_OFFSET);
+	print_once(BIOS_DEBUG, "FMAP: base = %#llx size = %#x #areas = %d\n",
+	       (long long)fmap->base, fmap->size, fmap->nareas);
+	car_set_var(fmap_print_once, 1);
+}
+
+static void setup_preram_cache(struct mem_region_device *cache_mrdev)
+{
+	if (!ENV_ROMSTAGE_OR_BEFORE) {
+		/* We get here if ramstage makes an FMAP access before calling
+		   cbmem_initialize(). We should avoid letting it come to that,
+		   so print a warning. */
+		print_once(BIOS_WARNING,
+			"WARNING: Post-RAM FMAP access too early for cache!\n");
+		return;
+	}
+
+	if (REGION_SIZE(fmap_cache) == 0) {
+		/* If you see this you really want to add an FMAP_CACHE to your
+		   memlayout, unless you absolutely can't affort the 2K. */
+		print_once(BIOS_NOTICE,
+			"NOTE: Running without FMAP_CACHE, should add it!\n");
+		return;
+	}
+
+	struct fmap *fmap = (struct fmap *)_fmap_cache;
+	if (!ENV_BOOTBLOCK) {
+		/* NOTE: This assumes that for all platforms running this code,
+		   the bootblock is the first stage and the bootblock will make
+		   at least one FMAP access (usually from finding CBFS). */
+		if (!check_signature(fmap))
+			goto register_cache;
+
+		printk(BIOS_ERR, "ERROR: FMAP cache corrupted?!\n");
+	}
+
+	/* In case we fail below, make sure the cache is invalid. */
+	memset(fmap->signature, 0, sizeof(fmap->signature));
+
+	boot_device_init();
+	const struct region_device *boot_rdev = boot_device_ro();
+	if (!boot_rdev)
+		return;
+
+	/* memlayout statically guarantees that the FMAP_CACHE is big enough. */
+	if (rdev_readat(boot_rdev, fmap, FMAP_OFFSET, FMAP_SIZE) != FMAP_SIZE)
+		return;
+	if (check_signature(fmap))
+		return;
+	report(fmap);
+
+register_cache:
+	mem_region_device_ro_init(cache_mrdev, fmap, FMAP_SIZE);
+}
+
 static int find_fmap_directory(struct region_device *fmrd)
 {
 	const struct region_device *boot;
 	struct fmap *fmap;
-	size_t fmap_size;
+	struct mem_region_device *cache;
 	size_t offset = FMAP_OFFSET;
 
-	if (cbmem_possibly_online() && !ENV_SMM) {
-		/* Try FMAP cache first */
-		const struct mem_region_device *cache;
-
-		cache = car_get_var_ptr(&fmap_cache);
-		if (region_device_sz(&cache->rdev))
-			return rdev_chain_full(fmrd, &cache->rdev);
-	}
+	/* Try FMAP cache first */
+	cache = car_get_var_ptr(&fmap_cache);
+	if (!region_device_sz(&cache->rdev))
+		setup_preram_cache(cache);
+	if (region_device_sz(&cache->rdev))
+		return rdev_chain_full(fmrd, &cache->rdev);
 
 	boot_device_init();
 	boot = boot_device_ro();
@@ -58,32 +127,22 @@
 	if (boot == NULL)
 		return -1;
 
-	fmap_size = sizeof(struct fmap);
-
-	fmap = rdev_mmap(boot, offset, fmap_size);
+	fmap = rdev_mmap(boot, offset, sizeof(struct fmap));
 
 	if (fmap == NULL)
 		return -1;
 
-	if (memcmp(fmap->signature, FMAP_SIGNATURE, sizeof(fmap->signature))) {
+	if (check_signature(fmap)) {
 		printk(BIOS_DEBUG, "No FMAP found at %zx offset.\n", offset);
 		rdev_munmap(boot, fmap);
 		return -1;
 	}
 
-	if (!car_get_var(fmap_print_once)) {
-		printk(BIOS_DEBUG, "FMAP: Found \"%s\" version %d.%d at %zx.\n",
-		       fmap->name, fmap->ver_major, fmap->ver_minor, offset);
-		printk(BIOS_DEBUG, "FMAP: base = %llx size = %x #areas = %d\n",
-		       (long long)fmap->base, fmap->size, fmap->nareas);
-		car_set_var(fmap_print_once, 1);
-	}
-
-	fmap_size += fmap->nareas * sizeof(struct fmap_area);
+	report(fmap);
 
 	rdev_munmap(boot, fmap);
 
-	return rdev_chain(fmrd, boot, offset, fmap_size);
+	return rdev_chain(fmrd, boot, offset, FMAP_SIZE);
 }
 
 int fmap_locate_area_as_rdev(const char *name, struct region_device *area)
@@ -212,7 +271,7 @@
 	return rdev_writeat(&rdev, buffer, 0, size);
 }
 
-static void fmap_register_cache(int unused)
+static void fmap_register_cbmem_cache(int unused)
 {
 	const struct cbmem_entry *e;
 	struct mem_region_device *mdev;
@@ -232,7 +291,7 @@
  * The main reason to copy the FMAP into CBMEM is to make it available to the
  * OS on every architecture. As side effect use the CBMEM copy as cache.
  */
-static void fmap_setup_cache(int unused)
+static void fmap_setup_cbmem_cache(int unused)
 {
 	struct region_device fmrd;
 
@@ -255,9 +314,9 @@
 	}
 
 	/* Finally advertise the cache for the current stage */
-	fmap_register_cache(unused);
+	fmap_register_cbmem_cache(unused);
 }
 
-ROMSTAGE_CBMEM_INIT_HOOK(fmap_setup_cache)
-RAMSTAGE_CBMEM_INIT_HOOK(fmap_register_cache)
-POSTCAR_CBMEM_INIT_HOOK(fmap_register_cache)
+ROMSTAGE_CBMEM_INIT_HOOK(fmap_setup_cbmem_cache)
+RAMSTAGE_CBMEM_INIT_HOOK(fmap_register_cbmem_cache)
+POSTCAR_CBMEM_INIT_HOOK(fmap_register_cbmem_cache)
diff --git a/src/soc/mediatek/mt8173/include/soc/memlayout.ld b/src/soc/mediatek/mt8173/include/soc/memlayout.ld
index adda86e..2358c39 100644
--- a/src/soc/mediatek/mt8173/include/soc/memlayout.ld
+++ b/src/soc/mediatek/mt8173/include/soc/memlayout.ld
@@ -40,7 +40,8 @@
 	SRAM_START(0x00100000)
 	VBOOT2_WORK(0x00100000, 12K)
 	VBOOT2_TPM_LOG(0x00103000, 2K)
-	PRERAM_CBMEM_CONSOLE(0x00103800, 14K)
+	FMAP_CACHE(0x00103800, 2K)
+	PRERAM_CBMEM_CONSOLE(0x00104000, 12K)
 	WATCHDOG_TOMBSTONE(0x00107000, 4)
 	PRERAM_CBFS_CACHE(0x00107004, 16K - 4)
 	TIMESTAMP(0x0010B000, 4K)
diff --git a/src/soc/mediatek/mt8183/include/soc/memlayout.ld b/src/soc/mediatek/mt8183/include/soc/memlayout.ld
index 82e404f..a8f464a 100644
--- a/src/soc/mediatek/mt8183/include/soc/memlayout.ld
+++ b/src/soc/mediatek/mt8183/include/soc/memlayout.ld
@@ -34,7 +34,8 @@
 	VBOOT2_TPM_LOG(0x00103000, 2K)
 	PRERAM_CBMEM_CONSOLE(0x00103800, 14K)
 	WATCHDOG_TOMBSTONE(0x00107000, 4)
-	PRERAM_CBFS_CACHE(0x00107004, 48K - 4)
+	PRERAM_CBFS_CACHE(0x00107004, 46K - 4)
+	FMAP_CACHE(0x00112800, 2K)
 	TIMESTAMP(0x00113000, 4K)
 	STACK(0x00114000, 16K)
 	TTB(0x00118000, 28K)
diff --git a/src/soc/nvidia/tegra124/include/soc/memlayout.ld b/src/soc/nvidia/tegra124/include/soc/memlayout.ld
index 7e2f9ec..7e2cc7ad 100644
--- a/src/soc/nvidia/tegra124/include/soc/memlayout.ld
+++ b/src/soc/nvidia/tegra124/include/soc/memlayout.ld
@@ -28,7 +28,8 @@
 	SRAM_START(0x40000000)
 	TTB(0x40000000, 16K + 32)
 	PRERAM_CBMEM_CONSOLE(0x40004020, 6K - 32)
-	PRERAM_CBFS_CACHE(0x40005800, 16K)
+	FMAP_CACHE(0x40005800, 2K)
+	PRERAM_CBFS_CACHE(0x40006000, 14K)
 	VBOOT2_WORK(0x40009800, 12K)
 	VBOOT2_TPM_LOG(0x4000D800, 2K)
 	STACK(0x4000E000, 8K)
diff --git a/src/soc/nvidia/tegra210/include/soc/memlayout.ld b/src/soc/nvidia/tegra210/include/soc/memlayout.ld
index 1134da6..b7268d1 100644
--- a/src/soc/nvidia/tegra210/include/soc/memlayout.ld
+++ b/src/soc/nvidia/tegra210/include/soc/memlayout.ld
@@ -29,7 +29,8 @@
 {
 	SRAM_START(0x40000000)
 	PRERAM_CBMEM_CONSOLE(0x40000000, 2K)
-	PRERAM_CBFS_CACHE(0x40000800, 30K)
+	FMAP_CACHE(0x40000800, 2K)
+	PRERAM_CBFS_CACHE(0x40001000, 28K)
 	VBOOT2_WORK(0x40008000, 12K)
 	VBOOT2_TPM_LOG(0x4000B000, 2K)
 #if ENV_ARM64
diff --git a/src/soc/qualcomm/ipq40xx/include/soc/memlayout.ld b/src/soc/qualcomm/ipq40xx/include/soc/memlayout.ld
index f1a7bc5..6ff1018 100644
--- a/src/soc/qualcomm/ipq40xx/include/soc/memlayout.ld
+++ b/src/soc/qualcomm/ipq40xx/include/soc/memlayout.ld
@@ -34,7 +34,8 @@
 	/* This includes bootblock image, can be reused after bootblock starts */
 /*	UBER_SBL(0x0A0C0000, 48K) */
 
-	PRERAM_CBFS_CACHE(0x0A0C0000, 93K)
+	PRERAM_CBFS_CACHE(0x0A0C0000, 92K)
+	FMAP_CACHE(0x0A0EF800, 2K)
 
 	TTB(0x0A0F0000, 16K)
 	TTB_SUBTABLES(0x0A0F4000, 4K)
diff --git a/src/soc/qualcomm/ipq806x/include/soc/memlayout.ld b/src/soc/qualcomm/ipq806x/include/soc/memlayout.ld
index 25db175..595d939 100644
--- a/src/soc/qualcomm/ipq806x/include/soc/memlayout.ld
+++ b/src/soc/qualcomm/ipq806x/include/soc/memlayout.ld
@@ -38,7 +38,8 @@
 	QCA_SHARED_RAM(2A03F000, 4K)
 */
 	STACK(0x2A040000, 16K)
-	PRERAM_CBFS_CACHE(0x2A044000, 93K)
+	PRERAM_CBFS_CACHE(0x2A044000, 91K)
+	FMAP_CACHE(0x2A05B000, 2K)
 	TTB_SUBTABLES(0x2A05B800, 2K)
 	TTB(0x2A05C000, 16K)
 	SRAM_END(0x2A060000)
diff --git a/src/soc/qualcomm/qcs405/include/soc/memlayout.ld b/src/soc/qualcomm/qcs405/include/soc/memlayout.ld
index 68642d6..dd013b5 100644
--- a/src/soc/qualcomm/qcs405/include/soc/memlayout.ld
+++ b/src/soc/qualcomm/qcs405/include/soc/memlayout.ld
@@ -39,7 +39,8 @@
 	TIMESTAMP(0x8C4F000, 1K)
 	PRERAM_CBMEM_CONSOLE(0x8C4F400, 32K)
 	PRERAM_CBFS_CACHE(0x8C57400, 70K)
-	REGION(bsram_unused, 0x8C68C00, 0xA2400, 0x100)
+	FMAP_CACHE(0x8C68C00, 2K)
+	REGION(bsram_unused, 0x8C69400, 0xA1C00, 0x100)
 	BSRAM_END(0x8D80000)
 
 	DRAM_START(0x80000000)
diff --git a/src/soc/qualcomm/sc7180/include/soc/memlayout.ld b/src/soc/qualcomm/sc7180/include/soc/memlayout.ld
index b2ee3b2..3f43419 100644
--- a/src/soc/qualcomm/sc7180/include/soc/memlayout.ld
+++ b/src/soc/qualcomm/sc7180/include/soc/memlayout.ld
@@ -43,6 +43,7 @@
 	REGION(ddr_training, 0x14850000, 8K, 4K)
 	REGION(qclib_serial_log, 0x14852000, 4K, 4K)
 	REGION(ddr_information, 0x14853000, 1K, 1K)
+	FMAP_CACHE(0x14853400, 2K)
 	REGION(dcb, 0x14870000, 16K, 4K)
 	REGION(pmic, 0x14874000, 44K, 4K)
 	REGION(limits_cfg, 0x1487F000, 4K, 4K)
diff --git a/src/soc/rockchip/rk3399/include/soc/memlayout.ld b/src/soc/rockchip/rk3399/include/soc/memlayout.ld
index 293057a..4e46e2d 100644
--- a/src/soc/rockchip/rk3399/include/soc/memlayout.ld
+++ b/src/soc/rockchip/rk3399/include/soc/memlayout.ld
@@ -33,7 +33,8 @@
 #if ENV_RAMSTAGE
 	REGION(bl31_sram, 0xFF8C0000, 64K, 1)
 #else
-	PRERAM_CBFS_CACHE(0xFF8C0000, 7K)
+	PRERAM_CBFS_CACHE(0xFF8C0000, 5K)
+	FMAP_CACHE(0xFF8C1400, 2K)
 	TIMESTAMP(0xFF8C1C00, 1K)
 	/* 0xFF8C2004 is the entry point address the masked ROM will jump to. */
 	OVERLAP_DECOMPRESSOR_VERSTAGE_ROMSTAGE(0xFF8C2004, 88K - 4)
diff --git a/src/soc/samsung/exynos5250/include/soc/memlayout.ld b/src/soc/samsung/exynos5250/include/soc/memlayout.ld
index 0bd319e..7e052f0 100644
--- a/src/soc/samsung/exynos5250/include/soc/memlayout.ld
+++ b/src/soc/samsung/exynos5250/include/soc/memlayout.ld
@@ -31,7 +31,8 @@
 	ROMSTAGE(0x2030000, 128K)
 	/* 32K hole */
 	TTB(0x2058000, 16K)
-	PRERAM_CBFS_CACHE(0x205C000, 78K)
+	PRERAM_CBFS_CACHE(0x205C000, 76K)
+	FMAP_CACHE(0x206F000, 2K)
 	VBOOT2_TPM_LOG(0x206F800, 2K)
 	VBOOT2_WORK(0x2070000, 12K)
 	STACK(0x2074000, 16K)
diff --git a/src/soc/samsung/exynos5420/include/soc/memlayout.ld b/src/soc/samsung/exynos5420/include/soc/memlayout.ld
index bc5d066..ff781d2 100644
--- a/src/soc/samsung/exynos5420/include/soc/memlayout.ld
+++ b/src/soc/samsung/exynos5420/include/soc/memlayout.ld
@@ -32,7 +32,8 @@
 	ROMSTAGE(0x2030000, 128K)
 	/* 32K hole */
 	TTB(0x2058000, 16K)
-	PRERAM_CBFS_CACHE(0x205C000, 76K)
+	PRERAM_CBFS_CACHE(0x205C000, 74K)
+	FMAP_CACHE(0x206E800, 2K)
 	STACK(0x206F000, 16K)
 	/* 1K hole for weird kernel-shared CPU/SMP state structure that doesn't
 	 * seem to be implemented right now? */
diff --git a/util/cbfstool/fmaptool.c b/util/cbfstool/fmaptool.c
index faf6508..1c01ec0 100644
--- a/util/cbfstool/fmaptool.c
+++ b/util/cbfstool/fmaptool.c
@@ -24,6 +24,7 @@
 #define STDIN_FILENAME_SENTINEL "-"
 
 #define HEADER_FMAP_OFFSET "FMAP_OFFSET"
+#define HEADER_FMAP_SIZE "FMAP_SIZE"
 
 enum fmaptool_return {
 	FMAPTOOL_EXIT_SUCCESS = 0,
@@ -83,7 +84,8 @@
 }
 
 static bool write_header(const char *out_fname,
-					const struct flashmap_descriptor *root)
+			 const struct flashmap_descriptor *root,
+			 const int fmap_size)
 {
 	assert(out_fname);
 
@@ -100,21 +102,8 @@
 
 	fputs("#ifndef FMAPTOOL_GENERATED_HEADER_H_\n", header);
 	fputs("#define FMAPTOOL_GENERATED_HEADER_H_\n\n", header);
-	fprintf(header, "#define %s %#x\n\n", HEADER_FMAP_OFFSET, fmap_offset);
-
-	/* also add defines for each CBFS-carrying fmap region: base and size */
-	cbfs_section_iterator_t cbfs_it = cbfs_sections_iterator();
-	while (cbfs_it) {
-		const struct flashmap_descriptor *item =
-				cbfs_sections_iterator_deref(cbfs_it);
-		assert(item->offset_known && item->size_known);
-		unsigned abs_base = fmd_calc_absolute_offset(root, item->name);
-		fprintf(header, "#define ___FMAP__%s_BASE 0x%x\n",
-			item->name, abs_base);
-		fprintf(header, "#define ___FMAP__%s_SIZE 0x%x\n",
-			item->name, item->size);
-		cbfs_sections_iterator_advance(&cbfs_it);
-	}
+	fprintf(header, "#define %s %#x\n", HEADER_FMAP_OFFSET, fmap_offset);
+	fprintf(header, "#define %s %#x\n\n", HEADER_FMAP_SIZE, fmap_size);
 
 	fputs("#endif\n", header);
 
@@ -245,7 +234,7 @@
 	fmap_destroy(flashmap);
 
 	if (args.header_filename &&
-			!write_header(args.header_filename, descriptor)) {
+			!write_header(args.header_filename, descriptor, size)) {
 		full_fmd_cleanup(&descriptor);
 		return FMAPTOOL_EXIT_FAILED_WRITING_HEADER;
 	}