common/system: refactor some confusing ifdefs

I had a hard time reading this section, so figured I may as well
rewrite it to use IS_ENABLED while I was here.

Gave CONFIG_{RO,RW}_HEAD_ROOM a default value of zero here, which
makes the math work out for boards without it anyway.

BUG=none
BRANCH=none
TEST=buildall

Change-Id: I87dc2d73838c350088916b57aa51d5f368c5592f
Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1727570
Reviewed-by: Denis Brockus <dbrockus@chromium.org>

5 files changed, 28 insertions, 33 deletions

diff --git a/chip/g/config_chip.h b/chip/g/config_chip.h
index 36b88697b1..493cb0eb0f 100644
--- a/chip/g/config_chip.h
+++ b/chip/g/config_chip.h
@@ -29,7 +29,10 @@
 #define CONFIG_PROGRAM_MEMORY_BASE     0x40000
 #define CONFIG_FLASH_SIZE              (512 * 1024)
 #define CONFIG_FLASH_ERASED_VALUE32    (-1U)
+
+#undef CONFIG_RO_HEAD_ROOM
 #define CONFIG_RO_HEAD_ROOM	       1024	/* Room for ROM signature. */
+#undef CONFIG_RW_HEAD_ROOM
 #define CONFIG_RW_HEAD_ROOM	       CONFIG_RO_HEAD_ROOM  /* same for RW */
 
 /* Memory-mapped internal flash */
diff --git a/common/system.c b/common/system.c
index 0c1a958cfc..fec9b63380 100644
--- a/common/system.c
+++ b/common/system.c
@@ -598,30 +598,27 @@ test_mockable int system_run_image_copy(enum system_image_copy_t copy)
 	if (base == 0xffffffff)
 		return EC_ERROR_INVAL;
 
-#ifdef CONFIG_EXTERNAL_STORAGE
-	/* Jump to loader */
-	init_addr = system_get_lfw_address();
-	system_set_image_copy(copy);
-#else
-#ifdef CONFIG_FW_RESET_VECTOR
-	/* Get reset vector */
-	init_addr = system_get_fw_reset_vector(base);
-#else
-#if defined(CONFIG_RO_HEAD_ROOM)
-	/* Skip any head room in the RO image */
-	if (copy == SYSTEM_IMAGE_RO)
-		/* Don't change base, though! */
-		init_addr = *(uintptr_t *)(base + CONFIG_RO_HEAD_ROOM + 4);
-	else
-#endif
-	init_addr = *(uintptr_t *)(base + 4);
-#endif
-#ifndef EMU_BUILD
-	/* Make sure the reset vector is inside the destination image */
-	if (init_addr < base || init_addr >= base + get_size(copy))
-		return EC_ERROR_UNKNOWN;
-#endif
-#endif
+	if (IS_ENABLED(CONFIG_EXTERNAL_STORAGE)) {
+		/* Jump to loader */
+		init_addr = system_get_lfw_address();
+		system_set_image_copy(copy);
+	} else if (IS_ENABLED(CONFIG_FW_RESET_VECTOR)) {
+		/* Get reset vector */
+		init_addr = system_get_fw_reset_vector(base);
+	} else {
+		uintptr_t init = base + 4;
+
+		/* Skip any head room in the RO image */
+		if (copy == SYSTEM_IMAGE_RO)
+			init += CONFIG_RO_HEAD_ROOM;
+
+		init_addr = *(uintptr_t *)(init);
+
+		/* Make sure the reset vector is inside the destination image */
+		if (!IS_ENABLED(EMU_BUILD) &&
+		    (init_addr < base || init_addr >= base + get_size(copy)))
+			return EC_ERROR_UNKNOWN;
+	}
 
 	CPRINTS("Jumping to image %s", system_image_copy_t_to_string(copy));
 
diff --git a/core/cortex-m/ec.lds.S b/core/cortex-m/ec.lds.S
index 93eb70550b..90ba292c5b 100644
--- a/core/cortex-m/ec.lds.S
+++ b/core/cortex-m/ec.lds.S
@@ -80,10 +80,10 @@ SECTIONS
     } > SHARED_LIB
 #endif
     .text : {
-#if defined(SECTION_IS_RO) && defined(CONFIG_RO_HEAD_ROOM)
+#ifdef SECTION_IS_RO
 	. = . +  CONFIG_RO_HEAD_ROOM;
 #endif
-#if defined(SECTION_IS_RW) && defined(CONFIG_RW_HEAD_ROOM)
+#ifdef SECTION_IS_RW
 	. = . +  CONFIG_RW_HEAD_ROOM;
 #endif
         *(.text.vecttable)
diff --git a/include/config.h b/include/config.h
index 723347b12a..5b7c6661ce 100644
--- a/include/config.h
+++ b/include/config.h
@@ -4155,8 +4155,8 @@
  * If needed to allocate some free space in the base of the RO or RW section
  * of the image, define these to be equal the required size of the free space.
  */
-#undef CONFIG_RO_HEAD_ROOM
-#undef CONFIG_RW_HEAD_ROOM
+#define CONFIG_RO_HEAD_ROOM 0
+#define CONFIG_RW_HEAD_ROOM 0
 
 /* Firmware upgrade options. */
 /* Firmware updates using other than HC channel(s). */
diff --git a/include/system.h b/include/system.h
index 8145fdd491..d09d4121b3 100644
--- a/include/system.h
+++ b/include/system.h
@@ -552,7 +552,6 @@ void system_set_rtc_alarm(uint32_t seconds, uint32_t microseconds);
  */
 void system_reset_rtc_alarm(void);
 
-#ifdef CONFIG_EXTERNAL_STORAGE
 /**
  * Return address of little FW to prepare for sysjump
  *
@@ -581,16 +580,12 @@ void system_set_image_copy(enum system_image_copy_t copy);
  */
 enum system_image_copy_t system_get_shrspi_image_copy(void);
 
-#endif
-
-#ifdef CONFIG_FW_RESET_VECTOR
 /**
  * Determine reset vector will be jumped to the assigned address.
  *
  * @return The address of the reset vector for RO/RW firmware image jump.
  */
 uintptr_t system_get_fw_reset_vector(uintptr_t base);
-#endif
 
 /**
  * Check if the EC is warm booting.