memlayout: Store region sizes as separate symbols

This patch changes the memlayout macro infrastructure so that the size
of a region "xxx" (i.e. the distance between the symbols _xxx and _exxx)
is stored in a separate _xxx_size symbol. This has the advantage that
region sizes can be used inside static initializers, and also saves an
extra subtraction at runtime. Since linker symbols can only be treated
as addresses (not as raw integers) by C, retain the REGION_SIZE()
accessor macro to hide the necessary typecast.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: Ifd89708ca9bd3937d0db7308959231106a6aa373
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49332
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

2 files changed, 26 insertions, 7 deletions

diff --git a/src/include/memlayout.h b/src/include/memlayout.h
index 424a28a20a..1e9fca8198 100644
--- a/src/include/memlayout.h
+++ b/src/include/memlayout.h
@@ -33,22 +33,33 @@
 	SET_COUNTER(name, addr) \
 	_##name = ABSOLUTE(.);
 
+#define RECORD_SIZE(name) \
+	_##name##_size = ABSOLUTE(_e##name - _##name);
+
 #define REGION(name, addr, size, expected_align) \
 	SYMBOL(name, addr) \
 	_ = ASSERT(. == ALIGN(expected_align), \
 		STR(name must be aligned to expected_align!)); \
-	SYMBOL(e##name, addr + size)
+	SYMBOL(e##name, addr + size) \
+	RECORD_SIZE(name)
 
 #define ALIAS_REGION(name, alias) \
 	_##alias = ABSOLUTE(_##name); \
 	_e##alias = ABSOLUTE(_e##name); \
+	RECORD_SIZE(alias)
+
+#define REGION_START(name, addr) SYMBOL(name, addr)
+
+#define REGION_END(name, addr) \
+	SYMBOL(e##name, addr) \
+	RECORD_SIZE(name)
 
 /* Declare according to SRAM/DRAM ranges in SoC hardware-defined address map. */
-#define SRAM_START(addr) SYMBOL(sram, addr)
+#define SRAM_START(addr) REGION_START(sram, addr)
 
-#define SRAM_END(addr) SYMBOL(esram, addr)
+#define SRAM_END(addr) REGION_END(sram, addr)
 
-#define DRAM_START(addr) SYMBOL(dram, addr)
+#define DRAM_START(addr) REGION_START(dram, addr)
 
 #define TIMESTAMP(addr, size) \
 	REGION(timestamp, addr, size, 8) \
@@ -93,6 +104,7 @@
 	#define DECOMPRESSOR(addr, sz) \
 		SYMBOL(decompressor, addr) \
 		_edecompressor = ABSOLUTE(_decompressor + sz); \
+		RECORD_SIZE(decompressor) \
 		_ = ASSERT(_eprogram - _program <= sz, \
 			STR(decompressor exceeded its allotted size! (sz))); \
 		INCLUDE "decompressor/lib/program.ld"
@@ -113,6 +125,7 @@
 	#define BOOTBLOCK(addr, sz) \
 		SYMBOL(bootblock, addr) \
 		_ebootblock = ABSOLUTE(_bootblock + sz); \
+		RECORD_SIZE(bootblock) \
 		_ = ASSERT(_eprogram - _program <= sz, \
 			STR(Bootblock exceeded its allotted size! (sz))); \
 		INCLUDE "bootblock/lib/program.ld"
@@ -125,6 +138,7 @@
 	#define ROMSTAGE(addr, sz) \
 		SYMBOL(romstage, addr) \
 		_eromstage = ABSOLUTE(_romstage + sz); \
+		RECORD_SIZE(romstage) \
 		_ = ASSERT(_eprogram - _program <= sz, \
 			STR(Romstage exceeded its allotted size! (sz))); \
 		INCLUDE "romstage/lib/program.ld"
@@ -137,6 +151,7 @@
 	#define RAMSTAGE(addr, sz) \
 		SYMBOL(ramstage, addr) \
 		_eramstage = ABSOLUTE(_ramstage + sz); \
+		RECORD_SIZE(ramstage) \
 		_ = ASSERT(_eprogram - _program <= sz, \
 			STR(Ramstage exceeded its allotted size! (sz))); \
 		INCLUDE "ramstage/lib/program.ld"
@@ -161,6 +176,7 @@
 	#define VERSTAGE(addr, sz) \
 		SYMBOL(verstage, addr) \
 		_everstage = ABSOLUTE(_verstage + sz); \
+		RECORD_SIZE(verstage) \
 		_ = ASSERT(_eprogram - _program <= sz, \
 			STR(Verstage exceeded its allotted size! (sz))); \
 		INCLUDE "verstage/lib/program.ld"
@@ -180,6 +196,7 @@
 	#define POSTCAR(addr, sz) \
 		SYMBOL(postcar, addr) \
 		_epostcar = ABSOLUTE(_postcar + sz); \
+		RECORD_SIZE(postcar) \
 		_ = ASSERT(_eprogram - _program <= sz, \
 			STR(Aftercar exceeded its allotted size! (sz))); \
 		INCLUDE "postcar/lib/program.ld"
diff --git a/src/include/symbols.h b/src/include/symbols.h
index 6fe24f5e44..fe449d9b4f 100644
--- a/src/include/symbols.h
+++ b/src/include/symbols.h
@@ -7,11 +7,12 @@
 
 extern u8 _dram[];
 
-#define REGION_SIZE(name) (_e##name - _##name)
+#define REGION_SIZE(name) ((size_t)_##name##_size)
 
 #define DECLARE_REGION(name)	\
 	extern u8 _##name[];	\
-	extern u8 _e##name[];
+	extern u8 _e##name[];	\
+	extern u8 _##name##_size[];
 
 /*
  * Regions can be declared optional if not all configurations provide them in
@@ -23,7 +24,8 @@ extern u8 _dram[];
  */
 #define DECLARE_OPTIONAL_REGION(name)	\
 	__weak extern u8 _##name[];	\
-	__weak extern u8 _e##name[];
+	__weak extern u8 _e##name[];	\
+	__weak extern u8 _##name##_size[];
 
 DECLARE_REGION(sram)
 DECLARE_OPTIONAL_REGION(timestamp)