riscv: separately define stack locations at different stages

BOOTBLOCK/ROMSTAGE run in CAR/scratchpad. When RAMSTAGE begins
execution will enable cache, then CAR will disappear. So the
Stack will be separated.

Change-Id: I37a0c1928052cabf61ba5c25b440363b75726782
Signed-off-by: Xiang Wang <wxjstz@126.com>
Reviewed-on: https://review.coreboot.org/28383
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
diff --git a/src/arch/riscv/include/arch/memlayout.h b/src/arch/riscv/include/arch/memlayout.h
index 9097cf5..7baab76 100644
--- a/src/arch/riscv/include/arch/memlayout.h
+++ b/src/arch/riscv/include/arch/memlayout.h
@@ -20,6 +20,20 @@
 
 #define STACK(addr, size) REGION(stack, addr, size, 4096)
 
+#if defined(__PRE_RAM__)
+	#define CAR_STACK(addr, size) \
+		REGION(car_stack, addr, size, 4K) \
+		ALIAS_REGION(car_stack, stack)
+	#define MEM_STACK(addr, size) \
+		REGION(mem_stack, addr, size, 4K)
+#else
+	#define CAR_STACK(addr, size) \
+		REGION(car_stack, addr, size, 4K)
+	#define MEM_STACK(addr, size) \
+		REGION(mem_stack, addr, size, 4K) \
+		ALIAS_REGION(mem_stack, stack)
+#endif
+
 /* TODO: Need to add DMA_COHERENT region like on ARM? */
 
 #endif /* __ARCH_MEMLAYOUT_H */
diff --git a/src/soc/sifive/fu540/include/soc/memlayout.ld b/src/soc/sifive/fu540/include/soc/memlayout.ld
index a03c03d..b9b9c47 100644
--- a/src/soc/sifive/fu540/include/soc/memlayout.ld
+++ b/src/soc/sifive/fu540/include/soc/memlayout.ld
@@ -25,11 +25,12 @@
 {
 	L2LIM_START(FU540_L2LIM)
 	BOOTBLOCK(FU540_L2LIM, 64K)
-	STACK(FU540_L2LIM + 64K, 4K)
-	PRERAM_CBMEM_CONSOLE(FU540_L2LIM + 68K, 8K)
+	CAR_STACK(FU540_L2LIM + 64K, 20K)
+	PRERAM_CBMEM_CONSOLE(FU540_L2LIM + 84K, 8K)
 	ROMSTAGE(FU540_L2LIM + 128K, 128K)
 	L2LIM_END(FU540_L2LIM + 2M)
 
 	DRAM_START(FU540_DRAM)
 	RAMSTAGE(FU540_DRAM, 256K)
+	MEM_STACK(FU540_DRAM + 256K, 20K)
 }