os-workshop

commit f5a30bda1c5b2fea531e640cf28082d6450b7fb0
parent 49205eea2c24cca81c2bbbbb7686edeb7a6592d7
Author: Brian Swetland <swetland@frotz.net>
Date:   Sat, 14 May 2022 16:24:17 -0700

build: fix some linker/init issues

- fix infinite loop in zero bss in start.S
- include .sdata* and .sbss* sections properly
- make elf targets depend on hw/common.ram.ld
- adjust cpu target to RV32IMA

Diffstat:
M
Makefile
 | 
2
+-
M
hw/common.ram.ld
 | 
2
++
M
hw/src/start.S
 | 
2
+-
M
make/app.mk
 | 
4
++--

4 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/Makefile b/Makefile
@@ -32,7 +32,7 @@ XOBJDUMP := $(XTOOLCHAIN)objdump
 XOBJCOPY := $(XTOOLCHAIN)objcopy
 XAR := $(XTOOLCHAIN)ar
 
-ARCHFLAGS := -march=rv32im -mabi=ilp32 -mcmodel=medany
+ARCHFLAGS := -march=rv32ima -mabi=ilp32 -mcmodel=medany
 ARCHFLAGS += -static -nostdlib -nostartfiles -ffreestanding
 ARCHFLAGS += -ffunction-sections -fdata-sections
 ARCHFLAGS += -fno-builtin -fno-strict-aliasing
diff --git a/hw/common.ram.ld b/hw/common.ram.ld
@@ -28,12 +28,14 @@ SECTIONS {
 		*(.data .data.* .gnu.linkonce.d.*)
 		*(.got*)
 		*(.dynamic)
+		*(.sdata .sdata.*)
 		. = ALIGN(4);
 		__data_end = .;
 	} > RAM
 
 	.bss : {
 		__bss_start = .;
+		*(.sbss .sbss.*)
 		*(.bss .bss.*)
 		*(.gnu.linkonce.b.*)
 		. = ALIGN(4);
diff --git a/hw/src/start.S b/hw/src/start.S
@@ -13,7 +13,7 @@ _start:
 zero_loop:
 	beq t0, t1, zero_done
 	sw zero, 0(t0)
-	add a0, a0, 4
+	add t0, t0, 4
 	j zero_loop
 zero_done:
 
diff --git a/make/app.mk b/make/app.mk
@@ -12,12 +12,12 @@ ALL += $(MOD_ELF) $(MOD_LST) $(MOD_BIN)
 
 include make/rules.mk
 
-$(MOD_ELF): $(MOD_DIR)/build.opts $(patsubst %,$(BUILD)/lib%.a,$(MOD_LIB))
+$(MOD_ELF): $(MOD_DIR)/build.opts $(patsubst %,$(BUILD)/lib%.a,$(MOD_LIB)) 
 
 $(MOD_ELF): _OBJ := $(MOD_OBJ)
 $(MOD_ELF): _LDFLAGS := $(MOD_LDFLAGS) -T $(MOD_LDSCRIPT)
 $(MOD_ELF): _LIB := -L$(BUILD) $(patsubst %,-l%,$(MOD_LIB)) -lgcc
-$(MOD_ELF): $(MOD_OBJ) $(MOD_LDSCRIPT) 
+$(MOD_ELF): $(MOD_OBJ) $(MOD_LDSCRIPT) hw/common.ram.ld
 	@$(info linking $@)
 	$(V)$(XGCC) $(_LDFLAGS) -o $@ $(_OBJ) $(_LIB)