[arm-m] add initial vector table and initialization code

arch/arm/arm-m/start.c

@@ -0,0 +1,75 @@
+#include <debug.h>
+#include <compiler.h>
+#include <stdint.h>
+
+/* externals */
+extern unsigned int __data_start_rom, __data_start, __data_end;
+extern unsigned int __bss_start, __bss_end;
+
+void _nmi(void)
+{
+	printf("nmi\n");
+	halt();
+}
+
+void _hardfault(void)
+{
+	printf("hardfault\n");
+	halt();
+}
+
+void _memmanage(void)
+{
+	printf("memmanage\n");
+	halt();
+}
+
+void _busfault(void)
+{
+	printf("busfault\n");
+	halt();
+}
+
+void _usagefault(void)
+{
+	printf("usagefault\n");
+	halt();
+}
+
+void _svc(void)
+{
+	printf("svc\n");
+	halt();
+}
+
+void _pendsv(void)
+{
+	printf("pendsv\n");
+	halt();
+}
+
+void _systick(void)
+{
+	printf("systick\n");
+	halt();
+}
+
+void _start(void)
+{
+	/* copy data from rom */
+	if (&__data_start != &__data_start_rom) {
+		unsigned int *src = &__data_start_rom;
+		unsigned int *dest = &__data_start;
+
+		while (dest != &__data_end)
+			*dest++ = *src++;
+	}
+
+	/* zero out bss */
+	unsigned int *bss = &__bss_start;
+	while (bss != &__bss_end)
+		*bss++ = 0;
+
+	for (;;)
+		;
+}

arch/arm/arm-m/vectab.c

@@ -0,0 +1,41 @@
+#include <compiler.h>
+#include <stdint.h>
+
+static uint8_t initial_stack[1024];
+
+extern void _start(void);
+extern void _nmi(void);
+extern void _hardfault(void);
+extern void _memmanage(void);
+extern void _busfault(void);
+extern void _usagefault(void);
+extern void _svc(void);
+extern void _pendsv(void);
+extern void _pendsv(void);
+extern void _systick(void);
+
+const void * const __SECTION(".text.boot") vectab[] =
+{
+	/* arm exceptions */
+	initial_stack + sizeof(initial_stack),
+	_start,
+	_nmi, // nmi
+	_hardfault, // hard fault
+	_memmanage, // mem manage
+	_busfault, // bus fault
+	_usagefault, // usage fault
+	0, // reserved
+	0, // reserved
+	0, // reserved
+	0, // reserved
+	_svc, // svcall
+	0, // debug monitor
+	0, // reserved
+	_pendsv, // pendsv
+	_systick, // systick
+
+	// XXX include irq init from platform space here
+};
+
+
+

arch/arm/rules.mk

@@ -117,6 +117,7 @@ OBJS += \
 endif
 ifeq ($(SUBARCH),arm-m)
 OBJS += \
+	$(LOCAL_DIR)/arm-m/vectab.o \
 	$(LOCAL_DIR)/arm-m/start.o \
 	$(LOCAL_DIR)/arm-m/thread.o
 endif

arch/arm/system-onesegment.ld

@@ -7,7 +7,7 @@ SECTIONS
 	. = %MEMBASE%;
 
 	/* text/read-only data */
-	.text.boot : { *(.text.boot) }
+	.text.boot : { KEEP(*(.text.boot)) }
 	.text :	{ *(.text .text.* .glue_7* .gnu.linkonce.t.*) } =0x9090
 
 	.interp : { *(.interp) }
@@ -73,6 +73,7 @@ SECTIONS
 	.bss : { *(.bss .bss.*) }
 
 	. = ALIGN(4); 
+	__bss_end = .;
 	_end = .;
 
 	. = %MEMBASE% + %MEMSIZE%;

arch/arm/system-twosegment.ld

@@ -7,7 +7,7 @@ SECTIONS
 	. = %ROMBASE%;
 
 	/* text/read-only data */
-	.text.boot : { *(.text.boot) }
+	.text.boot : { KEEP(*(.text.boot)) }
 	.text :	{ *(.text .text.* .glue_7* .gnu.linkonce.t.*) } =0x9090
 
 	.interp : { *(.interp) }
@@ -76,6 +76,7 @@ SECTIONS
 	.bss : { *(.bss .bss.*) }
 
 	. = ALIGN(4); 
+	__bss_end = .;
 	_end = . ;
 
 	. = %MEMBASE% + %MEMSIZE%;