Add exception handler. This one *does* work!

Makefile

@@ -11,7 +11,8 @@ MAKEBIN = python ../makebin.py
 TARGET = miniios.bin
 ELF = miniios.elf
 OBJECTS = start.o ipcstruct.o main.o ipc.o vsprintf.o string.o gecko.o memory.o memory_asm.o \
-	utils_asm.o utils.o ff.o diskio.o sdhc.o powerpc_elf.o powerpc.o panic.o irq.o irq_asm.o
+	utils_asm.o utils.o ff.o diskio.o sdhc.o powerpc_elf.o powerpc.o panic.o irq.o irq_asm.o \
+	exception.o exception_asm.o
 
 $(TARGET) : $(ELF) $(ELFLOADER) 
 	@echo  "MAKEBIN	$@"

exception.c

@@ -0,0 +1,87 @@
+#include "irq.h"
+#include "hollywood.h"
+#include "gecko.h"
+#include "utils.h"
+#include "ipc.h"
+#include "memory.h"
+
+const char *exceptions[] = {
+	"RESET", "UNDEFINED", "SWI", "INSTR ABORT", "DATA ABORT", "RESERVED", "IRQ", "FIQ"
+};
+
+const char *aborts[] = {
+	"UNDEFINED",
+	"Alignment",
+	"UNDEFINED",
+	"Alignment",
+	"UNDEFINED",
+	"Translation",
+	"UNDEFINED",
+	"Translation",
+	"External abort",
+	"Domain",
+	"External abort",
+	"Domain",
+	"External abort on translation (first level)",
+	"Permission",
+	"External abort on translation (second level)",
+	"Permission"
+};
+
+u8 domvalid[] = {0,0,0,0,0,0,0,1,0,1,0,1,0,1,1,1};
+
+void exc_setup_stack(void);
+
+void exception_initialize(void)
+{
+	exc_setup_stack();
+	u32 cr = get_cr();
+	cr |= 0x2; // Data alignment fault checking enable
+	set_cr(cr);
+}
+
+void exc_handler(u32 type, u32 spsr, u32 *regs)
+{
+	gecko_printf("\nException %d (%s):\n", type, exceptions[type]);
+
+	u32 pc;
+
+	switch(type) {
+		case 3:
+		case 7:
+			pc = regs[15] - 4;
+			break;
+		case 4:
+			pc = regs[15] - 8;
+			break;
+		default:
+			pc = regs[15];
+			break;
+	}
+
+	gecko_printf("Registers (%p):\n", regs);
+	gecko_printf("  R0-R3: %08x %08x %08x %08x\n", regs[0], regs[1], regs[2], regs[3]);
+	gecko_printf("  R4-R7: %08x %08x %08x %08x\n", regs[4], regs[5], regs[6], regs[7]);
+	gecko_printf(" R8-R11: %08x %08x %08x %08x\n", regs[8], regs[9], regs[10], regs[11]);
+	gecko_printf("R12-R15: %08x %08x %08x %08x\n", regs[12], regs[13], regs[14], pc);
+
+	gecko_printf("SPSR: %08x\n", spsr);
+	gecko_printf("CR:   %08x\n", get_cr());
+	gecko_printf("TTBR: %08x\n", get_ttbr());
+	gecko_printf("DACR: %08x\n", get_dacr());
+
+	if(type == 3 || type == 4) {
+		u32 fsr;
+		if(type == 3)
+			fsr = get_ifsr();
+		else
+			fsr = get_dfsr();
+		gecko_printf("Abort type: %s\n", aborts[fsr&0xf]);
+		if(domvalid[fsr&0xf])
+			gecko_printf("Domain: %d\n", (fsr>>4)&0xf);
+		if(type == 4)
+			gecko_printf("Address: 0x%08x\n", get_far());
+	}
+
+	panic(0xA3);
+}

exception.h

@@ -0,0 +1,7 @@
+#ifndef __EXCEPTION_H__
+#define __EXCEPTION_H__
+
+void exception_initialize(void);
+
+#endif
+

exception_asm.S

@@ -0,0 +1,124 @@
+.globl v_undf
+.globl v_swi
+.globl v_instr_abrt
+.globl v_data_abrt
+.globl v_reserved
+.globl v_fiq
+
+.globl exc_setup_stack
+.extern __excstack_addr
+.extern exc_handler
+
+exc_setup_stack:
+	mrs	r0, cpsr
+
+	@ Switch to FIQ mode
+	msr cpsr_c, #0xd1
+	@ Setup exception stack
+	ldr	sp, =__excstack_addr
+
+	@ Switch to SVC mode
+	msr cpsr_c, #0xd3
+	@ Setup exception stack
+	ldr	sp, =__excstack_addr
+
+	@ Switch to ABORT mode
+	msr cpsr_c, #0xd7
+	@ Setup exception stack
+	ldr	sp, =__excstack_addr
+
+	@ Switch to UNDF mode
+	msr cpsr_c, #0xdb
+	@ Setup exception stack
+	ldr	sp, =__excstack_addr
+
+	@ Restore mode
+	msr cpsr_c, r0
+	bx	lr
+
+.pool
+
+v_undf:
+	stmfd	sp!, {lr}
+	stmfd	sp, {r0-lr}^
+	sub		sp, sp, #0x3c
+	mov		r2, sp
+	mrs		r1, spsr
+	mov		r0, #1
+
+	blx		exc_handler
+
+	ldmfd	sp!, {r0-r12}
+	add		sp, sp, #8
+	movs	pc, lr
+
+v_swi:
+	stmfd	sp!, {lr}
+	stmfd	sp, {r0-lr}^
+	sub		sp, sp, #0x3c
+	mov		r2, sp
+	mrs		r1, spsr
+	mov		r0, #2
+
+	blx		exc_handler
+
+	ldmfd	sp!, {r0-r12}
+	add		sp, sp, #8
+	movs	pc, lr
+
+v_instr_abrt:
+	stmfd	sp!, {lr}
+	stmfd	sp, {r0-lr}^
+	sub		sp, sp, #0x3c
+	mov		r2, sp
+	mrs		r1, spsr
+	mov		r0, #3
+
+	blx		exc_handler
+
+	ldmfd	sp!, {r0-r12}
+	add		sp, sp, #8
+	subs	pc, lr, #4
+
+v_data_abrt:
+	stmfd	sp!, {lr}
+	stmfd	sp, {r0-lr}^
+	sub		sp, sp, #0x3c
+	mov		r2, sp
+	mrs		r1, spsr
+	mov		r0, #4
+
+	blx		exc_handler
+
+	ldmfd	sp!, {r0-r12}
+	add		sp, sp, #8
+	subs	pc, lr, #8
+
+v_reserved:
+	stmfd	sp!, {lr}
+	stmfd	sp, {r0-lr}^
+	sub		sp, sp, #0x3c
+	mov		r2, sp
+	mrs		r1, spsr
+	mov		r0, #5
+
+	blx		exc_handler
+
+	ldmfd	sp!, {r0-r12}
+	add		sp, sp, #8
+	movs	pc, lr
+
+v_fiq:
+	stmfd	sp!, {lr}
+	stmfd	sp, {r0-lr}^
+	sub		sp, sp, #0x3c
+	mov		r2, sp
+	mrs		r1, spsr
+	mov		r0, #7
+
+	blx		exc_handler
+
+	ldmfd	sp!, {r0-r12}
+	add		sp, sp, #8
+	subs	pc, lr, #4
+

main.c

@@ -12,6 +12,7 @@
 #include "powerpc_elf.h"
 #include "irq.h"
 #include "ipc.h"
+#include "exception.h"
 
 void *vector;
 
@@ -150,11 +151,11 @@ void *_main(void *base)
 	gecko_init();
 	gecko_puts("MiniIOS v0.1 loading\n");
 
+	gecko_puts("Initializing exceptions...\n");
+	exception_initialize();
 	gecko_puts("Configuring caches and MMU...\n");
 	mem_initialize();
 
-
-
 	irq_initialize();
 	irq_enable(IRQ_TIMER);
 	irq_enable(IRQ_NAND);

miniios.ld

@@ -5,6 +5,7 @@ ENTRY(_start)
 
 __stack_size = 0x800;
 __irqstack_size = 0x100;
+__excstack_size = 0x100;
 
 MEMORY {
 	sram	: ORIGIN = 0xffff0000, LENGTH = 64K
@@ -103,14 +104,28 @@ SECTIONS
 		. = . +__irqstack_size;
 		. = ALIGN(64);
 		__irqstack_addr = .;
+		__excstack_end = .;
+		. = . +__excstack_size;
+		. = ALIGN(64);
+		__excstack_addr = .;
+	} >sram2
+
+	.pagetable :
+	{
+		. = ALIGN(16384);
+		__page_table = .;
+		. = . + 16384;
 	} >sram2
 
 }
 
+PROVIDE (__page_table = __page_table);
 PROVIDE (__stack_end = __stack_end);
 PROVIDE (__stack_addr = __stack_addr);
 PROVIDE (__irqstack_end = __irqstack_end);
 PROVIDE (__irqstack_addr = __irqstack_addr);
+PROVIDE (__excstack_end = __excstack_end);
+PROVIDE (__excstack_addr = __excstack_addr);
 PROVIDE (__bss_start = __bss_start);
 PROVIDE (__bss_end = __bss_end);
 PROVIDE (__bss2_start = __bss2_start);

start.S

@@ -11,7 +11,13 @@
 .globl _start
 .globl debug_output
 
+.extern v_undf
+.extern v_swi
+.extern v_instr_abrt
+.extern v_data_abrt
+.extern v_reserved
 .extern v_irq
+.extern v_fiq
 
 .section .init
 
@@ -80,27 +86,6 @@ done_bss2:
 
 .pool
 
-v_undf:
-	b v_undf
-
-v_swi:
-	b v_swi
-
-v_instr_abrt:
-	b v_instr_abrt
-
-v_data_abrt:
-	b v_data_abrt
-
-v_reserved:
-	b v_reserved
-
-#v_irq:
-#	b v_irq
-
-v_fiq:
-	b v_fiq
-
 debug_output:
 	@ load address of port
 	mov	r3, #0xd800000