WebSVN – HelenOS – Diff – /branches/dynload/kernel/arch/arm32/src/exception.c

-    /*
+/*
  * Copyright (c) 2007 Petr Stepan
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  */
 #include <arch/exception.h>
 #include "aux_print/printf.h"
 #include <arch/memstr.h>
+#include <arch/regutils.h>
+#include <interrupt.h>
 #define PREFETCH_OFFSET     0x8
 #define BRANCH_OPCODE       0xea000000
+#define LDR_OPCODE      0xe59ff000
 #define VALID_BRANCH_MASK   0xff000000
+#define EXC_VECTORS_SIZE    0x20
+#define EXC_VECTORS     0x8
+/* GXEmul interrupt controller macros
-/** Updates specified exception vector to jump to given handler.
+TODO might go to drivers/ together with servicing functions
 */
-static void install_handler (unsigned* handler, unsigned* vector) {
+/* IRQ Controller device is added in a special premium gxemul
+ * edition at www.ms.mff.cuni.cz/~stepp3am/mygxemul-0.4.4.1.tar.gz
+ * :)
+ */
+#define IRQ_CONTROLLER_CAUSE    0x0000000016000000
+#define IRQ_CONTROLLER_MAX_IRQ  8
+/* IRQs */
+#define CONSOLE_IRQ     2
-    volatile unsigned vec;
+#define TIMER_IRQ       4
-    /* calculate relative distance */
+#define SAVE_REGS_TO_STACK          \
-    vec = ((unsigned)handler - (unsigned)vector - PREFETCH_OFFSET);
+    asm("stmfd sp!, {r0-r12, sp, lr}");     \
+    asm("mrs r14, spsr");           \
+    asm("stmfd sp!, {r14}");
+#define CALL_EXC_DISPATCH(exception)        \
+    asm("mov r0, %0" : : "i" (exception));  \
-    /* word offset */
+    asm("mov r1, sp");          \
+    asm("bl exc_dispatch");
+/**Loads registers from the stack and resets SPSR before exitting exception
-    vec >>= 2;
+ * handler.
+ */
+#define LOAD_REGS_FROM_STACK            \
+    asm("ldmfd sp!, {r14}");        \
+    asm("msr spsr, r14");           \
+    asm("ldmfd sp!, {r0-r12, sp, pc}^");
+/** General exception handler.
-    /* check if haven't jumped beyond 32 MB */
+ *  Stores registers, dispatches the exception,
+ *  and finally restores registers and returns from exception processing.
+ */
+#define PROCESS_EXCEPTION(exception)        \
+    SAVE_REGS_TO_STACK          \
-    if ((vec & VALID_BRANCH_MASK) != 0) {
+    CALL_EXC_DISPATCH(exception)        \
+    LOAD_REGS_FROM_STACK
-        /*panic("exception handler beyond 32MB.");*/
+/** Updates specified exception vector to jump to given handler.
+ * Addresses of handlers are stored in memory following exception vectors.
-        return;
+ */
+static void install_handler (unsigned handler_addr, unsigned* vector)
+{
+    /* relative address (related to exc. vector) of the word
+     * where handler's address is stored
-    }
+    */
+    volatile uint32_t handler_address_ptr = EXC_VECTORS_SIZE - PREFETCH_OFFSET;
-    /* make it branch instruction */
+    /* make it LDR instruction and store at exception vector */
-    vec |= BRANCH_OPCODE;
+    *vector = handler_address_ptr | LDR_OPCODE;
-    *vector = vec;
+    /* store handler's address */
+    *(vector + EXC_VECTORS) = handler_addr;
+}
+static void reset_exception_entry()
+{
+    PROCESS_EXCEPTION(EXC_RESET);
+}
+/** Low-level Software Interrupt Exception handler */
+static void swi_exception_entry()
+{
+    PROCESS_EXCEPTION(EXC_SWI);
+}
-    aux_printf("installed  handler to %p, to vector %p\n.", handler, vector);
+/** Low-level Undefined Instruction Exception handler */
+static void undef_instr_exception_entry()
+{
+    PROCESS_EXCEPTION(EXC_UNDEF_INSTR);
+}
+/** Low-level Fast Interrupt Exception handler */
+static void fiq_exception_entry()
+{
+    PROCESS_EXCEPTION(EXC_FIQ);
+}
+/** Low-level Prefetch Abort Exception handler */
+static void prefetch_abort_exception_entry()
+{
+    asm("sub lr, lr, #4");
+    PROCESS_EXCEPTION(EXC_PREFETCH_ABORT);
+}
-/* TODO add other exception handlers */
+/** Low-level Data Abort Exception handler */
-static void dummy_exception(){
+static void data_abort_exception_entry()
+{
-    asm("bkpt");
+    asm("sub lr, lr, #8");
+    PROCESS_EXCEPTION(EXC_DATA_ABORT);
+}
-/** IRQ Exception handler */
+/** Low-level Interrupt Exception handler */
-static void irq_exception(){
+static void irq_exception_entry()
+{
-    asm("bkpt");
+    asm("sub lr, lr, #4");
+    PROCESS_EXCEPTION(EXC_IRQ);
+}
+/** Interrupt Exception handler.
+ * Determines the sources of interrupt, and calls their handlers.
+ */
+static void irq_exception(int exc_no, istate_t* istate)
+{
+    /* TODO this will call interrupt dispatching routine
+     *
+     */
+    uint32_t sources = *(uint32_t*) IRQ_CONTROLLER_CAUSE;
+    int i = 0;
+    int noirq = 1;
+    for (; i < IRQ_CONTROLLER_MAX_IRQ; i++) {
+        if (sources & (1 << i)) {
+            noirq = 0;
+            if (i == CONSOLE_IRQ) {
+                char readchar = *(char*)0x10000000;
+                if (readchar == 0) {
+                    aux_puts("?");
+                }
+                else {
+                    aux_printf("%c", readchar);
+                }
+            }
+            else if (i == TIMER_IRQ) {
+                aux_printf("\n.\n");
+                /* acknowledge  */
+                *(uint32_t*)0x15000110 = 0;
+            }
+        }
+    }
+    if (noirq)
+        aux_puts("IRQ exception without source\n");
+}
 /** Fills exception vectors with appropriate exception handlers.
 */
-void install_exception_handlers(void) {
+void install_exception_handlers(void)
+{
-    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_RESET_VEC);
+    install_handler((unsigned)reset_exception_entry,
+             (unsigned*)EXC_RESET_VEC);
-    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_UNDEF_INSTR_VEC);
+    install_handler((unsigned)undef_instr_exception_entry,
+             (unsigned*)EXC_UNDEF_INSTR_VEC);
-    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_SWI_VEC);
+    install_handler((unsigned)swi_exception_entry,
+             (unsigned*)EXC_SWI_VEC);
-    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_PREFETCH_ABORT_VEC);
+    install_handler((unsigned)prefetch_abort_exception_entry,
+             (unsigned*)EXC_PREFETCH_ABORT_VEC);
-    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_DATA_ABORT_VEC);
+    install_handler((unsigned)data_abort_exception_entry,
+             (unsigned*)EXC_DATA_ABORT_VEC);
-    install_handler((unsigned*)irq_exception,   (unsigned*)EXC_IRQ_VEC);
+    install_handler((unsigned)irq_exception_entry,
+             (unsigned*)EXC_IRQ_VEC);
-    install_handler((unsigned*)dummy_exception, (unsigned*)EXC_FIQ_VEC);
+    install_handler((unsigned)fiq_exception_entry,
+             (unsigned*)EXC_FIQ_VEC);
+}
 /** Registers exceptions and their handlers to kernel exception dispatcher. */
-void exception_init(void){
+void exception_init(void)
+{
+    exc_register(EXC_IRQ, "interrupt", (iroutine) irq_exception);
-    /* TODO */
+    /* TODO add next */
+}
+/* TODO change soon, temporary hack. */
+void setup_exception_stacks()
+{
+    /* switch to particular mode and set "sp" there */
+    uint32_t cspr = current_status_reg_read();
+    current_status_reg_control_write(
+            (cspr & ~STATUS_REG_MODE_MASK) | IRQ_MODE
+    );
+    asm("ldr sp, =irq_stack");
+    current_status_reg_control_write( cspr);
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)/branches/dynload/kernel/arch/arm32/src/exception.c @ 4346 – Rev 2179 → 2235