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

 #include <arch/memstr.h>
 #include <arch/regutils.h>
 #include <interrupt.h>
 #include <arch/drivers/gxemul.h>
 #include <arch/mm/page_fault.h>
+#include <print.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
+extern uintptr_t supervisor_sp;
+extern uintptr_t exc_stack;
+inline static void setup_stack_and_save_regs()
+{
+asm volatile(   "ldr r13, =exc_stack        \n\
+    stmfd r13!, {r0}            \n\
+    mrs r0, spsr                \n\
+    and r0, r0, #0x1f           \n\
+    cmp r0, #0x10               \n\
+    bne 1f                  \n\
+                        \n\
+    @prev mode was usermode         \n\
+    ldmfd r13!, {r0}            \n\
+    ldr r13, =supervisor_sp         \n\
+    stmfd r13!, {r0-r12, r13, lr}       \n\
+    stmfd r13!, {r13, lr}^          \n\
+    mrs r0, spsr                \n\
+    stmfd r13!, {r0}            \n\
+    b 2f                    \n\
+                        \n\
+    @prev mode was not usermode     \n\
+:                      \n\
+    stmfd r13!, {r1, r2, r3}        \n\
+    mrs r1, cpsr                \n\
+    mov r2, lr              \n\
+    bic r1, r1, #0x1f           \n\
+    orr r1, r1, r0              \n\
+    mrs r0, cpsr                \n\
+    msr cpsr_c, r1              \n\
+                        \n\
+    mov r3, r13             \n\
+    stmfd r13!, {r2}            \n\
+    stmfd r13!, {r3}            \n\
+    stmfd r13!, {r4-r12}            \n\
+    mov r2, lr              \n\
+    mov r1, r13             \n\
+    msr cpsr_c, r0              \n\
+                        \n\
+    ldmfd r13!, {r4, r5, r6, r7}        \n\
+    stmfd r1!, {r4, r5, r6}         \n\
+    stmfd r1!, {r7}             \n\
+    stmfd r1!, {r2}             \n\
+    stmfd r1!, {r3}             \n\
+    mrs r0, spsr                \n\
+    stmfd r1!, {r0}             \n\
+    mov r13, r1             \n\
+:"
+);
+}
+inline static void load_regs()
+{
+asm volatile(   "ldmfd r13!, {r0}       \n\
+    msr spsr, r0                \n\
+    and r0, r0, #0x1f           \n\
+    cmp r0, #0x10               \n\
+    bne 3f                  \n\
+                        \n\
+    @return to user mode            \n\
+    ldmfd r13!, {r13, lr}^          \n\
+    b 4f                    \n\
+                        \n\
+    @return to non-user mode        \n\
+:                      \n\
+    ldmfd r13!, {r1, r2}            \n\
+    mrs r3, cpsr                \n\
+    bic r3, r3, #0x1f           \n\
+    orr r3, r3, r0              \n\
+    mrs r0, cpsr                \n\
+    msr cpsr_c, r3              \n\
+                        \n\
+    mov r13, r1             \n\
+    mov lr, r2              \n\
+    msr cpsr_c, r0              \n\
+                        \n\
+    @actual return              \n\
+:                      \n\
+    ldmfd r13!, {r0-r12, r13, pc}^"
+);
+}
 #define SAVE_REGS_TO_STACK          \
-    asm("stmfd sp!, {r0-r12, sp, lr}");     \
+    asm("stmfd r13!, {r0-r12, r13, lr}");   \
     asm("mrs r14, spsr");           \
-    asm("stmfd sp!, {r14}");
+    asm("stmfd r13!, {r14}");
 #define CALL_EXC_DISPATCH(exception)        \
     asm("mov r0, %0" : : "i" (exception));  \
-    asm("mov r1, sp");          \
+    asm("mov r1, r13");         \
     asm("bl exc_dispatch");
 /**Loads registers from the stack and resets SPSR before exitting exception
  * handler.
  */
 #define LOAD_REGS_FROM_STACK            \
-    asm("ldmfd sp!, {r14}");        \
+    asm("ldmfd r13!, {r14}");       \
     asm("msr spsr, r14");           \
-    asm("ldmfd sp!, {r0-r12, sp, pc}^");
+    asm("ldmfd r13!, {r0-r12, r13, pc}^");
 /** General exception handler.
  *  Stores registers, dispatches the exception,
  *  and finally restores registers and returns from exception processing.
  */
 #define PROCESS_EXCEPTION(exception)        \
-    SAVE_REGS_TO_STACK          \
+    setup_stack_and_save_regs();        \
     CALL_EXC_DISPATCH(exception)        \
+    load_regs();
+/* #define PROCESS_EXCEPTION(exception)     \
+    SAVE_REGS_TO_STACK      \
+    CALL_EXC_DISPATCH(exception)        \
-    LOAD_REGS_FROM_STACK
+    LOAD_REGS_FROM_STACK*/
 /** Updates specified exception vector to jump to given handler.
  * Addresses of handlers are stored in memory following exception vectors.
  */
 static void install_handler (unsigned handler_addr, unsigned* vector)
     /* make it LDR instruction and store at exception vector */
     *vector = handler_address_ptr | LDR_OPCODE;
     /* store handler's address */
     *(vector + EXC_VECTORS) = handler_addr;
+}
 static void reset_exception_entry()
+{
     PROCESS_EXCEPTION(EXC_RESET);
+}
 /** Low-level Interrupt Exception handler */
 static void irq_exception_entry()
+{
     asm("sub lr, lr, #4");
+//  SAVE_REGS_TO_STACK
+//  CALL_EXC_DISPATCH(EXC_IRQ)
+//  LOAD_REGS_FROM_STACK;
     PROCESS_EXCEPTION(EXC_IRQ);
+}
+// static void prefetch_abort_exception(int exc_no, istate_t* istate)
+// {
+//  dputs("(PREFETCH|DATA) ABORT exception caught, not processed.\n");
+// }
+static void swi_exception(int exc_no, istate_t* istate)
+{
+    dprintf("\nIstate dump:\n");
+    dprintf("    r0:%X    r1:%X    r2:%X    r3:%X\n", istate->r0,  istate->r1, istate->r2,  istate->r3);
+    dprintf("    r4:%X    r5:%X    r6:%X    r7:%X\n", istate->r4,  istate->r5, istate->r6,  istate->r7);
+    dprintf("    r8:%X    r9:%X   r10:%X     r11:%X\n", istate->r8,  istate->r9, istate->r10, istate->r11);
+    dprintf("      r12:%X    r13:%X    lr:%X  spsr:%X\n", istate->r12, istate->sp, istate->lr,  istate->spsr);
+    dprintf("   prev_lr:%X    prev_sp:%X\n", istate->prev_lr, istate->prev_sp);
+}
 /** Interrupt Exception handler.
  * Determines the sources of interrupt, and calls their handlers.
  */
 static void irq_exception(int exc_no, istate_t* istate)
              (unsigned*)EXC_PREFETCH_ABORT_VEC);
     install_handler((unsigned)data_abort_exception_entry,
              (unsigned*)EXC_DATA_ABORT_VEC);
     install_handler((unsigned)irq_exception_entry,
              (unsigned*)EXC_IRQ_VEC);
     install_handler((unsigned)fiq_exception_entry,
              (unsigned*)EXC_FIQ_VEC);
+}
+#ifdef HIGH_EXCEPTION_VECTORS
 /** Activates using high exception vectors addresses. */
  static void high_vectors()
+{
     uint32_t control_reg;
     //switch on the high vectors bit
     control_reg |= CP15_R1_HIGH_VECTORS_BIT;
     asm volatile( "mcr p15, 0, %0, c1, c1" : : "r" (control_reg));
+}
+#endif
 /** Initializes exception handling.
+ *
  * Installs low-level exception handlers and then registers
  * exceptions and their handlers to kernel exception dispatcher.
 void exception_init(void)
+{
 #ifdef HIGH_EXCEPTION_VECTORS
     high_vectors();
 #endif
     install_exception_handlers();
     exc_register(EXC_IRQ, "interrupt", (iroutine) irq_exception);
     exc_register(EXC_PREFETCH_ABORT, "prefetch abort", (iroutine) prefetch_abort);
     exc_register(EXC_DATA_ABORT, "data abort", (iroutine) data_abort);
+    exc_register(EXC_SWI, "software interrupt", (iroutine) swi_exception);
     /* TODO add next */
+}
-/* TODO change soon, temporary hack. */
+/** Sets stack pointers in all supported exception modes.
+ *
+ * @param stack_ptr stack pointer
+ */
 void setup_exception_stacks()
+{
-    /* switch to particular mode and set "sp" there */
+        /* switch to particular mode and set "r13" there */
-    uint32_t cspr = current_status_reg_read();
+        uint32_t cspr = current_status_reg_read();
-    /* IRQ stack */
+        /* IRQ stack */
-    current_status_reg_control_write(
+        current_status_reg_control_write(
-            (cspr & ~STATUS_REG_MODE_MASK) | IRQ_MODE
+                        (cspr & ~STATUS_REG_MODE_MASK) | IRQ_MODE
-    );
+        );
-    asm("ldr sp, =irq_stack");
+        asm("ldr r13, =exc_stack");
-    /* abort stack */
+        /* abort stack */
-    current_status_reg_control_write(
+        current_status_reg_control_write(
-            (cspr & ~STATUS_REG_MODE_MASK) | ABORT_MODE
+                        (cspr & ~STATUS_REG_MODE_MASK) | ABORT_MODE
-    );
+        );
-    asm("ldr sp, =abort_stack");
+        asm("ldr r13, =exc_stack");
-    /* TODO if you want to test other exceptions than IRQ,
+        /* TODO if you want to test other exceptions than IRQ,
-    make stack analogous to irq_stack (in start.S),
+        make stack analogous to irq_stack (in start.S),
-    and then set stack pointer here */
+        and then set stack pointer here */
-    current_status_reg_control_write( cspr);
+        current_status_reg_control_write( cspr);
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)/trunk/kernel/arch/arm32/src/exception.c @ 2465 – Rev 2282 → 2284