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extern uintptr_t supervisor_sp;
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extern uintptr_t supervisor_sp;
57 
extern uintptr_t exc_stack;
 57 
extern uintptr_t exc_stack;
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 58 
 
- 
 
 59 
/** Switches to kernel stack and saves all registers there.
59 
 
 60 
 *
- 
 
 61 
 * Temporary exception stack is used to save a few registers
- 
 
 62 
 * before stack switch takes place.
- 
 
 63 
 */
60 
inline static void setup_stack_and_save_regs()
 64 
inline static void setup_stack_and_save_regs()
61 
{
 65 
{
62 
/*
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 - 
 
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str r0, =exc_stack
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str r1, =exc_stack + 4
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66 
mrs r0, cpsr
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mrs r1, spsr
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and r0, r0, #0x1f
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and r1, r1, #0x1f
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cmp r0, r1
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be 3f
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@different exception mode => preserve sp
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ldr r1, [=exc_stack + 4]
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ldr r0, [=exc_stack]
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3:
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mrs r0, spsr
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stmfd sp!, {r0, sp, lr}
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*/
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asm volatile("ldr r13, =exc_stack       \n\
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asm volatile("ldr r13, =exc_stack       \n\
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    stmfd r13!, {r0}            \n\
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    stmfd r13!, {r0}            \n\
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    mrs r0, spsr                \n\
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    mrs r0, spsr                \n\
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    and r0, r0, #0x1f           \n\
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    and r0, r0, #0x1f           \n\
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    cmp r0, #0x10               \n\
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    cmp r0, #0x10               \n\
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    mov r13, r1             \n\
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    mov r13, r1             \n\
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2:"
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2:"
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);
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);
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}
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}
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- 
 
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/** Returns from exception mode.
- 
 
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 *
- 
 
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 * Previously saved state of registers (including control register)
- 
 
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 * is restored from the stack.
131 
 
 120 
 */
132 
inline static void load_regs()
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inline static void load_regs()
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{
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{
134 
asm volatile(   "ldmfd r13!, {r0}       \n\
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asm volatile(   "ldmfd r13!, {r0}       \n\
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    msr spsr, r0                \n\
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    msr spsr, r0                \n\
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    and r0, r0, #0x1f           \n\
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    and r0, r0, #0x1f           \n\
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    @actual return              \n\
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    @actual return              \n\
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4:  ldmfd r13, {r0-r12, pc}^"
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4:  ldmfd r13, {r0-r12, pc}^"
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);
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);
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}
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}
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 150 
 
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/*#define SAVE_REGS_TO_STACK            \
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165 
    asm("stmfd r13!, {r0-r12, r13, lr}");   \
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/** Calls exception dispatch routine. */
166 
    asm("mrs r14, spsr");           \
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    asm("stmfd r13!, {r14}");
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*/
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#define CALL_EXC_DISPATCH(exception)        \
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#define CALL_EXC_DISPATCH(exception)        \
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    asm("mov r0, %0" : : "i" (exception));  \
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    asm("mov r0, %0" : : "i" (exception));  \
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    asm("mov r1, r13");         \
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    asm("mov r1, r13");         \
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    asm("bl exc_dispatch");    
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    asm("bl exc_dispatch");    
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 - 
 
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/**Loads registers from the stack and resets SPSR before exitting exception
 - 
 
178 
 * handler.
 - 
 
179 
 
 - 
 
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#define LOAD_REGS_FROM_STACK            \
 - 
 
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    asm("ldmfd r13!, {r14}");       \
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182 
    asm("msr spsr, r14");           \
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183 
    asm("ldmfd r13!, {r0-r12, r13, pc}^");
 - 
 
184 
 */
 - 
 
185 
 
 - 
 
186 
   
 157 
   
187 
/** General exception handler.
 158 
/** General exception handler.
- 
 
 159 
 *
188 
 *  Stores registers, dispatches the exception,
 160 
 *  Stores registers, dispatches the exception,
189 
 *  and finally restores registers and returns from exception processing.
 161 
 *  and finally restores registers and returns from exception processing.
190 
 *
 162 
 *
191 
 *  @param exception Exception number.
 163 
 *  @param exception Exception number.
192 
 */
 164 
 */
193 
#define PROCESS_EXCEPTION(exception)        \
 165 
#define PROCESS_EXCEPTION(exception)        \
194 
    setup_stack_and_save_regs();        \
 166 
    setup_stack_and_save_regs();        \
195 
    CALL_EXC_DISPATCH(exception)        \
 167 
    CALL_EXC_DISPATCH(exception)        \
196 
    load_regs();
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    load_regs();
197 
 
 169 
 
198 
/* #define PROCESS_EXCEPTION(exception)     \
 - 
 
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    SAVE_REGS_TO_STACK      \
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200 
    CALL_EXC_DISPATCH(exception)        \
 - 
 
201 
    LOAD_REGS_FROM_STACK*/
 - 
 
202 
 
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203 
 
 170 
 
204 
/** Updates specified exception vector to jump to given handler.
 171 
/** Updates specified exception vector to jump to given handler.
- 
 
 172 
 *
205 
 *  Addresses of handlers are stored in memory following exception vectors.
 173 
 *  Addresses of handlers are stored in memory following exception vectors.
206 
 */
 174 
 */
207 
static void install_handler (unsigned handler_addr, unsigned* vector)
 175 
static void install_handler (unsigned handler_addr, unsigned* vector)
208 
{
 176 
{
209 
    /* relative address (related to exc. vector) of the word
 177 
    /* relative address (related to exc. vector) of the word
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    asm("sub lr, lr, #8");
 230 
    asm("sub lr, lr, #8");
263 
    PROCESS_EXCEPTION(EXC_DATA_ABORT);
 231 
    PROCESS_EXCEPTION(EXC_DATA_ABORT);
264 
}
 232 
}
265 
 
 233 
 
266 
 
 234 
 
267 
/** Low-level Interrupt Exception handler. */
 235 
/** Low-level Interrupt Exception handler.
- 
 
 236 
 *
- 
 
 237 
 * CPU is switched to Undefined mode before further interrupt processing
- 
 
 238 
 * because of possible occurence of nested interrupt exception, which
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 * would overwrite (and thus spoil) stack pointer.
- 
 
 240 
 */
268 
static void irq_exception_entry()
 241 
static void irq_exception_entry()
269 
{
 242 
{
270 
    asm("sub lr, lr, #4");
 243 
    asm("sub lr, lr, #4");
271 
    setup_stack_and_save_regs();
 244 
    setup_stack_and_save_regs();
272 
 
 245 
 
273 
    /* switch to Undefined mode */
 246 
    /* switch to Undefined mode */
274 
    asm("stmfd sp!, {r0-r3}");
 247 
    asm("stmfd sp!, {r0-r3}");
275 
    asm("mov r1, sp");
 248 
    asm("mov r1, sp");
276 
    asm("mov r2, lr");
 249 
    asm("mov r2, lr");
277 
//  asm("mrs r3, spsr");
 - 
 
278 
    asm("mrs r0, cpsr");
 250 
    asm("mrs r0, cpsr");
279 
    asm("bic r0, r0, #0x1f");
 251 
    asm("bic r0, r0, #0x1f");
280 
    asm("orr r0, r0, #0x1b");
 252 
    asm("orr r0, r0, #0x1b");
281 
    asm("msr cpsr_c, r0");
 253 
    asm("msr cpsr_c, r0");
282 
    asm("mov sp, r1");
 254 
    asm("mov sp, r1");
283 
    asm("mov lr, r2");
 255 
    asm("mov lr, r2");
284 
//  asm("msr spsr, r3");
 - 
 
285 
    asm("ldmfd sp!, {r0-r3}");
 256 
    asm("ldmfd sp!, {r0-r3}");
286 
 
 257 
 
287 
    CALL_EXC_DISPATCH(EXC_IRQ)
 258 
    CALL_EXC_DISPATCH(EXC_IRQ)
288 
 
 259 
 
289 
    load_regs();
 260 
    load_regs();
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377 
    exc_register(EXC_IRQ, "interrupt", (iroutine) irq_exception);
 348 
    exc_register(EXC_IRQ, "interrupt", (iroutine) irq_exception);
378 
    exc_register(EXC_PREFETCH_ABORT, "prefetch abort", (iroutine) prefetch_abort);
 349 
    exc_register(EXC_PREFETCH_ABORT, "prefetch abort", (iroutine) prefetch_abort);
379 
    exc_register(EXC_DATA_ABORT, "data abort", (iroutine) data_abort);
 350 
    exc_register(EXC_DATA_ABORT, "data abort", (iroutine) data_abort);
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    exc_register(EXC_SWI, "software interrupt", (iroutine) swi_exception);
 351 
    exc_register(EXC_SWI, "software interrupt", (iroutine) swi_exception);
381 
    /* TODO add next */
 - 
 
382 
}
 - 
 
383 
 
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384 
 
 - 
 
385 
/** Sets stack pointers in all supported exception modes. */
 - 
 
386 
void setup_exception_stacks()
 - 
 
387 
{
 - 
 
388 
        /* switch to particular mode and set "r13" there */
 - 
 
389 
 
 - 
 
390 
        uint32_t cspr = current_status_reg_read();
 - 
 
391 
 
 - 
 
392 
        /* IRQ stack */
 - 
 
393 
        current_status_reg_control_write(
 - 
 
394 
                        (cspr & ~STATUS_REG_MODE_MASK) | IRQ_MODE
 - 
 
395 
        );
 - 
 
396 
        asm("ldr r13, =exc_stack");
 - 
 
397 
 
 - 
 
398 
        /* abort stack */
 - 
 
399 
        current_status_reg_control_write(
 - 
 
400 
                        (cspr & ~STATUS_REG_MODE_MASK) | ABORT_MODE
 - 
 
401 
        );
 - 
 
402 
        asm("ldr r13, =exc_stack");
 - 
 
403 
 
 - 
 
404 
        /* TODO if you want to test other exceptions than IRQ,
 - 
 
405 
        make stack analogous to irq_stack (in start.S),
 - 
 
406 
        and then set stack pointer here */
 - 
 
407 
 
 - 
 
408 
        current_status_reg_control_write(cspr);
 - 
 
409 
}
 352 
}
410 
 
 353 
 
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412 
/** Prints #istate_t structure content.
 355 
/** Prints #istate_t structure content.
413 
 *
 356 
 *