Looking function mips_timer_interrupt() (which is the normal timer
interrupt when PM is not enabled) I noticed that it has called from
file «arch/mips/au1000/common/int-handler.S» as follow:
...
.text
.set macro
.set noat
.align 5
NESTED(au1000_IRQ, PT_SIZE, sp)
SAVE_ALL
CLI # Important: mark KERNEL mode !
mfc0 t0,CP0_CAUSE # get pending interrupts
mfc0 t1,CP0_STATUS # get enabled interrupts
and t0,t1 # isolate allowed ones
andi t0,0xff00 # isolate pending bits
beqz t0, 3f # spurious interrupt
andi a0, t0, CAUSEF_IP7
beq a0, zero, 1f
move a0, sp
jal mips_timer_interrupt
j ret_from_irq
...
Looking at «CLI» implementation into «include/asm/stackframe.h»:
/*
* Move to kernel mode and disable interrupts.
* Set cp0 enable bit as sign that we're running on the kernel stack
*/
.macro CLI
mfc0 t0, CP0_STATUS
li t1, ST0_CU0 | 0x1f
or t0, t1
xori t0, 0x1f
mtc0 t0, CP0_STATUS
irq_disable_hazard
.endm
I see that the CLI macro ensures that mips_timer_interrupt() will be
executed into «kernel mode».
What do you think about that? Can it cause the error «Break
instruction in kernel code in arch/mips/kernel/traps.c::do_bp, line
629[#1]:»?
If so, can someone help me in fixing such bug? I'm not a MIPS assembly
master! ;-p
Ciao,
Rodolfo
--
GNU/Linux Solutions e-mail: giometti@xxxxxxxx
Linux Device Driver giometti@xxxxxxxxxxxx
Embedded Systems home page: giometti.enneenne.com
UNIX programming phone: +39 349 2432127
Attachment:
signature.asc
Description: Digital signature
