/* irq.c
*
* This file contains the implementation of the function described in irq.h
*
* Copyright (C) 1998 valette@crf.canon.fr
*
* COPYRIGHT (c) 1989-2011.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#include <rtems/asm.h>
#include <rtems/system.h>
#include <bspopts.h>
#include <bsp/irq_asm.h>
#include <rtems/score/cpu.h>
#include <rtems/score/percpu.h>
#ifndef CPU_STACK_ALIGNMENT
#error "Missing header? CPU_STACK_ALIGNMENT is not defined here"
#endif
/* Stack frame we use for intermediate storage */
#define ARG_OFF 0
#define MSK_OFF 4
#define EBX_OFF 8 /* ebx */
#define EBP_OFF 12 /* code restoring ebp/esp relies on */
#define ESP_OFF 16 /* esp being on top of ebp! */
#ifdef __SSE__
/* need to be on 16 byte boundary for SSE, add 12 to do that */
#define FRM_SIZ (20+12+512)
#define SSE_OFF 32
#else
#define FRM_SIZ 20
#endif
BEGIN_CODE
SYM (_ISR_Handler):
/*
* Before this was point is reached the vectors unique
* entry point did the following:
*
* 1. saved scratch registers registers eax edx ecx"
* 2. put the vector number in ecx.
*
* BEGINNING OF ESTABLISH SEGMENTS
*
* WARNING: If an interrupt can occur when the segments are
* not correct, then this is where we should establish
* the segments. In addition to establishing the
* segments, it may be necessary to establish a stack
* in the current data area on the outermost interrupt.
*
* NOTE: If the previous values of the segment registers are
* pushed, do not forget to adjust SAVED_REGS.
*
* NOTE: Make sure the exit code which restores these
* when this type of code is needed.
*/
/***** ESTABLISH SEGMENTS CODE GOES HERE ******/
/*
* END OF ESTABLISH SEGMENTS
*/
/*
* Establish an aligned stack frame
* original sp
* saved ebx
* saved ebp
* saved irq mask
* vector arg to C_dispatch_isr <- aligned SP
*/
movl esp, eax
subl $FRM_SIZ, esp
andl $ - CPU_STACK_ALIGNMENT, esp
movl ebx, EBX_OFF(esp)
movl eax, ESP_OFF(esp)
movl ebp, EBP_OFF(esp)
#ifdef __SSE__
/* NOTE: SSE only is supported if the BSP enables fxsave/fxrstor
* to save/restore SSE context! This is so far only implemented
* for pc386!.
*/
/* We save SSE here (on the task stack) because we possibly
* call other C-code (besides the ISR, namely _Thread_Dispatch())
*/
/* don't wait here; a possible exception condition will eventually be
* detected when the task resumes control and executes a FP instruction
fwait
*/
fxsave SSE_OFF(esp)
fninit /* clean-slate FPU */
movl $0x1f80, ARG_OFF(esp) /* use ARG_OFF as scratch space */
ldmxcsr ARG_OFF(esp) /* clean-slate MXCSR */
#endif
/* Do not disable any 8259 interrupts if this isn't from one */
cmp ecx, 16 /* is this a PIC IRQ? */
jge .check_stack_switch
/*
* acknowledge the interrupt
*/
movw SYM (i8259s_cache), ax /* save current i8259 interrupt mask */
movl eax, MSK_OFF(esp) /* save in stack frame */
/*
* compute the new PIC mask:
*
* <new mask> = <old mask> | irq_mask_or_tbl[<intr number aka ecx>]
*/
movw SYM (irq_mask_or_tbl) (,ecx,2), dx
orw dx, ax
/*
* Install new computed value on the i8259 and update cache
* accordingly
*/
movw ax, SYM (i8259s_cache)
outb $PIC_MASTER_IMR_IO_PORT
movb ah, al
outb $PIC_SLAVE_IMR_IO_PORT
movb $PIC_EOI, al
cmpl $7, ecx
jbe .master
outb $PIC_SLAVE_COMMAND_IO_PORT
.master:
outb $PIC_MASTER_COMMAND_IO_PORT
/*
* Now switch stacks if necessary
*/
PUBLIC (ISR_STOP)
ISR_STOP:
.check_stack_switch:
movl esp, ebp /* ebp = previous stack pointer */
#ifdef RTEMS_SMP
call SYM(_CPU_SMP_Get_current_processor)
sall $PER_CPU_CONTROL_SIZE_LOG2, eax
addl $SYM(_Per_CPU_Information), eax
movl eax, ebx
#else
movl $SYM(_Per_CPU_Information), ebx
#endif
/* is this the outermost interrupt? */
cmpl $0, PER_CPU_ISR_NEST_LEVEL(ebx)
jne nested /* No, then continue */
movl PER_CPU_INTERRUPT_STACK_HIGH(ebx), esp
/*
* We want to insure that the old stack pointer is in ebp
* By saving it on every interrupt, all we have to do is
* movl ebp->esp near the end of every interrupt.
*/
nested:
incl PER_CPU_ISR_NEST_LEVEL(ebx) /* one nest level deeper */
incl PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL(ebx) /* disable
multitasking */
/*
* GCC versions starting with 4.3 no longer place the cld
* instruction before string operations. We need to ensure
* it is set correctly for ISR handlers.
*/
cld
/*
* re-enable interrupts at processor level as the current
* interrupt source is now masked via i8259
*/
sti
/*
* ECX is preloaded with the vector number; store as arg
* on top of stack. Note that _CPU_Interrupt_stack_high
* was adjusted in _CPU_Interrupt_stack_setup() (score/rtems/cpu.h)
* to make sure there is space.
*/
movl ecx, ARG_OFF(esp) /* store vector arg in stack */
call C_dispatch_isr
/*
* disable interrupts_again
*/
cli
movl ARG_OFF(esp), ecx /* grab vector arg from stack */
/*
* Restore stack. This moves back to the task stack
* when all interrupts are unnested.
*/
movl ebp, esp
/*
* restore the original i8259 masks
*/
/* Do not touch 8259 interrupts if this isn't from one */
cmp ecx, 16 /* is this a PIC IRQ? */
jge .dont_restore_i8259
movl MSK_OFF(esp), eax
movw ax, SYM (i8259s_cache)
outb $PIC_MASTER_IMR_IO_PORT
movb ah, al
outb $PIC_SLAVE_IMR_IO_PORT
.dont_restore_i8259:
decl PER_CPU_ISR_NEST_LEVEL(ebx) /* one less ISR nest level */
/* If interrupts are nested, */
/* then dispatching is disabled */
decl PER_CPU_THREAD_DISPATCH_DISABLE_LEVEL(ebx)
/* unnest multitasking */
/* Is dispatch disabled */
jne .exit /* Yes, then exit */
cmpb $0, PER_CPU_DISPATCH_NEEDED(ebx)
/* Is task switch necessary? */
jne .schedule /* Yes, then call the scheduler */
jmp .exit /* No, exit */
.schedule:
/*
* the scratch registers have already been saved and we are already
* back on the thread system stack. So we can call _Thread_Dispatch
* directly
*/
call _Thread_Dispatch
/*
* fall through exit to restore complete contex (scratch registers
* eip, CS, Flags).
*/
.exit:
#ifdef __SSE__
fwait
fxrstor SSE_OFF(esp)
#endif
/* restore ebx, ebp and original esp */
addl $EBX_OFF, esp
popl ebx
popl ebp
popl esp
/*
* BEGINNING OF DE-ESTABLISH SEGMENTS
*
* NOTE: Make sure there is code here if code is added to
* load the segment registers.
*
*/
/******* DE-ESTABLISH SEGMENTS CODE GOES HERE ********/
/*
* END OF DE-ESTABLISH SEGMENTS
*/
popl edx
popl ecx
popl eax
iret
#define DISTINCT_INTERRUPT_ENTRY(_vector) \
.p2align 4 ; \
PUBLIC (rtems_irq_prologue_ ## _vector ) ; \
SYM (rtems_irq_prologue_ ## _vector ): \
pushl eax ; \
pushl ecx ; \
pushl edx ; \
movl $ _vector, ecx ; \
jmp SYM (_ISR_Handler) ;
DISTINCT_INTERRUPT_ENTRY(0)
DISTINCT_INTERRUPT_ENTRY(1)
DISTINCT_INTERRUPT_ENTRY(2)
DISTINCT_INTERRUPT_ENTRY(3)
DISTINCT_INTERRUPT_ENTRY(4)
DISTINCT_INTERRUPT_ENTRY(5)
DISTINCT_INTERRUPT_ENTRY(6)
DISTINCT_INTERRUPT_ENTRY(7)
DISTINCT_INTERRUPT_ENTRY(8)
DISTINCT_INTERRUPT_ENTRY(9)
DISTINCT_INTERRUPT_ENTRY(10)
DISTINCT_INTERRUPT_ENTRY(11)
DISTINCT_INTERRUPT_ENTRY(12)
DISTINCT_INTERRUPT_ENTRY(13)
DISTINCT_INTERRUPT_ENTRY(14)
DISTINCT_INTERRUPT_ENTRY(15)
DISTINCT_INTERRUPT_ENTRY(16)
/*
* routine used to initialize the IDT by default
*/
PUBLIC (default_raw_idt_handler)
PUBLIC (raw_idt_notify)
SYM (default_raw_idt_handler):
pusha
cld
mov esp, ebp
andl $ - CPU_STACK_ALIGNMENT, esp
call raw_idt_notify
mov ebp, esp
popa
iret
END_CODE
END
