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[dragonfly.git] / sys / platform / pc32 / isa / ipl.s

/*-
 * Copyright (c) 1989, 1990 William F. Jolitz.
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)ipl.s
 *
 * $FreeBSD: src/sys/i386/isa/ipl.s,v 1.32.2.3 2002/05/16 16:03:56 bde Exp $
 * $DragonFly: src/sys/platform/pc32/isa/ipl.s,v 1.28 2007/01/22 19:37:04 corecode Exp $
 */

#include "use_npx.h"

#include <machine/asmacros.h>
#include <machine/segments.h>
#include <machine/ipl.h>
#include <machine/lock.h>
#include <machine/psl.h>
#include <machine/trap.h>
 
#include "assym.s"

/*
 * AT/386
 * Vector interrupt control section
 *
 *  fpending    - Pending interrupts (set when a masked interrupt occurs)
 *  spending    - Pending software interrupts
 */
        .data
        ALIGN_DATA

        .globl          fastunpend_count
fastunpend_count:       .long   0

        .text
        SUPERALIGN_TEXT

        /*
         * GENERAL NOTES
         *
         *      - fast interrupts are always called with a critical section
         *        held
         *
         *      - we release our critical section when scheduling interrupt
         *        or softinterrupt threads in order so they can preempt
         *        (unless we are called manually from a critical section, in
         *        which case there will still be a critical section and
         *        they won't preempt anyway).
         *
         *      - TD_NEST_COUNT prevents splz from nesting too deeply within
         *        itself.  It is *not* actually an interrupt nesting count.
         *        PCPU(intr_nesting_level) is an interrupt nesting count.
         *
         *      - We have to be careful in regards to local interrupts
         *        occuring simultaniously with our doreti and splz 
         *        processing.
         */

        /*
         * DORETI
         *
         * Handle return from interrupts, traps and syscalls.  This function
         * checks the cpl for unmasked pending interrupts (fast, normal, or
         * soft) and schedules them if appropriate, then irets.
         *
         * If we are in a critical section we cannot run any pending ints
         * nor can be play with mp_lock.
         *
         * NOTE: Since SPLs no longer exist, all callers of this function
         * push $0 for the CPL.  HOWEVER, we *STILL* use the cpl mask within
         * this function to mark fast interrupts which could not be dispatched
         * do to the unavailability of the BGL.
         */
        SUPERALIGN_TEXT
        .globl  doreti
        .type   doreti,@function
doreti:
        FAKE_MCOUNT(bintr)              /* init "from" bintr -> doreti */
        popl    %eax                    /* cpl to restore XXX */
        movl    $0,%eax                 /* irq mask unavailable due to BGL */
        movl    PCPU(curthread),%ebx
        cli                             /* interlock with TDPRI_CRIT */
        cmpl    $0,PCPU(reqflags)       /* short cut if nothing to do */
        je      5f
        cmpl    $TDPRI_CRIT,TD_PRI(%ebx) /* can't unpend if in critical sec */
        jge     5f
        addl    $TDPRI_CRIT,TD_PRI(%ebx) /* force all ints to pending */
doreti_next:
        sti                             /* allow new interrupts */
        movl    %eax,%ecx               /* irq mask unavailable due to BGL */
        notl    %ecx
        cli                             /* disallow YYY remove */
#ifdef SMP
        testl   $RQF_IPIQ,PCPU(reqflags)
        jnz     doreti_ipiq
        testl   $RQF_TIMER,PCPU(reqflags)
        jnz     doreti_timer
#endif
        testl   PCPU(fpending),%ecx     /* check for an unmasked fast int */
        jnz     doreti_fast

        movl    PCPU(spending),%ecx     /* check for a pending software int */
        cmpl    $0,%ecx
        jnz     doreti_soft

        testl   $RQF_AST_MASK,PCPU(reqflags) /* any pending ASTs? */
        jz      2f
        testl   $PSL_VM,TF_EFLAGS(%esp)
        jz      1f
        cmpl    $1,in_vm86call          /* YYY make per 'cpu'? */
        jnz     doreti_ast
1:
        /* ASTs are only applicable when returning to userland */
        testb   $SEL_RPL_MASK,TF_CS(%esp)
        jnz     doreti_ast
2:
        /*
         * Nothing left to do, finish up.  Interrupts are still disabled.
         * %eax contains the mask of IRQ's that are not available due to
         * BGL requirements.  We can only clear RQF_INTPEND if *ALL* pending
         * interrupts have been processed.
         */
        subl    $TDPRI_CRIT,TD_PRI(%ebx)        /* interlocked with cli */
        testl   %eax,%eax
        jnz     5f
        andl    $~RQF_INTPEND,PCPU(reqflags)
5:
        MEXITCOUNT

        /*
         * Restore the segment registers.  Since segment register values
         * can be set from user mode, this can result in a kernel mode
         * exception.  The trap code will revector to the *_fault code
         * which then sets up a T_PROTFLT signal.  If the signal is
         * sent to userland, sendsig() will automatically clean up all
         * the segment registers to avoid a loop.
         */
        .globl  doreti_popl_gs
        .globl  doreti_popl_fs
        .globl  doreti_popl_es
        .globl  doreti_popl_ds
        .globl  doreti_iret
        .globl  doreti_syscall_ret
doreti_syscall_ret:
doreti_popl_gs:
        popl    %gs
doreti_popl_fs:
        popl    %fs
doreti_popl_es:
        popl    %es
doreti_popl_ds:
        popl    %ds
        popal
        addl    $3*4,%esp       /* xflags, trap, err */
doreti_iret:
        iret

        ALIGN_TEXT
        .globl  doreti_iret_fault
doreti_iret_fault:
        subl    $3*4,%esp       /* xflags, trap, err */
        pushal
        pushl   %ds
        .globl  doreti_popl_ds_fault
doreti_popl_ds_fault:
        pushl   %es
        .globl  doreti_popl_es_fault
doreti_popl_es_fault:
        pushl   %fs
        .globl  doreti_popl_fs_fault
doreti_popl_fs_fault:
        pushl   %gs
        .globl  doreti_popl_gs_fault
doreti_popl_gs_fault:
        movl    $0,TF_ERR(%esp) /* XXX should be the error code */
        movl    $T_PROTFLT,TF_TRAPNO(%esp)
        jmp     alltraps_with_regs_pushed

        /*
         * FAST interrupt pending.  NOTE: stack context holds frame structure
         * for fast interrupt procedure, do not do random pushes or pops!
         */
        ALIGN_TEXT
doreti_fast:
        andl    PCPU(fpending),%ecx     /* only check fast ints */
        bsfl    %ecx, %ecx              /* locate the next dispatchable int */
        btrl    %ecx, PCPU(fpending)    /* is it really still pending? */
        jnc     doreti_next
        pushl   %eax                    /* save IRQ mask unavailable for BGL */
                                        /* NOTE: is also CPL in frame */
        call    dofastunpend            /* unpend fast intr %ecx */
        popl    %eax
        jmp     doreti_next

        /*
         *  SOFT interrupt pending
         *
         *  Temporarily back-out our critical section to allow an interrupt
         *  preempt us when we schedule it.  Bump intr_nesting_level to
         *  prevent the switch code from recursing via splz too deeply.
         */
        ALIGN_TEXT
doreti_soft:
        bsfl    %ecx,%ecx               /* locate the next pending softint */
        btrl    %ecx,PCPU(spending)     /* make sure its still pending */
        jnc     doreti_next
        addl    $FIRST_SOFTINT,%ecx     /* actual intr number */
        pushl   %eax
        pushl   %ecx
        incl    TD_NEST_COUNT(%ebx)     /* prevent doreti/splz nesting */
        subl    $TDPRI_CRIT,TD_PRI(%ebx) /* so we can preempt */
        call    sched_ithd              /* YYY must pull in imasks */
        addl    $TDPRI_CRIT,TD_PRI(%ebx)
        decl    TD_NEST_COUNT(%ebx)
        addl    $4,%esp
        popl    %eax
        jmp     doreti_next

        /*
         * AST pending.  We clear RQF_AST_SIGNAL automatically, the others
         * are cleared by the trap as they are processed.
         *
         * Temporarily back-out our critical section because trap() can be
         * a long-winded call, and we want to be more syscall-like.  
         *
         * YYY theoretically we can call lwkt_switch directly if all we need
         * to do is a reschedule.
         */
doreti_ast:
        andl    $~(RQF_AST_SIGNAL|RQF_AST_UPCALL),PCPU(reqflags)
        sti
        movl    %eax,%esi               /* save cpl (can't use stack) */
        movl    $T_ASTFLT,TF_TRAPNO(%esp)
        pushl   %esp                    /* pass frame by reference */
        subl    $TDPRI_CRIT,TD_PRI(%ebx)
        call    trap
        addl    $TDPRI_CRIT,TD_PRI(%ebx)
        addl    $4,%esp
        movl    %esi,%eax               /* restore cpl for loop */
        jmp     doreti_next

#ifdef SMP
        /*
         * IPIQ message pending.  We clear RQF_IPIQ automatically.
         */
doreti_ipiq:
        movl    %eax,%esi               /* save cpl (can't use stack) */
        incl    PCPU(intr_nesting_level)
        andl    $~RQF_IPIQ,PCPU(reqflags)
        subl    $8,%esp                 /* add dummy vec and ppl */
        pushl   %esp                    /* pass frame by reference */
        call    lwkt_process_ipiq_frame
        addl    $12,%esp
        decl    PCPU(intr_nesting_level)
        movl    %esi,%eax               /* restore cpl for loop */
        jmp     doreti_next

doreti_timer:
        movl    %eax,%esi               /* save cpl (can't use stack) */
        incl    PCPU(intr_nesting_level)
        andl    $~RQF_TIMER,PCPU(reqflags)
        subl    $8,%esp                 /* add dummy vec and ppl */
        pushl   %esp                    /* pass frame by reference */
        call    lapic_timer_process_frame
        addl    $12,%esp
        decl    PCPU(intr_nesting_level)
        movl    %esi,%eax               /* restore cpl for loop */
        jmp     doreti_next

#endif

        /*
         * SPLZ() a C callable procedure to dispatch any unmasked pending
         *        interrupts regardless of critical section nesting.  ASTs
         *        are not dispatched.
         *
         *        Use %eax to track those IRQs that could not be processed
         *        due to BGL requirements.
         */
        SUPERALIGN_TEXT

ENTRY(splz)
        pushfl
        pushl   %ebx
        movl    PCPU(curthread),%ebx
        addl    $TDPRI_CRIT,TD_PRI(%ebx)
        movl    $0,%eax

splz_next:
        cli
        movl    %eax,%ecx               /* ecx = ~CPL */
        notl    %ecx
#ifdef SMP
        testl   $RQF_IPIQ,PCPU(reqflags)
        jnz     splz_ipiq
        testl   $RQF_TIMER,PCPU(reqflags)
        jnz     splz_timer
#endif
        testl   PCPU(fpending),%ecx     /* check for an unmasked fast int */
        jnz     splz_fast

        movl    PCPU(spending),%ecx
        cmpl    $0,%ecx
        jnz     splz_soft

        subl    $TDPRI_CRIT,TD_PRI(%ebx)

        /*
         * Nothing left to do, finish up.  Interrupts are still disabled.
         * If our mask of IRQs we couldn't process due to BGL requirements
         * is 0 then there are no pending interrupt sources left and we
         * can clear RQF_INTPEND.
         */
        testl   %eax,%eax
        jnz     5f
        andl    $~RQF_INTPEND,PCPU(reqflags)
5:
        popl    %ebx
        popfl
        ret

        /*
         * FAST interrupt pending
         */
        ALIGN_TEXT
splz_fast:
        andl    PCPU(fpending),%ecx     /* only check fast ints */
        bsfl    %ecx, %ecx              /* locate the next dispatchable int */
        btrl    %ecx, PCPU(fpending)    /* is it really still pending? */
        jnc     splz_next
        pushl   %eax
        call    dofastunpend            /* unpend fast intr %ecx */
        popl    %eax
        jmp     splz_next

        /*
         *  SOFT interrupt pending
         *
         *  Temporarily back-out our critical section to allow the interrupt
         *  preempt us.
         */
        ALIGN_TEXT
splz_soft:
        bsfl    %ecx,%ecx               /* locate the next pending softint */
        btrl    %ecx,PCPU(spending)     /* make sure its still pending */
        jnc     splz_next
        addl    $FIRST_SOFTINT,%ecx     /* actual intr number */
        sti
        pushl   %eax
        pushl   %ecx
        subl    $TDPRI_CRIT,TD_PRI(%ebx)
        incl    TD_NEST_COUNT(%ebx)     /* prevent doreti/splz nesting */
        call    sched_ithd              /* YYY must pull in imasks */
        addl    $TDPRI_CRIT,TD_PRI(%ebx)
        decl    TD_NEST_COUNT(%ebx)     /* prevent doreti/splz nesting */
        addl    $4,%esp
        popl    %eax
        jmp     splz_next

#ifdef SMP
splz_ipiq:
        andl    $~RQF_IPIQ,PCPU(reqflags)
        pushl   %eax
        call    lwkt_process_ipiq
        popl    %eax
        jmp     splz_next

splz_timer:
        andl    $~RQF_TIMER,PCPU(reqflags)
        pushl   %eax
        call    lapic_timer_process
        popl    %eax
        jmp     splz_next
#endif

        /*
         * dofastunpend(%ecx:intr)
         *
         * A FAST interrupt previously made pending can now be run,
         * execute it by pushing a dummy interrupt frame and 
         * calling ithread_fast_handler to execute or schedule it.
         * 
         * ithread_fast_handler() returns 0 if it wants us to unmask
         * further interrupts.
         */
#define PUSH_DUMMY                                                      \
        pushfl ;                /* phys int frame / flags */            \
        pushl   %cs ;           /* phys int frame / cs */               \
        pushl   12(%esp) ;      /* original caller eip */               \
        pushl   $0 ;            /* dummy error code */                  \
        pushl   $0 ;            /* dummy trap type */                   \
        pushl   $0 ;            /* dummy xflags */                      \
        subl    $13*4,%esp ;    /* pushal + 4 seg regs (dummy) + CPL */ \

#define POP_DUMMY                                                       \
        addl    $19*4,%esp ;                                            \

dofastunpend:
        pushl   %ebp                    /* frame for backtrace */
        movl    %esp,%ebp
        PUSH_DUMMY
        pushl   %ecx                    /* last part of intrframe = intr */
        incl    fastunpend_count
        pushl   %esp                    /* pass frame by reference */
        call    ithread_fast_handler    /* returns 0 to unmask */
        addl    $4,%esp                 /* remove pointer, now intr on top */
        cmpl    $0,%eax
        jnz     1f
        movl    MachIntrABI + MACHINTR_INTREN, %eax
        call    *%eax                   /* MachIntrABI.intren(intr) */
1:
        addl    $4,%esp
        POP_DUMMY
        popl    %ebp
        ret