FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/fiq.c

     /*      $NetBSD: fiq.c,v 1.5 2002/04/03 23:33:27 thorpej Exp $  */
     
     /*-
      * SPDX-License-Identifier: BSD-4-Clause
      *
      * Copyright (c) 2001, 2002 Wasabi Systems, Inc.
      * All rights reserved.
      *
      * Written by Jason R. Thorpe for Wasabi Systems, Inc.
     *
     * 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 for the NetBSD Project by
     *      Wasabi Systems, Inc.
     * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     *    or promote products derived from this software without specific prior
     *    written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
     * 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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    
    #include <machine/armreg.h>
    #include <machine/cpufunc.h>
    #include <machine/fiq.h>
    #include <vm/vm.h>
    #include <machine/pcb.h>
    #include <vm/pmap.h>
    #include <machine/cpu.h>
    
    TAILQ_HEAD(, fiqhandler) fiqhandler_stack =
        TAILQ_HEAD_INITIALIZER(fiqhandler_stack);
    
    extern char *fiq_nullhandler_code;
    extern uint32_t fiq_nullhandler_size;
    
    /*
     * fiq_installhandler:
     *
     *      Actually install the FIQ handler down at the FIQ vector.
     *
     *      The FIQ vector is fixed by the hardware definition as the
     *      seventh 32-bit word in the vector page.
     *
     *      Note: If the FIQ is invoked via an extra layer of
     *      indirection, the actual FIQ code store lives in the
     *      data segment, so there is no need to manipulate
     *      the vector page's protection.
     */
    static void
    fiq_installhandler(void *func, size_t size)
    {
            const uint32_t fiqvector = 7 * sizeof(uint32_t);
    
            memcpy((void *)(vector_page + fiqvector), func, size);
            icache_sync((vm_offset_t) fiqvector, size);
    }
    
    /*
     * fiq_claim:
     *
     *      Claim the FIQ vector.
     */
    int
    fiq_claim(struct fiqhandler *fh)
    {
            struct fiqhandler *ofh;
            u_int oldirqstate;
            int error = 0;
    
            if (fh->fh_size > 0x100)
                    return (EFBIG);
    
            oldirqstate = disable_interrupts(PSR_F);
    
            if ((ofh = TAILQ_FIRST(&fiqhandler_stack)) != NULL) {
                   if ((ofh->fh_flags & FH_CANPUSH) == 0) {
                           error = EBUSY;
                           goto out;
                   }
   
                   /* Save the previous FIQ handler's registers. */
                   if (ofh->fh_regs != NULL)
                           fiq_getregs(ofh->fh_regs);
           }
   
           /* Set FIQ mode registers to ours. */
           if (fh->fh_regs != NULL)
                   fiq_setregs(fh->fh_regs);
   
           TAILQ_INSERT_HEAD(&fiqhandler_stack, fh, fh_list);
   
           /* Now copy the actual handler into place. */
           fiq_installhandler(fh->fh_func, fh->fh_size);
   
           /* Make sure FIQs are enabled when we return. */
           oldirqstate &= ~PSR_F;
   
    out:
           restore_interrupts(oldirqstate);
           return (error);
   }
   
   /*
    * fiq_release:
    *
    *      Release the FIQ vector.
    */
   void
   fiq_release(struct fiqhandler *fh)
   {
           u_int oldirqstate;
           struct fiqhandler *ofh;
   
           oldirqstate = disable_interrupts(PSR_F);
   
           /*
            * If we are the currently active FIQ handler, then we
            * need to save our registers and pop the next one back
            * into the vector.
            */
           if (fh == TAILQ_FIRST(&fiqhandler_stack)) {
                   if (fh->fh_regs != NULL)
                           fiq_getregs(fh->fh_regs);
                   TAILQ_REMOVE(&fiqhandler_stack, fh, fh_list);
                   if ((ofh = TAILQ_FIRST(&fiqhandler_stack)) != NULL) {
                           if (ofh->fh_regs != NULL)
                                   fiq_setregs(ofh->fh_regs);
                           fiq_installhandler(ofh->fh_func, ofh->fh_size);
                   }
           } else
                   TAILQ_REMOVE(&fiqhandler_stack, fh, fh_list);
   
           if (TAILQ_FIRST(&fiqhandler_stack) == NULL) {
                   /* Copy the NULL handler back down into the vector. */
                   fiq_installhandler(fiq_nullhandler_code, fiq_nullhandler_size);
   
                   /* Make sure FIQs are disabled when we return. */
                   oldirqstate |= PSR_F;
           }
   
           restore_interrupts(oldirqstate);
   }

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