1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26 /*
  27  * Copyright 2015, Joyent, Inc.
  28  */
  29 
  30 #include <sys/cpuvar.h>
  31 #include <sys/stack.h>
  32 #include <vm/seg_kp.h>
  33 #include <sys/proc.h>
  34 #include <sys/pset.h>
  35 #include <sys/sysmacros.h>
  36 
  37 /*
  38  * Use a slightly larger thread stack size for interrupt threads rather than the
  39  * default. This is useful for cases where the networking stack may do an rx and
  40  * a tx in the context of a single interrupt and when combined with various
  41  * promisc hooks that need memory, can cause us to get dangerously close to the
  42  * edge of the traditional stack sizes. This is only a few pages more than a
  43  * traditional stack and given that we don't have that many interrupt threads,
  44  * the memory costs end up being more than worthwhile.
  45  */
  46 #define LL_INTR_STKSZ   (32 * 1024)
  47 
  48 /*
  49  * Create and initialize an interrupt thread.
  50  */
  51 static void
  52 thread_create_intr(cpu_t *cp)
  53 {
  54         kthread_t *tp;
  55 
  56         tp = thread_create(NULL, LL_INTR_STKSZ,
  57             (void (*)())thread_create_intr, NULL, 0, &p0, TS_ONPROC, 0);
  58 
  59         /*
  60          * Set the thread in the TS_FREE state.  The state will change
  61          * to TS_ONPROC only while the interrupt is active.  Think of these
  62          * as being on a private free list for the CPU.  Being TS_FREE keeps
  63          * inactive interrupt threads out of debugger thread lists.
  64          *
  65          * We cannot call thread_create with TS_FREE because of the current
  66          * checks there for ONPROC.  Fix this when thread_create takes flags.
  67          */
  68         THREAD_FREEINTR(tp, cp);
  69 
  70         /*
  71          * Nobody should ever reference the credentials of an interrupt
  72          * thread so make it NULL to catch any such references.
  73          */
  74         tp->t_cred = NULL;
  75         tp->t_flag |= T_INTR_THREAD;
  76         tp->t_cpu = cp;
  77         tp->t_bound_cpu = cp;
  78         tp->t_disp_queue = cp->cpu_disp;
  79         tp->t_affinitycnt = 1;
  80         tp->t_preempt = 1;
  81 
  82         /*
  83          * Don't make a user-requested binding on this thread so that
  84          * the processor can be offlined.
  85          */
  86         tp->t_bind_cpu = PBIND_NONE; /* no USER-requested binding */
  87         tp->t_bind_pset = PS_NONE;
  88 
  89 #if defined(__i386) || defined(__amd64)
  90         tp->t_stk -= STACK_ALIGN;
  91         *(tp->t_stk) = 0;            /* terminate intr thread stack */
  92 #endif
  93 
  94         /*
  95          * Link onto CPU's interrupt pool.
  96          */
  97         tp->t_link = cp->cpu_intr_thread;
  98         cp->cpu_intr_thread = tp;
  99 }
 100 
 101 /*
 102  * Allocate a given number of interrupt threads for a given CPU.  These threads
 103  * will get freed by cpu_destroy_bound_threads() when CPU gets unconfigured.
 104  *
 105  * Note, high level interrupts are always serviced using cpu_intr_stack and are
 106  * not allowed to block. Low level interrupts or soft-interrupts use the
 107  * kthread_t's that we create through the calls to thread_create_intr().
 108  */
 109 void
 110 cpu_intr_alloc(cpu_t *cp, int n)
 111 {
 112         int i;
 113 
 114         for (i = 0; i < n; i++)
 115                 thread_create_intr(cp);
 116 
 117         cp->cpu_intr_stack = (caddr_t)segkp_get(segkp, INTR_STACK_SIZE,
 118             KPD_HASREDZONE | KPD_NO_ANON | KPD_LOCKED) +
 119             INTR_STACK_SIZE - SA(MINFRAME);
 120 }