osfmk/ppc/mcount.s

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 #include <ppc/asm.h>
  23 #include <ppc/proc_reg.h>
  24 #include <assym.s>
  25 #include <debug.h>
  26 #include <mach/ppc/vm_param.h>
  27 #include <ppc/exception.h>
  28
  29
  30 /*
  31  * The compiler generates calls to this function and passes address
  32  * of caller of the function [ from which mcount is called ] as the
  33  * first parameter.
  34  * mcount disables interrupts prior to call mcount() and restores
  35  * interrupt upon return.
  36  * To prevent recursive calls to mcount(), a flag, mcountOff, is set
  37  * in cpu_flags per_proc.
  38  */
  39
  40                         .align 4
  41                         .globl mcount
  42 mcount:
  43                 mflr r0                                                                         ; Load lr
  44                 stw r0,8(r1)                                                            ; Save lr on the stack
  45                 stwu r1,-64(r1)                                                         ; Get a stack frame
  46                 mfmsr   r9                                                                      ; Get msr
  47                 rlwinm  r9,r9,0,MSR_FP_BIT+1,MSR_FP_BIT-1       ; Force floating point off
  48                 rlwinm  r9,r9,0,MSR_VEC_BIT+1,MSR_VEC_BIT-1     ; Force vectors off
  49                 rlwinm  r8,r9,0,MSR_EE_BIT+1,MSR_EE_BIT-1       ; Turn off interruptions
  50                 mtmsr   r8                                                                      ; Update msr
  51                 isync
  52                 mfsprg  r7,1                                                            ; Get the current activation
  53                 lwz             r7,ACT_PER_PROC(r7)                                     ; Get the per_proc block
  54                 lhz             r6,PP_CPU_FLAGS(r7)                                     ; Get  cpu flags
  55                 ori             r5,r6,mcountOff                                         ;
  56                 cmplw   r5,r6                                                           ; is mount off
  57                 beq             mcount_ret                                                      ; return if off
  58                 sth             r5,PP_CPU_FLAGS(r7)                                     ; Update cpu_flags
  59                 stw     r9,FM_ARG0(r1)                                                  ; Save MSR
  60                 mr r4, r0
  61                 bl      _mcount                                                                 ; Call the C routine
  62                 lwz     r9,FM_ARG0(r1)
  63                 mfsprg  r7,1                                                            ; Get the current activation
  64                 lwz             r7,ACT_PER_PROC(r7)                                     ; Get the per_proc block
  65                 lhz             r6,PP_CPU_FLAGS(r7)                                     ; Get CPU number
  66                 li              r5,mcountOff                                            ;
  67                 andc            r6,r6,r5                                                ; Clear mcount_off
  68                 sth             r6,PP_CPU_FLAGS(r7)                                     ; Save cpu_flags
  69 mcount_ret:
  70                 addi r1,r1,64
  71                 mtmsr   r9                                                                      ; Restore MSR
  72                 lwz r0,8(r1)
  73                 mtlr r0
  74                 blr
  75