arch/arm-native/kernel/getcpunumber.c

   1 /*
   2     Copyright © 2015, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <aros/kernel.h>
   7 #include <aros/libcall.h>
   8
   9 #include "kernel_base.h"
  10 #include "kernel_intern.h"
  11
  12 AROS_LH0(cpuid_t, KrnGetCPUNumber,
  13          struct KernelBase *, KernelBase, 41, Kernel)
  14 {
  15     AROS_LIBFUNC_INIT
  16
  17     register unsigned int superSP;
  18     uint32_t tmp;
  19
  20     asm volatile (
  21         "       stmfd   sp!, {lr}               \n"
  22         "       mov     r1, sp                  \n"
  23         "       swi     %[swi_no]               \n"
  24         "       mov     %[superSP], sp          \n"
  25         "       mov     sp, r1                  \n"
  26         "       ldmfd   sp!, {lr}               \n"
  27         : [superSP] "=r" (superSP)
  28         : [swi_no] "I" (6 /*SC_SUPERSTATE*/) : "r1"
  29     );
  30
  31     asm volatile (" mrc p15, 0, %0, c0, c0, 5 " : "=r" (tmp));
  32
  33     if (superSP)
  34     {
  35         asm volatile (
  36             "       stmfd   sp!, {lr}               \n"
  37             "       mov     r1, sp                  \n"
  38             "       mov     sp, %[superSP]          \n"
  39             "       cpsie   i, %[mode_user]         \n"
  40             "       mov     sp, r1                  \n"
  41             "       ldmfd   sp!, {lr}               \n"
  42             : : [superSP] "r" (superSP), [mode_user] "I" (CPUMODE_USER) : "r1" );
  43     }
  44
  45     if (tmp & (2 << 30))
  46     {
  47         return (cpuid_t)(((tmp & 0xF00) >> 4) | (tmp & 0xF));
  48     }
  49
  50     // Uniprocessor System
  51     return (cpuid_t)0;
  52
  53     AROS_LIBFUNC_EXIT
  54 }