arch/alpha/kernel/head.S

   1 /*
   2  * arch/alpha/kernel/head.S
   3  *
   4  * initial boot stuff.. At this point, the bootloader has already
   5  * switched into OSF/1 PAL-code, and loaded us at the correct address
   6  * (START_ADDR).  So there isn't much left for us to do: just set up
   7  * the kernel global pointer and jump to the kernel entry-point.
   8  */
   9
  10 #include <linux/init.h>
  11 #include <asm/asm-offsets.h>
  12 #include <asm/pal.h>
  13 #include <asm/setup.h>
  14
  15 __HEAD
  16 .globl _stext
  17         .set noreorder
  18         .globl  __start
  19         .ent    __start
  20 _stext:
  21 __start:
  22         .prologue 0
  23         br      $27,1f
  24 1:      ldgp    $29,0($27)
  25         /* We need to get current_task_info loaded up...  */
  26         lda     $8,init_thread_union
  27         /* ... and find our stack ... */
  28         lda     $30,0x4000 - SIZEOF_PT_REGS($8)
  29         /* ... and then we can start the kernel.  */
  30         jsr     $26,start_kernel
  31         call_pal PAL_halt
  32         .end __start
  33
  34 #ifdef CONFIG_SMP
  35         .align 3
  36         .globl  __smp_callin
  37         .ent    __smp_callin
  38         /* On entry here from SRM console, the HWPCB of the per-cpu
  39            slot for this processor has been loaded.  We've arranged
  40            for the UNIQUE value for this process to contain the PCBB
  41            of the target idle task.  */
  42 __smp_callin:
  43         .prologue 1
  44         ldgp    $29,0($27)      # First order of business, load the GP.
  45
  46         call_pal PAL_rduniq     # Grab the target PCBB.
  47         mov     $0,$16          # Install it.
  48         call_pal PAL_swpctx
  49
  50         lda     $8,0x3fff       # Find "current".
  51         bic     $30,$8,$8
  52
  53         jsr     $26,smp_callin
  54         call_pal PAL_halt
  55         .end __smp_callin
  56 #endif /* CONFIG_SMP */
  57
  58         #
  59         # The following two functions are needed for supporting SRM PALcode
  60         # on the PC164 (at least), since that PALcode manages the interrupt
  61         # masking, and we cannot duplicate the effort without causing problems
  62         #
  63
  64         .align 3
  65         .globl  cserve_ena
  66         .ent    cserve_ena
  67 cserve_ena:
  68         .prologue 0
  69         bis     $16,$16,$17
  70         lda     $16,52($31)
  71         call_pal PAL_cserve
  72         ret     ($26)
  73         .end    cserve_ena
  74
  75         .align 3
  76         .globl  cserve_dis
  77         .ent    cserve_dis
  78 cserve_dis:
  79         .prologue 0
  80         bis     $16,$16,$17
  81         lda     $16,53($31)
  82         call_pal PAL_cserve
  83         ret     ($26)
  84         .end    cserve_dis
  85
  86         #
  87         # It is handy, on occasion, to make halt actually just loop.
  88         # Putting it here means we dont have to recompile the whole
  89         # kernel.
  90         #
  91
  92         .align 3
  93         .globl  halt
  94         .ent    halt
  95 halt:
  96         .prologue 0
  97         call_pal PAL_halt
  98         .end    halt