/* SPDX-License-Identifier: GPL-2.0 */
/*
 * arch/alpha/kernel/head.S
 *
 * initial boot stuff.. At this point, the bootloader has already
 * switched into OSF/1 PAL-code, and loaded us at the correct address
 * (START_ADDR).  So there isn't much left for us to do: just set up
 * the kernel global pointer and jump to the kernel entry-point.
 */

#include <linux/init.h>
#include <asm/asm-offsets.h>
#include <asm/pal.h>
#include <asm/setup.h>

__HEAD
.globl _stext
        .set noreorder
        .globl  __start
        .ent    __start
_stext:
__start:
        .prologue 0
        br      $27,1f
1:      ldgp    $29,0($27)
        /* We need to get current_task_info loaded up...  */
        lda     $8,init_thread_union
        /* ... and find our stack ... */
        lda     $30,0x4000 - SIZEOF_PT_REGS($8)
        /* ... and then we can start the kernel.  */
        jsr     $26,start_kernel
        call_pal PAL_halt
        .end __start

#ifdef CONFIG_SMP
        .align 3
        .globl  __smp_callin
        .ent    __smp_callin
        /* On entry here from SRM console, the HWPCB of the per-cpu
           slot for this processor has been loaded.  We've arranged
           for the UNIQUE value for this process to contain the PCBB
           of the target idle task.  */
__smp_callin:
        .prologue 1
        ldgp    $29,0($27)      # First order of business, load the GP.

        call_pal PAL_rduniq     # Grab the target PCBB.
        mov     $0,$16          # Install it.
        call_pal PAL_swpctx

        lda     $8,0x3fff       # Find "current".
        bic     $30,$8,$8
        
        jsr     $26,smp_callin
        call_pal PAL_halt
        .end __smp_callin
#endif /* CONFIG_SMP */

        #
        # The following two functions are needed for supporting SRM PALcode
        # on the PC164 (at least), since that PALcode manages the interrupt
        # masking, and we cannot duplicate the effort without causing problems
        #

        .align 3
        .globl  cserve_ena
        .ent    cserve_ena
cserve_ena:
        .prologue 0
        bis     $16,$16,$17
        lda     $16,52($31)
        call_pal PAL_cserve
        ret     ($26)
        .end    cserve_ena

        .align 3
        .globl  cserve_dis
        .ent    cserve_dis
cserve_dis:
        .prologue 0
        bis     $16,$16,$17
        lda     $16,53($31)
        call_pal PAL_cserve
        ret     ($26)
        .end    cserve_dis

        #
        # It is handy, on occasion, to make halt actually just loop. 
        # Putting it here means we dont have to recompile the whole
        # kernel.
        #

        .align 3
        .globl  halt
        .ent    halt
halt:
        .prologue 0
        call_pal PAL_halt
        .end    halt