/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * relocate_kernel.S for kexec
 * Created by <nschichan@corp.free.fr> on Thu Oct 12 17:49:57 2006
 */

#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <asm/addrspace.h>

#include <kernel-entry-init.h>

LEAF(relocate_new_kernel)
        PTR_L a0,       arg0
        PTR_L a1,       arg1
        PTR_L a2,       arg2
        PTR_L a3,       arg3

        PTR_L           s0, kexec_indirection_page
        PTR_L           s1, kexec_start_address

process_entry:
        PTR_L           s2, (s0)
        PTR_ADDIU       s0, s0, SZREG

        /*
         * In case of a kdump/crash kernel, the indirection page is not
         * populated as the kernel is directly copied to a reserved location
         */
        beqz            s2, done

        /* destination page */
        and             s3, s2, 0x1
        beq             s3, zero, 1f
        and             s4, s2, ~0x1    /* store destination addr in s4 */
        b               process_entry

1:
        /* indirection page, update s0  */
        and             s3, s2, 0x2
        beq             s3, zero, 1f
        and             s0, s2, ~0x2
        b               process_entry

1:
        /* done page */
        and             s3, s2, 0x4
        beq             s3, zero, 1f
        b               done
1:
        /* source page */
        and             s3, s2, 0x8
        beq             s3, zero, process_entry
        and             s2, s2, ~0x8
        li              s6, (1 << _PAGE_SHIFT) / SZREG

copy_word:
        /* copy page word by word */
        REG_L           s5, (s2)
        REG_S           s5, (s4)
        PTR_ADDIU       s4, s4, SZREG
        PTR_ADDIU       s2, s2, SZREG
        LONG_ADDIU      s6, s6, -1
        beq             s6, zero, process_entry
        b               copy_word

done:
#ifdef CONFIG_SMP
        /* kexec_flag reset is signal to other CPUs what kernel
           was moved to its location. Note - we need relocated address
           of kexec_flag.  */

        bal             1f
 1:     move            t1,ra;
        PTR_LA          t2,1b
        PTR_LA          t0,kexec_flag
        PTR_SUB         t0,t0,t2;
        PTR_ADD         t0,t1,t0;
        LONG_S          zero,(t0)
#endif

#ifdef CONFIG_CPU_CAVIUM_OCTEON
        /* We need to flush I-cache before jumping to new kernel.
         * Unfortunately, this code is cpu-specific.
         */
        .set push
        .set noreorder
        syncw
        syncw
        synci           0($0)
        .set pop
#else
        sync
#endif
        /* jump to kexec_start_address */
        j               s1
        END(relocate_new_kernel)

#ifdef CONFIG_SMP
/*
 * Other CPUs should wait until code is relocated and
 * then start at entry (?) point.
 */
LEAF(kexec_smp_wait)
        PTR_L           a0, s_arg0
        PTR_L           a1, s_arg1
        PTR_L           a2, s_arg2
        PTR_L           a3, s_arg3
        PTR_L           s1, kexec_start_address

        /* Non-relocated address works for args and kexec_start_address ( old
         * kernel is not overwritten). But we need relocated address of
         * kexec_flag.
         */

        bal             1f
1:      move            t1,ra;
        PTR_LA          t2,1b
        PTR_LA          t0,kexec_flag
        PTR_SUB         t0,t0,t2;
        PTR_ADD         t0,t1,t0;

1:      LONG_L          s0, (t0)
        bne             s0, zero,1b

#ifdef USE_KEXEC_SMP_WAIT_FINAL
        kexec_smp_wait_final
#else
        sync
#endif
        j               s1
        END(kexec_smp_wait)
#endif

#ifdef __mips64
       /* all PTR's must be aligned to 8 byte in 64-bit mode */
       .align  3
#endif

/* All parameters to new kernel are passed in registers a0-a3.
 * kexec_args[0..3] are used to prepare register values.
 */

EXPORT(kexec_args)
arg0:   PTR_WD          0x0
arg1:   PTR_WD          0x0
arg2:   PTR_WD          0x0
arg3:   PTR_WD          0x0
        .size   kexec_args,PTRSIZE*4

#ifdef CONFIG_SMP
/*
 * Secondary CPUs may have different kernel parameters in
 * their registers a0-a3. secondary_kexec_args[0..3] are used
 * to prepare register values.
 */
EXPORT(secondary_kexec_args)
s_arg0: PTR_WD          0x0
s_arg1: PTR_WD          0x0
s_arg2: PTR_WD          0x0
s_arg3: PTR_WD          0x0
        .size   secondary_kexec_args,PTRSIZE*4
kexec_flag:
        LONG            0x1

#endif

EXPORT(kexec_start_address)
        PTR_WD          0x0
        .size           kexec_start_address, PTRSIZE

EXPORT(kexec_indirection_page)
        PTR_WD          0
        .size           kexec_indirection_page, PTRSIZE

relocate_new_kernel_end:

EXPORT(relocate_new_kernel_size)
        PTR_WD          relocate_new_kernel_end - relocate_new_kernel
        .size           relocate_new_kernel_size, PTRSIZE