/* SPDX-License-Identifier: GPL-2.0 */
/*
 * S390 kdump lowlevel functions (new kernel)
 *
 * Copyright IBM Corp. 2011
 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
 */

#include <asm/sigp.h>

#define DATAMOVER_ADDR  0x4000
#define COPY_PAGE_ADDR  0x6000

#ifdef CONFIG_CRASH_DUMP

#
# kdump entry (new kernel - not yet relocated)
#
# Note: This code has to be position independent
#

SYM_CODE_START_LOCAL(startup_kdump)
        lhi     %r1,2                           # mode 2 = esame (dump)
        sigp    %r1,%r0,SIGP_SET_ARCHITECTURE   # Switch to esame mode
        sam64                                   # Switch to 64 bit addressing
        basr    %r13,0
.Lbase:
        larl    %r2,.Lbase_addr                 # Check, if we have been
        lg      %r2,0(%r2)                      # already relocated:
        clgr    %r2,%r13                        #
        jne     .Lrelocate                      # No : Start data mover
        lghi    %r2,0                           # Yes: Start kdump kernel
        brasl   %r14,startup_kdump_relocated

.Lrelocate:
        larl    %r4,startup
        lg      %r2,0x418(%r4)                  # Get kdump base
        lg      %r3,0x420(%r4)                  # Get kdump size

        larl    %r10,.Lcopy_start               # Source of data mover
        lghi    %r8,DATAMOVER_ADDR              # Target of data mover
        mvc     0(256,%r8),0(%r10)              # Copy data mover code

        agr     %r8,%r2                         # Copy data mover to
        mvc     0(256,%r8),0(%r10)              # reserved mem

        lghi    %r14,DATAMOVER_ADDR             # Jump to copied data mover
        basr    %r14,%r14
.Lbase_addr:
        .quad   .Lbase

#
# kdump data mover code (runs at address DATAMOVER_ADDR)
#
# r2: kdump base address
# r3: kdump size
#
.Lcopy_start:
        basr    %r13,0                          # Base
0:
        lgr     %r11,%r2                        # Save kdump base address
        lgr     %r12,%r2
        agr     %r12,%r3                        # Compute kdump end address

        lghi    %r5,0
        lghi    %r10,COPY_PAGE_ADDR             # Load copy page address
1:
        mvc     0(256,%r10),0(%r5)              # Copy old kernel to tmp
        mvc     0(256,%r5),0(%r11)              # Copy new kernel to old
        mvc     0(256,%r11),0(%r10)             # Copy tmp to new
        aghi    %r11,256
        aghi    %r5,256
        clgr    %r11,%r12
        jl      1b

        lg      %r14,.Lstartup_kdump-0b(%r13)
        basr    %r14,%r14                       # Start relocated kernel
.Lstartup_kdump:
        .long   0x00000000,0x00000000 + startup_kdump_relocated
.Lcopy_end:

#
# Startup of kdump (relocated new kernel)
#
        .balign 2
startup_kdump_relocated:
        basr    %r13,0
0:      lpswe   .Lrestart_psw-0b(%r13)          # Start new kernel...
SYM_CODE_END(startup_kdump)
        .balign 8
.Lrestart_psw:
        .quad   0x0000000080000000,0x0000000000000000 + startup
#else
SYM_CODE_START_LOCAL(startup_kdump)
        larl    %r13,startup_kdump_crash
        lpswe   0(%r13)
SYM_CODE_END(startup_kdump)
        .balign 8
startup_kdump_crash:
        .quad   0x0002000080000000,0x0000000000000000 + startup_kdump_crash
#endif /* CONFIG_CRASH_DUMP */