/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Code that needs to run below 2 GB.
 *
 * Copyright IBM Corp. 2019
 */

#include <linux/linkage.h>
#include <asm/asm-extable.h>
#include <asm/errno.h>
#include <asm/sigp.h>

        .section .amode31.text,"ax"
/*
 * Simplified version of expoline thunk. The normal thunks can not be used here,
 * because they might be more than 2 GB away, and not reachable by the relative
 * branch. No comdat, exrl, etc. optimizations used here, because it only
 * affects a few functions that are not performance-relevant.
 */
        .macro BR_EX_AMODE31_r14
        exrl    0,0f
        j       .
0:      br      %r14
        .endm

/*
 * int _diag14_amode31(unsigned long rx, unsigned long ry1, unsigned long subcode)
 */
SYM_FUNC_START(_diag14_amode31)
        lgr     %r1,%r2
        lgr     %r2,%r3
        lgr     %r3,%r4
        lhi     %r5,-EIO
        sam31
        diag    %r1,%r2,0x14
.Ldiag14_ex:
        ipm     %r5
        srl     %r5,28
.Ldiag14_fault:
        sam64
        lgfr    %r2,%r5
        BR_EX_AMODE31_r14
        EX_TABLE_AMODE31(.Ldiag14_ex, .Ldiag14_fault)
SYM_FUNC_END(_diag14_amode31)

/*
 * int _diag210_amode31(struct diag210 *addr)
 */
SYM_FUNC_START(_diag210_amode31)
        lgr     %r1,%r2
        lhi     %r2,-1
        sam31
        diag    %r1,%r0,0x210
.Ldiag210_ex:
        ipm     %r2
        srl     %r2,28
.Ldiag210_fault:
        sam64
        lgfr    %r2,%r2
        BR_EX_AMODE31_r14
        EX_TABLE_AMODE31(.Ldiag210_ex, .Ldiag210_fault)
SYM_FUNC_END(_diag210_amode31)

/*
 * int diag8c(struct diag8c *addr, struct ccw_dev_id *devno, size_t len)
*/
SYM_FUNC_START(_diag8c_amode31)
        llgf    %r3,0(%r3)
        sam31
        diag    %r2,%r4,0x8c
.Ldiag8c_ex:
        sam64
        lgfr    %r2,%r3
        BR_EX_AMODE31_r14
        EX_TABLE_AMODE31(.Ldiag8c_ex, .Ldiag8c_ex)
SYM_FUNC_END(_diag8c_amode31)
/*
 * int _diag26c_amode31(void *req, void *resp, enum diag26c_sc subcode)
 */
SYM_FUNC_START(_diag26c_amode31)
        lghi    %r5,-EOPNOTSUPP
        sam31
        diag    %r2,%r4,0x26c
.Ldiag26c_ex:
        sam64
        lgfr    %r2,%r5
        BR_EX_AMODE31_r14
        EX_TABLE_AMODE31(.Ldiag26c_ex, .Ldiag26c_ex)
SYM_FUNC_END(_diag26c_amode31)

/*
 * void _diag0c_amode31(unsigned long rx)
 */
SYM_FUNC_START(_diag0c_amode31)
        sam31
        diag    %r2,%r2,0x0c
        sam64
        BR_EX_AMODE31_r14
SYM_FUNC_END(_diag0c_amode31)

/*
 * void _diag308_reset_amode31(void)
 *
 * Calls diag 308 subcode 1 and continues execution
 */
SYM_FUNC_START(_diag308_reset_amode31)
        larl    %r4,ctlregs             # Save control registers
        stctg   %c0,%c15,0(%r4)
        lg      %r2,0(%r4)              # Disable lowcore protection
        nilh    %r2,0xefff
        larl    %r4,ctlreg0
        stg     %r2,0(%r4)
        lctlg   %c0,%c0,0(%r4)
        larl    %r4,fpctl               # Floating point control register
        stfpc   0(%r4)
        larl    %r4,prefix              # Save prefix register
        stpx    0(%r4)
        larl    %r4,prefix_zero # Set prefix register to 0
        spx     0(%r4)
        larl    %r4,continue_psw        # Save PSW flags
        epsw    %r2,%r3
        stm     %r2,%r3,0(%r4)
        larl    %r4,.Lrestart_part2     # Setup restart PSW at absolute 0
        larl    %r3,restart_diag308_psw
        og      %r4,0(%r3)              # Save PSW
        lghi    %r3,0
        sturg   %r4,%r3                 # Use sturg, because of large pages
        lghi    %r1,1
        lghi    %r0,0
        diag    %r0,%r1,0x308
.Lrestart_part2:
        lhi     %r0,0                   # Load r0 with zero
        lhi     %r1,2                   # Use mode 2 = ESAME (dump)
        sigp    %r1,%r0,SIGP_SET_ARCHITECTURE   # Switch to ESAME mode
        sam64                           # Switch to 64 bit addressing mode
        larl    %r4,ctlregs             # Restore control registers
        lctlg   %c0,%c15,0(%r4)
        larl    %r4,fpctl               # Restore floating point ctl register
        lfpc    0(%r4)
        larl    %r4,prefix              # Restore prefix register
        spx     0(%r4)
        larl    %r4,continue_psw        # Restore PSW flags
        larl    %r2,.Lcontinue
        stg     %r2,8(%r4)
        lpswe   0(%r4)
.Lcontinue:
        BR_EX_AMODE31_r14
SYM_FUNC_END(_diag308_reset_amode31)

        .section .amode31.data,"aw",@progbits
        .balign 8
SYM_DATA_LOCAL(restart_diag308_psw,     .long 0x00080000,0x80000000)
SYM_DATA_LOCAL(continue_psw,            .quad 0,0)
SYM_DATA_LOCAL(ctlreg0,                 .quad 0)
SYM_DATA_LOCAL(ctlregs,                 .fill 16,8,0)
SYM_DATA_LOCAL(fpctl,                   .long 0)
SYM_DATA_LOCAL(prefix,                  .long 0)
SYM_DATA_LOCAL(prefix_zero,             .long 0)