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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* s390x assembly macros
*
* Copyright (c) 2017 Red Hat Inc
* Copyright (c) 2020, 2021 IBM Corp.
*
* Authors:
* Janosch Frank <frankja@linux.ibm.com>
* Pierre Morel <pmorel@linux.ibm.com>
* David Hildenbrand <david@redhat.com>
*/
#include <asm/asm-offsets.h>
/*
* Exception handler macro that saves registers on the stack,
* allocates stack space and calls the C handler function. Afterwards
* we re-load the registers and load the old PSW.
*/
.macro CALL_INT_HANDLER c_func, old_psw
SAVE_REGS_STACK
/* Save the stack address in GR2 which is the first function argument */
lgr %r2, %r15
/* Allocate stack space for called C function, as specified in s390 ELF ABI */
slgfi %r15, STACK_FRAME_SIZE
/*
* Save the address of the interrupt stack into the back chain
* of the called function.
*/
stg %r2, STACK_FRAME_INT_BACKCHAIN(%r15)
brasl %r14, \c_func
algfi %r15, STACK_FRAME_SIZE
RESTORE_REGS_STACK
lpswe \old_psw
.endm
/* Save registers on the stack (r15), so we can have stacked interrupts. */
.macro SAVE_REGS_STACK
/* Allocate a full stack frame */
slgfi %r15, STACK_FRAME_INT_SIZE
/* Store registers r0 to r14 on the stack */
stmg %r2, %r15, STACK_FRAME_INT_GRS0(%r15)
stg %r0, STACK_FRAME_INT_GRS1(%r15)
stg %r1, STACK_FRAME_INT_GRS1 + 8(%r15)
/* Store the gr15 value before we allocated the new stack */
lgr %r0, %r15
algfi %r0, STACK_FRAME_INT_SIZE
stg %r0, 13 * 8 + STACK_FRAME_INT_GRS0(%r15)
stg %r0, STACK_FRAME_INT_BACKCHAIN(%r15)
/*
* Store CR0 and load initial CR0 so AFP is active and we can
* access all fprs to save them.
*/
stctg %c0,%c15,STACK_FRAME_INT_CRS(%r15)
larl %r1, initial_cr0
lctlg %c0, %c0, 0(%r1)
/* Save fp register on stack: offset to SP is multiple of reg number */
.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
std \i, \i * 8 + STACK_FRAME_INT_FPRS(%r15)
.endr
/* Save fpc */
stfpc STACK_FRAME_INT_FPC(%r15)
.endm
/* Restore the register in reverse order */
.macro RESTORE_REGS_STACK
/* Restore fpc */
lfpc STACK_FRAME_INT_FPC(%r15)
/* Restore fp register from stack: SP still where it was left */
/* and offset to SP is a multiple of reg number */
.irp i, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
ld \i, \i * 8 + STACK_FRAME_INT_FPRS(%r15)
.endr
/* Load CR0 back */
lctlg %c0, %c15, STACK_FRAME_INT_CRS(%r15)
/* Load the registers from stack */
lg %r0, STACK_FRAME_INT_GRS1(%r15)
lg %r1, STACK_FRAME_INT_GRS1 + 8(%r15)
lmg %r2, %r15, STACK_FRAME_INT_GRS0(%r15)
.endm