/* S/390-specific implementation of profiling support.

   Copyright (C) 2000-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com)

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>

/*

 * How profiling works on S/390:

 * On the start of each function _mcount is called with the address of a

 * data word in %r1 (initialized to 0, used for counting). The compiler

 * with the option -p generates code of the form:

 *

 *         STM    6,15,24(15)

 *         BRAS   13,.LTN0_0

 * .LT0_0:

 * .LC12:  .long  _mcount

 * .LC13:  .long  .LP0

 *         .data

 *         .align 4

 * .LP0:   .long  0

 *         .text

 * # function profiler

 *         st     14,4(15)

 *         l      14,.LC12-.LT0_0(13)

 *         l      1,.LC13-.LT0_0(13)

 *         basr   14,14

 *         l      14,4(15)

 *

 * The _mcount implementation now has to call __mcount_internal with the

 * address of .LP0 as first parameter and the return address as second

 * parameter. &.LP0 was loaded to %r1 and the return address is in %r14.

 * _mcount may not modify any register.

 */

	.globl C_SYMBOL_NAME(_mcount)

	.type C_SYMBOL_NAME(_mcount), @function

	cfi_startproc

	.align ALIGNARG(4)

C_LABEL(_mcount)

	/* Save the caller-clobbered registers.  */

	ahi   %r15,-128

	cfi_adjust_cfa_offset (128)

	stm   %r14,%r5,96(%r15)

	cfi_offset (r14, 0)

	cfi_offset (r15, 4)

	l     %r2,132(%r15)       # callers address  = first parameter

	la    %r2,0(%r2)          # clear bit 0

	la    %r3,0(%r14)         # callees address  = second parameter

#ifdef PIC

	bras  %r14,0f

	.long _GLOBAL_OFFSET_TABLE_-.

0:	al    %r14,0(%r14)

	l     %r14,__mcount_internal@GOT(%r14)

#else

	bras  %r14,0f

	.long __mcount_internal

0:      l     %r14,0(%r14)

#endif

	basr  %r14,%r14

	/*

	 * Pop the saved registers.  Please note that `mcount' has no

	 * return value.

	 */

	lm    %r14,%r5,96(%r15)

	ahi   %r15,128

	cfi_adjust_cfa_offset (-128)

	br    %r14

	cfi_endproc

	ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount))

#undef mcount

weak_alias (_mcount, mcount)