/* 64 bit S/390-specific implemetation of profiling support. Copyright (C) 2001-2016 Free Software Foundation, Inc. Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com) This file is part of the GNU C Library. 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 64 bit 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: .LC13: .long .LP0 .data .align 4 .LP0: .long 0 .text # function profiler stg 14,4(15) lg 1,.LC13-.LT0_0(13) brasl 14,_mcount lg 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. */ aghi %r15,-224 cfi_adjust_cfa_offset (224) stmg %r14,%r5,160(%r15) cfi_offset (r14, 0) cfi_offset (r15, 8) lg %r2,232(%r15) # callers address = first parameter la %r2,0(%r2) # clear bit 0 la %r3,0(%r14) # callees address = second parameter #ifdef PIC brasl %r14,__mcount_internal@PLT #else brasl %r14,__mcount_internal #endif /* Pop the saved registers. Please note that `mcount' has no return value. */ lmg %r14,%r5,160(%r15) aghi %r15,224 cfi_adjust_cfa_offset (-224) br %r14 cfi_endproc ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount)) #undef mcount weak_alias (_mcount, mcount)