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71c01af52f
* Since __fentry__ is almost the same as _mcount, reuse the code by #including it twice with different #defines around. * Remove LA usages - they are needed in 31-bit mode to clear the top bit, but in 64-bit they appear to do nothing. * Add CFI rule for the nonstandard return register. This rule applies to the current function (binutils generates a new CIE - see gas/dw2gencfi.c:select_cie_for_fde()), so it is not necessary to put __fentry__ into a new file. * Fix CFI offset for %r14. * Add CFI rule for %r0. * Fix unwound value of %r15 being off by 244 bytes. * Unwinding in __fentry__@plt does not work, no plan to fix it - it would require asking linker to generate CFI for return address in %r0. From functional perspective keeping it broken is fine, since the callee did not have a chance to do anything yet. From convenience perspective it would be possible to enhance GDB in the future to treat __fentry__@plt in a special way. * Fix whitespace. * Fix offsets in comments, which were copied from 32-bit code. * 32-bit version will not be implemented, since it's not compatible with the corresponding PLT stubs: they assume %r12 points to GOT, which is not the case for gcc-emitted __fentry__ stub, which runs before the prolog. This patch adds the runtime support in glibc for the -mfentry gcc feature introduced in [1] and [2]. [1] https://gcc.gnu.org/ml/gcc-patches/2018-07/msg00784.html [2] https://gcc.gnu.org/ml/gcc-patches/2018-07/msg00912.html ChangeLog: * sysdeps/s390/s390-64/Versions (__fentry__): Add. * sysdeps/s390/s390-64/s390x-mcount.S: Move the common code to s390x-mcount.h and #include it. * sysdeps/s390/s390-64/s390x-mcount.h: New file. * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (__fentry__): Add.
41 lines
1.5 KiB
ArmAsm
41 lines
1.5 KiB
ArmAsm
/* 64 bit S/390-specific implementation of profiling support.
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Copyright (C) 2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#define MCOUNT_SYMBOL _mcount
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#define MCOUNT_CALLER_OFF 232 /* Pushed by the _mcount stub. */
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#define MCOUNT_CALLEE_REG 14 /* Normal calling convention. */
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#define MCOUNT_RETURN_REG 14
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#include "s390x-mcount.h"
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#undef MCOUNT_SYMBOL
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#undef MCOUNT_CALLER_OFF
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#undef MCOUNT_CALLEE_REG
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#undef MCOUNT_RETURN_REG
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#define MCOUNT_SYMBOL __fentry__
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#define MCOUNT_CALLER_OFF 160 /* Saved %r14. */
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#define MCOUNT_CALLEE_REG 0 /* __fentry__ calling convention. */
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#define MCOUNT_RETURN_REG 1 /* Cannot return via %r0. */
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#include "s390x-mcount.h"
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#undef MCOUNT_SYMBOL
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#undef MCOUNT_CALLER_OFF
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#undef MCOUNT_CALLEE_REG
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#undef MCOUNT_RETURN_REG
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#undef mcount
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weak_alias (_mcount, mcount)
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