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We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
99 lines
3.4 KiB
C
99 lines
3.4 KiB
C
/* 64 bit S/390-specific implementation of profiling support.
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Copyright (C) 2001-2021 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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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* How profiling works on 64 bit S/390:
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On the start of each function _mcount is called with the address of a
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data word in %r1 (initialized to 0, used for counting). The compiler
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with the option -p generates code of the form:
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STM 6,15,24(15)
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BRAS 13,.LTN0_0
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.LT0_0:
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.LC13: .long .LP0
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.data
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.align 4
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.LP0: .long 0
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.text
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# function profiler
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stg 14,8(15)
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lg 1,.LC13-.LT0_0(13)
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brasl 14,_mcount
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lg 14,8(15)
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The _mcount implementation now has to call __mcount_internal with the
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address of .LP0 as first parameter and the return address as second
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parameter. &.LP0 was loaded to %r1 and the return address is in %r14.
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_mcount may not modify any register.
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Alternatively, at the start of each function __fentry__ is called using a
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single
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# function profiler
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brasl 0,__fentry__
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instruction. In this case %r0 points to the callee, and %r14 points to the
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caller. These values need to be passed to __mcount_internal using the same
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sequence as for _mcount, so the code below is shared between both functions.
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The only major difference is that __fentry__ cannot return through %r0, in
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which the return address is located, because br instruction is a no-op with
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this register. Therefore %r1, which is clobbered by the PLT anyway, is
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used. */
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#define xglue(x, y) x ## y
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#define glue(x, y) xglue(x, y)
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.globl C_SYMBOL_NAME(MCOUNT_SYMBOL)
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.type C_SYMBOL_NAME(MCOUNT_SYMBOL), @function
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cfi_startproc
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.align ALIGNARG(4)
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C_LABEL(MCOUNT_SYMBOL)
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cfi_return_column (glue(r, MCOUNT_CALLEE_REG))
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/* Save the caller-clobbered registers. */
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aghi %r15,-224
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cfi_adjust_cfa_offset (224)
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/* binutils 2.28+: .cfi_val_offset r15, -160 */
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.cfi_escape \
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/* DW_CFA_val_offset */ 0x14, \
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/* r15 */ 0x0f, \
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/* scaled offset */ 0x14
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stmg %r14,%r5,160(%r15)
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cfi_offset (r14, -224)
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cfi_offset (r0, -224+16)
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lg %r2,MCOUNT_CALLER_OFF(%r15) # callers address = 1st param
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lgr %r3,glue(%r, MCOUNT_CALLEE_REG) # callees address = 2nd param
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#ifdef PIC
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brasl %r14,__mcount_internal@PLT
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#else
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brasl %r14,__mcount_internal
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#endif
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/* Pop the saved registers. Please note that `mcount' has no
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return value. */
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lmg %r14,%r5,160(%r15)
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aghi %r15,224
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cfi_adjust_cfa_offset (-224)
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#if MCOUNT_RETURN_REG != MCOUNT_CALLEE_REG
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lgr glue(%r, MCOUNT_RETURN_REG),glue(%r, MCOUNT_CALLEE_REG)
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#endif
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br glue(%r, MCOUNT_RETURN_REG)
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cfi_endproc
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ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(MCOUNT_SYMBOL))
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