/* Software floating-point emulation.
Basic eight-word fraction declaration and manipulation.
Copyright (C) 1997,1998,1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson (rth@cygnus.com),
Jakub Jelinek (jj@ultra.linux.cz) and
Peter Maydell (pmaydell@chiark.greenend.org.uk).
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#ifndef __MATH_EMU_OP_8_H__
#define __MATH_EMU_OP_8_H__
/* We need just a few things from here for op-4, if we ever need some
other macros, they can be added. */
#define _FP_FRAC_DECL_8(X) _FP_W_TYPE X##_f[8]
#define _FP_FRAC_HIGH_8(X) (X##_f[7])
#define _FP_FRAC_LOW_8(X) (X##_f[0])
#define _FP_FRAC_WORD_8(X,w) (X##_f[w])
#define _FP_FRAC_SLL_8(X,N) \
do { \
_FP_I_TYPE _up, _down, _skip, _i; \
_skip = (N) / _FP_W_TYPE_SIZE; \
_up = (N) % _FP_W_TYPE_SIZE; \
_down = _FP_W_TYPE_SIZE - _up; \
if (!_up) \
for (_i = 7; _i >= _skip; --_i) \
X##_f[_i] = X##_f[_i-_skip]; \
else \
{ \
for (_i = 7; _i > _skip; --_i) \
X##_f[_i] = X##_f[_i-_skip] << _up \
| X##_f[_i-_skip-1] >> _down; \
X##_f[_i--] = X##_f[0] << _up; \
} \
for (; _i >= 0; --_i) \
X##_f[_i] = 0; \
} while (0)
#define _FP_FRAC_SRL_8(X,N) \
do { \
_FP_I_TYPE _up, _down, _skip, _i; \
_skip = (N) / _FP_W_TYPE_SIZE; \
_down = (N) % _FP_W_TYPE_SIZE; \
_up = _FP_W_TYPE_SIZE - _down; \
if (!_down) \
for (_i = 0; _i <= 7-_skip; ++_i) \
X##_f[_i] = X##_f[_i+_skip]; \
else \
{ \
for (_i = 0; _i < 7-_skip; ++_i) \
X##_f[_i] = X##_f[_i+_skip] >> _down \
| X##_f[_i+_skip+1] << _up; \
X##_f[_i++] = X##_f[7] >> _down; \
} \
for (; _i < 8; ++_i) \
X##_f[_i] = 0; \
} while (0)
/* Right shift with sticky-lsb.
* What this actually means is that we do a standard right-shift,
* but that if any of the bits that fall off the right hand side
* were one then we always set the LSbit.
*/
#define _FP_FRAC_SRS_8(X,N,size) \
do { \
_FP_I_TYPE _up, _down, _skip, _i; \
_FP_W_TYPE _s; \
_skip = (N) / _FP_W_TYPE_SIZE; \
_down = (N) % _FP_W_TYPE_SIZE; \
_up = _FP_W_TYPE_SIZE - _down; \
for (_s = _i = 0; _i < _skip; ++_i) \
_s |= X##_f[_i]; \
_s |= X##_f[_i] << _up; \
/* s is now != 0 if we want to set the LSbit */ \
if (!_down) \
for (_i = 0; _i <= 7-_skip; ++_i) \
X##_f[_i] = X##_f[_i+_skip]; \
else \
{ \
for (_i = 0; _i < 7-_skip; ++_i) \
X##_f[_i] = X##_f[_i+_skip] >> _down \
| X##_f[_i+_skip+1] << _up; \
X##_f[_i++] = X##_f[7] >> _down; \
} \
for (; _i < 8; ++_i) \
X##_f[_i] = 0; \
/* don't fix the LSB until the very end when we're sure f[0] is stable */ \
X##_f[0] |= (_s != 0); \
} while (0)
#endif
his.form.submit();'>
The hwlat tracer creates a kernel thread at start of the tracer. It is
pinned to a single CPU and will move to the next CPU after each period of
running. If the user modifies the migration thread's affinity, it will not
change after that happens.
The original code created the thread at the first instance it was called,
but later was changed to destroy the thread after the tracer was finished,
and would not be created until the next instance of the tracer was
established. The code that initialized the affinity was only called on the
initial instantiation of the tracer. After that, it was not initialized, and
the previous affinity did not match the current newly created one, making
it appear that the user modified the thread's affinity when it did not, and
the thread failed to migrate again.
Cc: stable@vger.kernel.org
Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>