binutils-gdb/gdb/common/i386-cpuid.h

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gdb: clean up x86 cpuid implementations We've currently got 3 files doing open coded implementations of cpuid. Each has its own set of workarounds and varying levels of how well they're written and are generally hardcoded to specific cpuid functions. If you try to build the latest gdb as a PIE on an i386 system, the build will fail because one of them lacks PIC workarounds (wrt ebx). Specifically, we have: common/linux-btrace.c: two copies of cpuid asm w/specific args, one has no workarounds while the other implicitly does to avoid memcpy go32-nat.c: two copies of cpuid asm w/specific args, one has workarounds to avoid memcpy gdb/testsuite/gdb.arch/i386-cpuid.h: one general cpuid asm w/many workarounds copied from older gcc Fortunately, that last header there is pretty damn good -- it handles lots of edge cases, the code is nice & tight (uses gcc asm operands rather than manual movs), and is already almost a general library type header. It's also the basis of what is now the public cpuid.h that is shipped with gcc-4.3+. So what I've done is pull that test header out and into gdb/common/ (not sure if there's a better place), synced to the version found in gcc-4.8.0, put a wrapper API around it, and then cut over all the existing call points to this new header. Since the func already has support for "is cpuid supported on this proc", it makes it trivial to push the i386/x86_64 ifdefs down into this wrapper API too. Now it can be safely used for all targets and gcc will elide the unused code for us. I've verified the gdb.arch testsuite still passes, and this code compiles for an armv7a host as well as x86_64. The go32-nat code has been left ifdef-ed out until someone can test & verify the new stuff works (and if it doesn't, figure out how to make the new code work). URL: https://bugs.gentoo.org/467806 Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2013-06-20 00:29:36 +02:00
/* C API for x86 cpuid insn.
Copyright (C) 2007-2014 Free Software Foundation, Inc.
gdb: clean up x86 cpuid implementations We've currently got 3 files doing open coded implementations of cpuid. Each has its own set of workarounds and varying levels of how well they're written and are generally hardcoded to specific cpuid functions. If you try to build the latest gdb as a PIE on an i386 system, the build will fail because one of them lacks PIC workarounds (wrt ebx). Specifically, we have: common/linux-btrace.c: two copies of cpuid asm w/specific args, one has no workarounds while the other implicitly does to avoid memcpy go32-nat.c: two copies of cpuid asm w/specific args, one has workarounds to avoid memcpy gdb/testsuite/gdb.arch/i386-cpuid.h: one general cpuid asm w/many workarounds copied from older gcc Fortunately, that last header there is pretty damn good -- it handles lots of edge cases, the code is nice & tight (uses gcc asm operands rather than manual movs), and is already almost a general library type header. It's also the basis of what is now the public cpuid.h that is shipped with gcc-4.3+. So what I've done is pull that test header out and into gdb/common/ (not sure if there's a better place), synced to the version found in gcc-4.8.0, put a wrapper API around it, and then cut over all the existing call points to this new header. Since the func already has support for "is cpuid supported on this proc", it makes it trivial to push the i386/x86_64 ifdefs down into this wrapper API too. Now it can be safely used for all targets and gcc will elide the unused code for us. I've verified the gdb.arch testsuite still passes, and this code compiles for an armv7a host as well as x86_64. The go32-nat code has been left ifdef-ed out until someone can test & verify the new stuff works (and if it doesn't, figure out how to make the new code work). URL: https://bugs.gentoo.org/467806 Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2013-06-20 00:29:36 +02:00
This file is part of GDB.
This file is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef I386_CPUID_COMMON_H
#define I386_CPUID_COMMON_H
/* Always include the header for the cpu bit defines. */
#include "i386-gcc-cpuid.h"
#if defined(__i386__) || defined(__x86_64__)
/* Return cpuid data for requested cpuid level, as found in returned
eax, ebx, ecx and edx registers. The function checks if cpuid is
supported and returns 1 for valid cpuid information or 0 for
unsupported cpuid level. Pointers may be non-null. */
static __inline int
i386_cpuid (unsigned int __level,
unsigned int *__eax, unsigned int *__ebx,
unsigned int *__ecx, unsigned int *__edx)
{
unsigned int __scratch;
if (!__eax)
__eax = &__scratch;
if (!__ebx)
__ebx = &__scratch;
if (!__ecx)
__ecx = &__scratch;
if (!__edx)
__edx = &__scratch;
return __get_cpuid (__level, __eax, __ebx, __ecx, __edx);
}
#else
static __inline int
i386_cpuid (unsigned int __level,
unsigned int *__eax, unsigned int *__ebx,
unsigned int *__ecx, unsigned int *__edx)
{
return 0;
}
#endif /* i386 && x86_64 */
#endif /* I386_CPUID_COMMON_H */