forked from Imagelibrary/binutils-gdb
e1b2624a08
On various GNU Elf architectures, including AArch64, ARM, s390/s390x, ppc32/64, and sparc32/64, the dynamic loader passes HWCAP as a parameter to each ifunc resolver. Currently there is an open glibc Bugzilla that requests this to be generalized to all architectures: https://sourceware.org/bugzilla/show_bug.cgi?id=19766 And various ifunc resolvers already rely on receiving HWCAP. Currently GDB always calls an ifunc resolver without any arguments; thus the resolver may receive garbage, and based on that, the resolver may decide to return a function that is not suited for the given platform. This patch always passes HWCAP to ifunc resolvers, even on systems where the dynamic loader currently behaves otherwise. The rationale is that (1) the dynamic loader may get adjusted on those systems as well in the future; (2) passing an unused argument should not cause a problem with existing resolvers; and (3) the logic is much simpler without such a distinction. gdb/ChangeLog: * elfread.c (auxv.h): New include. (elf_gnu_ifunc_resolve_addr): Pass HWCAP to ifunc resolver. gdb/testsuite/ChangeLog: * gdb.base/gnu-ifunc-lib.c (resolver_hwcap): New external variable declaration. (gnu_ifunc): Add parameter hwcap. Store it in resolver_hwcap. * gdb.base/gnu-ifunc.c (resolver_hwcap): New global variable. * gdb.base/gnu-ifunc.exp: Add test to verify that the resolver received HWCAP as its argument.
66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
/* This testcase is part of GDB, the GNU debugger.
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Copyright 2009-2016 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <assert.h>
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int
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init_stub (int arg)
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{
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return 0;
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}
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int
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final (int arg)
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{
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return arg + 1;
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}
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/* Make differentiation of how the gnu_ifunc call resolves before and after
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calling gnu_ifunc_pre. This ensures the resolved function address is not
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being cached anywhere for the debugging purposes. */
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volatile int gnu_ifunc_initialized;
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/* This stores the argument received by the ifunc resolver. */
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volatile unsigned long resolver_hwcap = -1;
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static void
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gnu_ifunc_pre (void)
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{
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assert (!gnu_ifunc_initialized);
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gnu_ifunc_initialized = 1;
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}
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extern int gnu_ifunc (int arg);
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int
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main (void)
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{
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int i;
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gnu_ifunc_pre ();
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i = gnu_ifunc (1); /* break-at-call */
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assert (i == 2);
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gnu_ifunc (2); /* break-at-nextcall */
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return 0; /* break-at-exit */
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}
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