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4352e2cc93
When libgcc is built with pac-ret, it requires to autenticate the
unwinding frame based on CFI information. The _dl_tlsdesc_dynamic
uses a custom calling convention, where it is responsible to save
and restore all registers it might use (even volatile).
The pac-ret support added by 1be3d6eb82
was added only on the slow-path, but the fast path also adds DWARF
Register Rule Instruction (cfi_adjust_cfa_offset) since it requires
to save/restore some auxiliary register. It seems that this is not
fully supported neither by libgcc nor AArch64 ABI [1].
Instead, move paciasp/autiasp to function prologue/epilogue to be
used on both fast and slow paths.
I also corrected the _dl_tlsdesc_dynamic comment description, it was
copied from i386 implementation without any adjustment.
Checked on aarch64-linux-gnu with a toolchain built with
--enable-standard-branch-protection on a system with pac-ret
support.
[1] https://github.com/ARM-software/abi-aa/blob/main/aadwarf64/aadwarf64.rst#id1
Reviewed-by: Yury Khrustalev <yury.khrustalev@arm.com>
49 lines
1.4 KiB
C
49 lines
1.4 KiB
C
/* AArch64 tests for unwinding TLSDESC (BZ 32612)
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Copyright (C) 2025 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 <stdlib.h>
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#include <unwind.h>
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#include <support/xdlfcn.h>
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static _Unwind_Reason_Code
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unwind_callback (struct _Unwind_Context* context, void* closure)
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{
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return _URC_NO_REASON;
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}
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/* Assume that TLS variable from tst-tlsdesc-pac-mod.so will trigger
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the slow-path that allocates the required memory with malloc. */
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void *
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malloc (size_t s)
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{
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_Unwind_Backtrace (unwind_callback, NULL);
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return calloc (1, s);
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}
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static int
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do_test (void)
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{
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void *h = xdlopen ("tst-tlsdesc-pac-mod.so", RTLD_LAZY);
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void (*func)(void) = xdlsym (h, "bar");
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func ();
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return 0;
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}
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#include <support/test-driver.c>
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