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aarch64: inline __libc_mtag_new_tag

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This is a common operation when heap tagging is enabled, so inline the
instructions instead of using an extern call.
This commit is contained in:
Szabolcs Nagy 2021-02-04 17:05:28 +00:00
parent 40dc773f92
commit 383bc24028
3 changed files with 11 additions and 41 deletions
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1
sysdeps/aarch64/Makefile
View File

@ -41,7 +41,6 @@ endif
ifeq ($(subdir),misc)
sysdep_headers += sys/ifunc.h
sysdep_routines += __mtag_tag_zero_region \
__mtag_new_tag \
__mtag_tag_region
endif

37
sysdeps/aarch64/__mtag_new_tag.S
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@ -1,37 +0,0 @@
/* Copyright (C) 2020-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#ifdef USE_MTAG
.arch armv8.5-a
.arch_extension memtag
/* NB, only supported on variants with 64-bit pointers. */
#define ptr x0
#define xset x1
ENTRY(__libc_mtag_new_tag)
// Guarantee that the new tag is not the same as now.
gmi xset, ptr, xzr
irg ptr, ptr, xset
ret
END (__libc_mtag_new_tag)
#endif /* USE_MTAG */

14
sysdeps/aarch64/libc-mtag.h
View File

@ -52,9 +52,17 @@ __libc_mtag_address_get_tag (void *p)
}
/* Assign a new (random) tag to a pointer P (does not adjust the tag on
the memory addressed).
void *__libc_mtag_new_tag (void*) */
void *__libc_mtag_new_tag (void *);
the memory addressed). */
static __always_inline void *
__libc_mtag_new_tag (void *p)
{
register void *x0 asm ("x0") = p;
register unsigned long x1 asm ("x1");
/* Guarantee that the new tag is not the same as now. */
asm (".inst 0x9adf1401 /* gmi x1, x0, xzr */\n"
".inst 0x9ac11000 /* irg x0, x0, x1 */" : "+r" (x0), "=r" (x1));
return x0;
}
#endif /* USE_MTAG */