1/* Support for GNU properties in ldconfig. x86 version.
2 Copyright (C) 2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _ELF_READ_PROP_H
20#define _ELF_READ_PROP_H
21
22#include <dl-cache.h>
23
24/* Called for each property in the NT_GNU_PROPERTY_TYPE_0 note of SEGMENT.
25 Return value:
26 false: Continue processing the properties.
27 true : Stop processing the properties.
28 */
29static inline bool __attribute__ ((always_inline))
30read_gnu_property (unsigned int *isal_level, uint32_t type,
31 uint32_t datasz, void *data)
32{
33 /* Property type must be in ascending order. */
34 if (type > GNU_PROPERTY_X86_ISA_1_NEEDED)
35 return true;
36
37 if (type == GNU_PROPERTY_X86_ISA_1_NEEDED)
38 {
39 if (datasz == 4)
40 {
41 /* The size of GNU_PROPERTY_X86_ISA_1_NEEDED must be 4 bytes.
42 There is no point to continue if this type is ill-formed. */
43 unsigned int isa_1_needed = *(unsigned int *) data;
44 _Static_assert (((sizeof (isa_1_needed) * 8)
45 <= (1 << DL_CACHE_HWCAP_ISA_LEVEL_COUNT)),
46 "DL_CACHE_HWCAP_ISA_LEVEL_COUNT is too small");
47 if (isa_1_needed != 0)
48 {
49 unsigned int level;
50 asm ("bsr %1, %0" : "=r" (level) : "g" (isa_1_needed));
51 *isal_level = level;
52 }
53 }
54 return true;
55 }
56
57 return false;
58}
59
60#endif
61