1 /* powerpc HWCAP/HWCAP2 and AT_PLATFORM data pre-processing.
2 Copyright (C) 2015-2022 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 #include <unistd.h>
20 #include <shlib-compat.h>
21 #include <dl-procinfo.h>
22
23 tcbhead_t __tcb __attribute__ ((visibility ("hidden")));
24
25 /* This function parses the HWCAP/HWCAP2 fields, adding the previous supported
26 ISA bits, as well as converting the AT_PLATFORM string to a number. This
27 data is stored in two global variables that can be used later by the
28 powerpc-specific code to store it into the TCB. */
29 void
__tcb_parse_hwcap_and_convert_at_platform(void)30 __tcb_parse_hwcap_and_convert_at_platform (void)
31 {
32
33 uint64_t h1, h2;
34
35 /* Read AT_PLATFORM string from auxv and convert it to a number. */
36 __tcb.at_platform = _dl_string_platform (GLRO (dl_platform));
37
38 /* Read HWCAP and HWCAP2 from auxv. */
39 h1 = GLRO (dl_hwcap);
40 h2 = GLRO (dl_hwcap2);
41
42 /* hwcap contains only the latest supported ISA, the code checks which is
43 and fills the previous supported ones. */
44
45 if (h2 & PPC_FEATURE2_ARCH_2_07)
46 h1 |= PPC_FEATURE_ARCH_2_06
47 | PPC_FEATURE_ARCH_2_05
48 | PPC_FEATURE_POWER5_PLUS
49 | PPC_FEATURE_POWER5
50 | PPC_FEATURE_POWER4;
51 else if (h1 & PPC_FEATURE_ARCH_2_06)
52 h1 |= PPC_FEATURE_ARCH_2_05
53 | PPC_FEATURE_POWER5_PLUS
54 | PPC_FEATURE_POWER5
55 | PPC_FEATURE_POWER4;
56 else if (h1 & PPC_FEATURE_ARCH_2_05)
57 h1 |= PPC_FEATURE_POWER5_PLUS
58 | PPC_FEATURE_POWER5
59 | PPC_FEATURE_POWER4;
60 else if (h1 & PPC_FEATURE_POWER5_PLUS)
61 h1 |= PPC_FEATURE_POWER5
62 | PPC_FEATURE_POWER4;
63 else if (h1 & PPC_FEATURE_POWER5)
64 h1 |= PPC_FEATURE_POWER4;
65
66 /* Consolidate both HWCAP and HWCAP2 into a single doubleword so that
67 we can read both in a single load later. */
68 __tcb.hwcap = (h1 << 32) | (h2 & 0xffffffff);
69
70 }
71 #if IS_IN (rtld)
72 versioned_symbol (ld, __tcb_parse_hwcap_and_convert_at_platform, \
73 __parse_hwcap_and_convert_at_platform, GLIBC_2_23);
74 #endif
75
76 /* Export __parse_hwcap_and_convert_at_platform in libc.a. This is used by
77 GCC to make sure that the HWCAP/Platform bits are stored in the TCB when
78 using __builtin_cpu_is()/__builtin_cpu_supports() in the static case. */
79 #ifndef SHARED
80 weak_alias (__tcb_parse_hwcap_and_convert_at_platform, \
81 __parse_hwcap_and_convert_at_platform);
82 #endif
83