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ee7f4c54e1
This patch adds a new feature for powerpc. In order to get faster
access to the HWCAP3/HWCAP4 masks, similar to HWCAP/HWCAP2 (i.e. for
implementing __builtin_cpu_supports() in GCC) without the overhead of
reading them from the auxiliary vector, we now reserve space for them
in the TCB.
Suggested-by: Peter Bergner <bergner@linux.ibm.com>
Reviewed-by: Peter Bergner <bergner@linux.ibm.com>
(cherry picked from commit 3ab9b88e2a)
97 lines
3.5 KiB
C
97 lines
3.5 KiB
C
/* powerpc HWCAP/HWCAP2 and AT_PLATFORM data pre-processing.
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Copyright (C) 2015-2024 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 <unistd.h>
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#include <shlib-compat.h>
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#include <dl-procinfo.h>
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#include <cpu-features.c>
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tcbhead_t __tcb __attribute__ ((visibility ("hidden")));
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/* This function parses the HWCAP/HWCAP2 fields, adding the previous supported
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ISA bits, as well as converting the AT_PLATFORM string to a number. This
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data is stored in two global variables that can be used later by the
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powerpc-specific code to store it into the TCB. */
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void
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__tcb_parse_hwcap_and_convert_at_platform (void)
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{
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uint64_t h1, h2, h3, h4;
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/* Read AT_PLATFORM string from auxv and convert it to a number. */
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__tcb.at_platform = _dl_string_platform (GLRO (dl_platform));
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/* Read HWCAP and HWCAP2 from auxv. */
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h1 = GLRO (dl_hwcap);
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h2 = GLRO (dl_hwcap2);
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h3 = GLRO (dl_hwcap3);
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h4 = GLRO (dl_hwcap4);
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/* hwcap contains only the latest supported ISA, the code checks which is
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and fills the previous supported ones. */
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if (h2 & PPC_FEATURE2_ARCH_2_07)
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h1 |= PPC_FEATURE_ARCH_2_06
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| PPC_FEATURE_ARCH_2_05
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| PPC_FEATURE_POWER5_PLUS
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| PPC_FEATURE_POWER5
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| PPC_FEATURE_POWER4;
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else if (h1 & PPC_FEATURE_ARCH_2_06)
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h1 |= PPC_FEATURE_ARCH_2_05
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| PPC_FEATURE_POWER5_PLUS
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| PPC_FEATURE_POWER5
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| PPC_FEATURE_POWER4;
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else if (h1 & PPC_FEATURE_ARCH_2_05)
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h1 |= PPC_FEATURE_POWER5_PLUS
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| PPC_FEATURE_POWER5
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| PPC_FEATURE_POWER4;
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else if (h1 & PPC_FEATURE_POWER5_PLUS)
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h1 |= PPC_FEATURE_POWER5
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| PPC_FEATURE_POWER4;
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else if (h1 & PPC_FEATURE_POWER5)
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h1 |= PPC_FEATURE_POWER4;
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uint64_t array_hwcaps[] = { h1, h2, h3, h4 };
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init_cpu_features (&GLRO(dl_powerpc_cpu_features), array_hwcaps);
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/* Consolidate both HWCAP and HWCAP2 into a single doubleword so that
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we can read both in a single load later. */
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__tcb.hwcap = (h1 << 32) | (h2 & 0xffffffff);
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/* Consolidate both HWCAP3 and HWCAP4 into a single doubleword so that
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we can read both in a single load later. */
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__tcb.hwcap_extn = (h3 << 32) | (h4 & 0xffffffff);
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}
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#if IS_IN (rtld)
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versioned_symbol (ld, __tcb_parse_hwcap_and_convert_at_platform, \
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__parse_hwcap_and_convert_at_platform, GLIBC_2_23);
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versioned_symbol (ld, __tcb_parse_hwcap_and_convert_at_platform, \
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__parse_hwcap_3_4_and_convert_at_platform, GLIBC_2_39);
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#endif
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/* Export __parse_hwcap_and_convert_at_platform in libc.a. This is used by
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GCC to make sure that the HWCAP/Platform bits are stored in the TCB when
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using __builtin_cpu_is()/__builtin_cpu_supports() in the static case. */
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#ifndef SHARED
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weak_alias (__tcb_parse_hwcap_and_convert_at_platform, \
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__parse_hwcap_and_convert_at_platform);
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weak_alias (__tcb_parse_hwcap_and_convert_at_platform, \
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__parse_hwcap_3_4_and_convert_at_platform);
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#endif
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