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| 2 | /* contrib/mips-msa/linux.c
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| 3 | *
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| 4 | * Copyright (c) 2020-2023 Cosmin Truta
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| 5 | * Copyright (c) 2016 Glenn Randers-Pehrson
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| 6 | * Written by Mandar Sahastrabuddhe, 2016.
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| 7 | * Updated by Sui Jingfeng, 2021.
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| 8 | *
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| 9 | * This code is released under the libpng license.
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| 10 | * For conditions of distribution and use, see the disclaimer
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| 11 | * and license in png.h
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| 12 | *
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| 13 | * On Linux, png_have_msa is implemented by reading the pseudo-file
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| 14 | * "/proc/self/auxv".
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| 15 | *
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| 16 | * See contrib/mips-msa/README before reporting bugs.
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| 17 | *
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| 18 | * STATUS: SUPPORTED
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| 19 | * BUG REPORTS: [email protected]
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| 20 | */
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| 21 |
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| 22 | #include <elf.h>
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| 23 | #include <fcntl.h>
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| 24 | #include <stdlib.h>
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| 25 | #include <unistd.h>
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| 26 |
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| 27 | static int
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| 28 | png_have_msa(png_structp png_ptr)
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| 29 | {
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| 30 | Elf64_auxv_t aux;
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| 31 | int fd;
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| 32 | int has_msa = 0;
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| 33 |
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| 34 | fd = open("/proc/self/auxv", O_RDONLY);
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| 35 | if (fd >= 0)
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| 36 | {
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| 37 | while (read(fd, &aux, sizeof(Elf64_auxv_t)) == sizeof(Elf64_auxv_t))
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| 38 | {
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| 39 | if (aux.a_type == AT_HWCAP)
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| 40 | {
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| 41 | uint64_t hwcap = aux.a_un.a_val;
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| 42 |
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| 43 | has_msa = (hwcap >> 1) & 1;
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| 44 | break;
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| 45 | }
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| 46 | }
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| 47 | close(fd);
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| 48 | }
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| 49 | #ifdef PNG_WARNINGS_SUPPORTED
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| 50 | else
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| 51 | png_warning(png_ptr, "/proc/self/auxv open failed");
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| 52 | #endif
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| 53 |
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| 54 | return has_msa;
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| 55 | }
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