projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| d4697bc9 | 1 | /* Copyright (C) 2012-2014 Free Software Foundation, Inc. |
| b8d7c096 CM |
2 | This file is part of the GNU C Library. |
| 3 | ||
| 4 | The GNU C Library is free software; you can redistribute it and/or | |
| 5 | modify it under the terms of the GNU Lesser General Public | |
| 6 | License as published by the Free Software Foundation; either | |
| 7 | version 2.1 of the License, or (at your option) any later version. | |
| 8 | ||
| 9 | The GNU C Library is distributed in the hope that it will be useful, | |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 12 | Lesser General Public License for more details. | |
| 13 | ||
| 14 | You should have received a copy of the GNU Lesser General Public | |
| 15 | License along with the GNU C Library. If not, see | |
| 16 | <http://www.gnu.org/licenses/>. */ | |
| 17 | ||
| 18 | #include <errno.h> | |
| 19 | #include <stddef.h> | |
| 20 | #include <fcntl.h> | |
| 21 | #include <unistd.h> | |
| 22 | #include <sched.h> | |
| 23 | #include <sysdep.h> | |
| 24 | #include <arch/spr_def.h> | |
| 25 | ||
| 26 | ||
| 27 | /* The count of cores horizontally (X dimension) on the chip. */ | |
| 28 | static int chip_width; | |
| 29 | ||
| 30 | /* Read the chip "width" from the /sys filesystem. */ | |
| 31 | static int | |
| 32 | initialize_chip_width (void) | |
| 33 | { | |
| 34 | int w = 0; | |
| 35 | int fd; | |
| 36 | ||
| 37 | fd = __open ("/sys/devices/system/cpu/chip_width", O_RDONLY); | |
| 38 | if (fd >= 0) | |
| 39 | { | |
| 40 | char buf[64]; | |
| 41 | ssize_t n; | |
| 42 | int i; | |
| 43 | ||
| 44 | n = __read (fd, buf, sizeof (buf)); | |
| 45 | __close (fd); | |
| 46 | ||
| 47 | for (i = 0; i < n; ++i) | |
| 48 | { | |
| 49 | if (buf[i] < '0' || buf[i] > '9') | |
| 50 | break; | |
| 51 | w = (w * 10) + (buf[i] - '0'); | |
| 52 | } | |
| 53 | } | |
| 54 | ||
| 55 | /* Store a negative value so we don't try again. */ | |
| 56 | if (w == 0) | |
| 57 | w = -1; | |
| 58 | ||
| 59 | /* Using an atomic idempotent write here makes this thread-safe. */ | |
| 60 | chip_width = w; | |
| 61 | return w; | |
| 62 | } | |
| 63 | ||
| 64 | int | |
| 65 | sched_getcpu (void) | |
| 66 | { | |
| 67 | unsigned int coord; | |
| 68 | int w = chip_width; | |
| 69 | ||
| 70 | if (__builtin_expect (w <= 0, 0)) | |
| 71 | { | |
| 72 | if (w == 0) | |
| 73 | w = initialize_chip_width (); | |
| 74 | if (w < 0) | |
| 75 | { | |
| 76 | unsigned int cpu; | |
| 77 | int r = INLINE_SYSCALL (getcpu, 3, &cpu, NULL, NULL); | |
| 78 | return r == -1 ? r : cpu; | |
| 79 | } | |
| 80 | } | |
| 81 | ||
| 82 | /* Assign 64-bit value to a 32-bit variable to ensure 32-bit multiply. */ | |
| 83 | coord = __insn_mfspr (SPR_TILE_COORD); | |
| 84 | ||
| 85 | /* Extract Y coord from bits 7..10 and X coord from bits 18..21. */ | |
| 86 | return ((coord >> 7) & 0xf) * w + ((coord >> 18) & 0xf); | |
| 87 | } |