| /* Copyright (C) 2012-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <stddef.h> |
| #include <fcntl.h> |
| #include <unistd.h> |
| #include <sched.h> |
| #include <sysdep.h> |
| #include <arch/spr_def.h> |
| |
| |
| /* The count of cores horizontally (X dimension) on the chip. */ |
| static int chip_width; |
| |
| /* Read the chip "width" from the /sys filesystem. */ |
| static int |
| initialize_chip_width (void) |
| { |
| int w = 0; |
| int fd; |
| |
| fd = __open ("/sys/devices/system/cpu/chip_width", O_RDONLY); |
| if (fd >= 0) |
| { |
| char buf[64]; |
| ssize_t n; |
| int i; |
| |
| n = __read (fd, buf, sizeof (buf)); |
| __close (fd); |
| |
| for (i = 0; i < n; ++i) |
| { |
| if (buf[i] < '0' || buf[i] > '9') |
| break; |
| w = (w * 10) + (buf[i] - '0'); |
| } |
| } |
| |
| /* Store a negative value so we don't try again. */ |
| if (w == 0) |
| w = -1; |
| |
| /* Using an atomic idempotent write here makes this thread-safe. */ |
| chip_width = w; |
| return w; |
| } |
| |
| int |
| sched_getcpu (void) |
| { |
| unsigned int coord; |
| int w = chip_width; |
| |
| if (__builtin_expect (w <= 0, 0)) |
| { |
| if (w == 0) |
| w = initialize_chip_width (); |
| if (w < 0) |
| { |
| unsigned int cpu; |
| int r = INLINE_SYSCALL (getcpu, 3, &cpu, NULL, NULL); |
| return r == -1 ? r : cpu; |
| } |
| } |
| |
| /* Assign 64-bit value to a 32-bit variable to ensure 32-bit multiply. */ |
| coord = __insn_mfspr (SPR_TILE_COORD); |
| |
| /* Extract Y coord from bits 7..10 and X coord from bits 18..21. */ |
| return ((coord >> 7) & 0xf) * w + ((coord >> 18) & 0xf); |
| } |