paul@181 | 1 | /* |
paul@181 | 2 | * Semaphore utilities. |
paul@181 | 3 | * |
paul@181 | 4 | * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk> |
paul@181 | 5 | * |
paul@181 | 6 | * This program is free software; you can redistribute it and/or |
paul@181 | 7 | * modify it under the terms of the GNU General Public License as |
paul@181 | 8 | * published by the Free Software Foundation; either version 2 of |
paul@181 | 9 | * the License, or (at your option) any later version. |
paul@181 | 10 | * |
paul@181 | 11 | * This program is distributed in the hope that it will be useful, |
paul@181 | 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
paul@181 | 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
paul@181 | 14 | * GNU General Public License for more details. |
paul@181 | 15 | * |
paul@181 | 16 | * You should have received a copy of the GNU General Public License |
paul@181 | 17 | * along with this program; if not, write to the Free Software |
paul@181 | 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, |
paul@181 | 19 | * Boston, MA 02110-1301, USA |
paul@181 | 20 | */ |
paul@181 | 21 | |
paul@181 | 22 | #include <l4/sys/err.h> |
paul@181 | 23 | #include <l4/sys/semaphore.h> |
paul@181 | 24 | |
paul@181 | 25 | #include "semaphore.h" |
paul@181 | 26 | |
paul@181 | 27 | |
paul@181 | 28 | |
paul@181 | 29 | /* Obtain control of a semaphore. */ |
paul@181 | 30 | |
paul@181 | 31 | long ipc_semaphore_down(l4_cap_idx_t semaphore) |
paul@181 | 32 | { |
paul@181 | 33 | long err; |
paul@181 | 34 | |
paul@181 | 35 | if (l4_is_valid_cap(semaphore)) |
paul@181 | 36 | { |
paul@181 | 37 | do |
paul@181 | 38 | { |
paul@181 | 39 | /* Since l4_irq_trigger is a "send-only" operation, l4_error is not |
paul@181 | 40 | appropriate. */ |
paul@181 | 41 | |
paul@181 | 42 | err = l4_ipc_error(l4_semaphore_down(semaphore, L4_IPC_NEVER), l4_utcb()); |
paul@181 | 43 | |
paul@181 | 44 | /* Handle EAGAIN ("Resource temporarily unavailable") by just retrying. */ |
paul@181 | 45 | |
paul@181 | 46 | if (err) |
paul@181 | 47 | { |
paul@181 | 48 | if (err == -L4_EAGAIN) |
paul@181 | 49 | continue; |
paul@181 | 50 | else |
paul@181 | 51 | return err; |
paul@181 | 52 | } |
paul@181 | 53 | } |
paul@181 | 54 | while (0); |
paul@181 | 55 | } |
paul@181 | 56 | |
paul@181 | 57 | return L4_EOK; |
paul@181 | 58 | } |
paul@181 | 59 | |
paul@181 | 60 | /* Relinquish control of a semaphore. */ |
paul@181 | 61 | |
paul@181 | 62 | long ipc_semaphore_up(l4_cap_idx_t semaphore) |
paul@181 | 63 | { |
paul@181 | 64 | long err; |
paul@181 | 65 | |
paul@181 | 66 | if (l4_is_valid_cap(semaphore)) |
paul@181 | 67 | { |
paul@181 | 68 | do |
paul@181 | 69 | { |
paul@181 | 70 | /* Since l4_irq_trigger is a "send-only" operation, l4_error is not |
paul@181 | 71 | appropriate. */ |
paul@181 | 72 | |
paul@181 | 73 | err = l4_ipc_error(l4_semaphore_up(semaphore), l4_utcb()); |
paul@181 | 74 | |
paul@181 | 75 | /* Handle EAGAIN ("Resource temporarily unavailable") by just retrying. */ |
paul@181 | 76 | |
paul@181 | 77 | if (err) |
paul@181 | 78 | { |
paul@181 | 79 | if (err == -L4_EAGAIN) |
paul@181 | 80 | continue; |
paul@181 | 81 | else |
paul@181 | 82 | return err; |
paul@181 | 83 | } |
paul@181 | 84 | } |
paul@181 | 85 | while (0); |
paul@181 | 86 | } |
paul@181 | 87 | |
paul@181 | 88 | return L4_EOK; |
paul@181 | 89 | } |
paul@181 | 90 | |
paul@181 | 91 | // vim: tabstop=2 expandtab shiftwidth=2 |