| /* Copyright 2013-2014 IBM Corp. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
| * implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <skiboot.h> |
| #include <lock.h> |
| #include <assert.h> |
| #include <processor.h> |
| #include <cpu.h> |
| #include <console.h> |
| |
| /* Set to bust locks. Note, this is initialized to true because our |
| * lock debugging code is not going to work until we have the per |
| * CPU data initialized |
| */ |
| bool bust_locks = true; |
| |
| #ifdef DEBUG_LOCKS |
| |
| static void lock_error(struct lock *l, const char *reason, uint16_t err) |
| { |
| bust_locks = true; |
| |
| fprintf(stderr, "LOCK ERROR: %s @%p (state: 0x%016lx)\n", |
| reason, l, l->lock_val); |
| op_display(OP_FATAL, OP_MOD_LOCK, err); |
| |
| abort(); |
| } |
| |
| static void lock_check(struct lock *l) |
| { |
| if ((l->lock_val & 1) && (l->lock_val >> 32) == this_cpu()->pir) |
| lock_error(l, "Invalid recursive lock", 0); |
| } |
| |
| static void unlock_check(struct lock *l) |
| { |
| if (!(l->lock_val & 1)) |
| lock_error(l, "Unlocking unlocked lock", 1); |
| |
| if ((l->lock_val >> 32) != this_cpu()->pir) |
| lock_error(l, "Unlocked non-owned lock", 2); |
| |
| if (l->in_con_path && this_cpu()->con_suspend == 0) |
| lock_error(l, "Unlock con lock with console not suspended", 3); |
| |
| if (this_cpu()->lock_depth == 0) |
| lock_error(l, "Releasing lock with 0 depth", 4); |
| } |
| |
| #else |
| static inline void lock_check(struct lock *l) { }; |
| static inline void unlock_check(struct lock *l) { }; |
| #endif /* DEBUG_LOCKS */ |
| |
| bool lock_held_by_me(struct lock *l) |
| { |
| uint64_t pir64 = this_cpu()->pir; |
| |
| return l->lock_val == ((pir64 << 32) | 1); |
| } |
| |
| bool try_lock(struct lock *l) |
| { |
| if (__try_lock(l)) { |
| if (l->in_con_path) |
| this_cpu()->con_suspend++; |
| this_cpu()->lock_depth++; |
| return true; |
| } |
| return false; |
| } |
| |
| void lock(struct lock *l) |
| { |
| if (bust_locks) |
| return; |
| |
| lock_check(l); |
| for (;;) { |
| if (try_lock(l)) |
| break; |
| smt_lowest(); |
| while (l->lock_val) |
| barrier(); |
| smt_medium(); |
| } |
| } |
| |
| void unlock(struct lock *l) |
| { |
| struct cpu_thread *cpu = this_cpu(); |
| |
| if (bust_locks) |
| return; |
| |
| unlock_check(l); |
| |
| lwsync(); |
| this_cpu()->lock_depth--; |
| l->lock_val = 0; |
| |
| /* WARNING: On fast reboot, we can be reset right at that |
| * point, so the reset_lock in there cannot be in the con path |
| */ |
| if (l->in_con_path) { |
| cpu->con_suspend--; |
| if (cpu->con_suspend == 0 && cpu->con_need_flush) |
| flush_console(); |
| } |
| } |
| |
| bool lock_recursive(struct lock *l) |
| { |
| if (bust_locks) |
| return false; |
| |
| if (lock_held_by_me(l)) |
| return false; |
| |
| lock(l); |
| return true; |
| } |
| |
| void init_locks(void) |
| { |
| bust_locks = false; |
| } |