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Diffstat (limited to '')
| -rw-r--r-- | arch/parisc/lib/debuglocks.c | 277 |
1 files changed, 0 insertions, 277 deletions
diff --git a/arch/parisc/lib/debuglocks.c b/arch/parisc/lib/debuglocks.c deleted file mode 100644 index 1b33fe6e5b7a..000000000000 --- a/arch/parisc/lib/debuglocks.c +++ /dev/null @@ -1,277 +0,0 @@ -/* - * Debugging versions of SMP locking primitives. - * - * Copyright (C) 2004 Thibaut VARENE <varenet@parisc-linux.org> - * - * Some code stollen from alpha & sparc64 ;) - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program 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 General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * - * We use pdc_printf() throughout the file for all output messages, to avoid - * losing messages because of disabled interrupts. Since we're using these - * messages for debugging purposes, it makes sense not to send them to the - * linux console. - */ - - -#include <linux/config.h> -#include <linux/kernel.h> -#include <linux/sched.h> -#include <linux/spinlock.h> -#include <linux/hardirq.h> /* in_interrupt() */ -#include <asm/system.h> -#include <asm/hardirq.h> /* in_interrupt() */ -#include <asm/pdc.h> - -#undef INIT_STUCK -#define INIT_STUCK 1L << 30 - -#ifdef CONFIG_DEBUG_SPINLOCK - - -void _dbg_spin_lock(spinlock_t * lock, const char *base_file, int line_no) -{ - volatile unsigned int *a; - long stuck = INIT_STUCK; - void *inline_pc = __builtin_return_address(0); - unsigned long started = jiffies; - int printed = 0; - int cpu = smp_processor_id(); - -try_again: - - /* Do the actual locking */ - /* <T-Bone> ggg: we can't get stuck on the outter loop? - * <ggg> T-Bone: We can hit the outer loop - * alot if multiple CPUs are constantly racing for a lock - * and the backplane is NOT fair about which CPU sees - * the update first. But it won't hang since every failed - * attempt will drop us back into the inner loop and - * decrement `stuck'. - * <ggg> K-class and some of the others are NOT fair in the HW - * implementation so we could see false positives. - * But fixing the lock contention is easier than - * fixing the HW to be fair. - * <tausq> __ldcw() returns 1 if we get the lock; otherwise we - * spin until the value of the lock changes, or we time out. - */ - mb(); - a = __ldcw_align(lock); - while (stuck && (__ldcw(a) == 0)) - while ((*a == 0) && --stuck); - mb(); - - if (unlikely(stuck <= 0)) { - pdc_printf( - "%s:%d: spin_lock(%s/%p) stuck in %s at %p(%d)" - " owned by %s:%d in %s at %p(%d)\n", - base_file, line_no, lock->module, lock, - current->comm, inline_pc, cpu, - lock->bfile, lock->bline, lock->task->comm, - lock->previous, lock->oncpu); - stuck = INIT_STUCK; - printed = 1; - goto try_again; - } - - /* Exiting. Got the lock. */ - lock->oncpu = cpu; - lock->previous = inline_pc; - lock->task = current; - lock->bfile = (char *)base_file; - lock->bline = line_no; - - if (unlikely(printed)) { - pdc_printf( - "%s:%d: spin_lock grabbed in %s at %p(%d) %ld ticks\n", - base_file, line_no, current->comm, inline_pc, - cpu, jiffies - started); - } -} - -void _dbg_spin_unlock(spinlock_t * lock, const char *base_file, int line_no) -{ - CHECK_LOCK(lock); - volatile unsigned int *a; - mb(); - a = __ldcw_align(lock); - if (unlikely((*a != 0) && lock->babble)) { - lock->babble--; - pdc_printf( - "%s:%d: spin_unlock(%s:%p) not locked\n", - base_file, line_no, lock->module, lock); - } - *a = 1; - mb(); -} - -int _dbg_spin_trylock(spinlock_t * lock, const char *base_file, int line_no) -{ - int ret; - volatile unsigned int *a; - mb(); - a = __ldcw_align(lock); - ret = (__ldcw(a) != 0); - mb(); - if (ret) { - lock->oncpu = smp_processor_id(); - lock->previous = __builtin_return_address(0); - lock->task = current; - } else { - lock->bfile = (char *)base_file; - lock->bline = line_no; - } - return ret; -} - -#endif /* CONFIG_DEBUG_SPINLOCK */ - -#ifdef CONFIG_DEBUG_RWLOCK - -/* Interrupts trouble detailed explanation, thx Grant: - * - * o writer (wants to modify data) attempts to acquire the rwlock - * o He gets the write lock. - * o Interupts are still enabled, we take an interrupt with the - * write still holding the lock. - * o interrupt handler tries to acquire the rwlock for read. - * o deadlock since the writer can't release it at this point. - * - * In general, any use of spinlocks that competes between "base" - * level and interrupt level code will risk deadlock. Interrupts - * need to be disabled in the base level routines to avoid it. - * Or more precisely, only the IRQ the base level routine - * is competing with for the lock. But it's more efficient/faster - * to just disable all interrupts on that CPU to guarantee - * once it gets the lock it can release it quickly too. - */ - -void _dbg_write_lock(rwlock_t *rw, const char *bfile, int bline) -{ - void *inline_pc = __builtin_return_address(0); - unsigned long started = jiffies; - long stuck = INIT_STUCK; - int printed = 0; - int cpu = smp_processor_id(); - - if(unlikely(in_interrupt())) { /* acquiring write lock in interrupt context, bad idea */ - pdc_printf("write_lock caller: %s:%d, IRQs enabled,\n", bfile, bline); - BUG(); - } - - /* Note: if interrupts are disabled (which is most likely), the printk - will never show on the console. We might need a polling method to flush - the dmesg buffer anyhow. */ - -retry: - _raw_spin_lock(&rw->lock); - - if(rw->counter != 0) { - /* this basically never happens */ - _raw_spin_unlock(&rw->lock); - - stuck--; - if ((unlikely(stuck <= 0)) && (rw->counter < 0)) { - pdc_printf( - "%s:%d: write_lock stuck on writer" - " in %s at %p(%d) %ld ticks\n", - bfile, bline, current->comm, inline_pc, - cpu, jiffies - started); - stuck = INIT_STUCK; - printed = 1; - } - else if (unlikely(stuck <= 0)) { - pdc_printf( - "%s:%d: write_lock stuck on reader" - " in %s at %p(%d) %ld ticks\n", - bfile, bline, current->comm, inline_pc, - cpu, jiffies - started); - stuck = INIT_STUCK; - printed = 1; - } - - while(rw->counter != 0); - - goto retry; - } - - /* got it. now leave without unlocking */ - rw->counter = -1; /* remember we are locked */ - - if (unlikely(printed)) { - pdc_printf( - "%s:%d: write_lock grabbed in %s at %p(%d) %ld ticks\n", - bfile, bline, current->comm, inline_pc, - cpu, jiffies - started); - } -} - -int _dbg_write_trylock(rwlock_t *rw, const char *bfile, int bline) -{ -#if 0 - void *inline_pc = __builtin_return_address(0); - int cpu = smp_processor_id(); -#endif - - if(unlikely(in_interrupt())) { /* acquiring write lock in interrupt context, bad idea */ - pdc_printf("write_lock caller: %s:%d, IRQs enabled,\n", bfile, bline); - BUG(); - } - - /* Note: if interrupts are disabled (which is most likely), the printk - will never show on the console. We might need a polling method to flush - the dmesg buffer anyhow. */ - - _raw_spin_lock(&rw->lock); - - if(rw->counter != 0) { - /* this basically never happens */ - _raw_spin_unlock(&rw->lock); - return 0; - } - - /* got it. now leave without unlocking */ - rw->counter = -1; /* remember we are locked */ -#if 0 - pdc_printf("%s:%d: try write_lock grabbed in %s at %p(%d)\n", - bfile, bline, current->comm, inline_pc, cpu); -#endif - return 1; -} - -void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline) -{ -#if 0 - void *inline_pc = __builtin_return_address(0); - unsigned long started = jiffies; - int cpu = smp_processor_id(); -#endif - unsigned long flags; - - local_irq_save(flags); - _raw_spin_lock(&rw->lock); - - rw->counter++; -#if 0 - pdc_printf( - "%s:%d: read_lock grabbed in %s at %p(%d) %ld ticks\n", - bfile, bline, current->comm, inline_pc, - cpu, jiffies - started); -#endif - _raw_spin_unlock(&rw->lock); - local_irq_restore(flags); -} - -#endif /* CONFIG_DEBUG_RWLOCK */ |