diff options
Diffstat (limited to 'kernel/debug/kdb/kdb_io.c')
| -rw-r--r-- | kernel/debug/kdb/kdb_io.c | 30 |
1 files changed, 13 insertions, 17 deletions
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 46f477bebe0c..daa76154fb1b 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -555,16 +555,16 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) int colcount; int logging, saved_loglevel = 0; int saved_trap_printk; - int got_printf_lock = 0; int retlen = 0; int fnd, len; + int this_cpu, old_cpu; + static int kdb_printf_cpu = -1; char *cp, *cp2, *cphold = NULL, replaced_byte = ' '; char *moreprompt = "more> "; struct console *c = console_drivers; - static DEFINE_SPINLOCK(kdb_printf_lock); unsigned long uninitialized_var(flags); - preempt_disable(); + local_irq_save(flags); saved_trap_printk = kdb_trap_printk; kdb_trap_printk = 0; @@ -572,12 +572,13 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) * But if any cpu goes recursive in kdb, just print the output, * even if it is interleaved with any other text. */ - if (!KDB_STATE(PRINTF_LOCK)) { - KDB_STATE_SET(PRINTF_LOCK); - spin_lock_irqsave(&kdb_printf_lock, flags); - got_printf_lock = 1; - } else { - __acquire(kdb_printf_lock); + this_cpu = smp_processor_id(); + for (;;) { + old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu); + if (old_cpu == -1 || old_cpu == this_cpu) + break; + + cpu_relax(); } diag = kdbgetintenv("LINES", &linecount); @@ -846,15 +847,10 @@ kdb_print_out: suspend_grep = 0; /* end of what may have been a recursive call */ if (logging) console_loglevel = saved_loglevel; - if (KDB_STATE(PRINTF_LOCK) && got_printf_lock) { - got_printf_lock = 0; - spin_unlock_irqrestore(&kdb_printf_lock, flags); - KDB_STATE_CLEAR(PRINTF_LOCK); - } else { - __release(kdb_printf_lock); - } + /* kdb_printf_cpu locked the code above. */ + smp_store_release(&kdb_printf_cpu, old_cpu); kdb_trap_printk = saved_trap_printk; - preempt_enable(); + local_irq_restore(flags); return retlen; } |