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71 lines
1.5 KiB
C
71 lines
1.5 KiB
C
// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include "brick_say.h"
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/////////////////////////////////////////////////////////////////////
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// messaging
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#ifdef CONFIG_DEBUG_KERNEL
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#include <linux/preempt.h>
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#include <linux/hardirq.h>
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static char say_buf[PAGE_SIZE * 8] = {};
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static int say_index = 0;
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static int dump_max = 5;
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/* This is racy.
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* But we don't want to contend the CPUs neither by global locks nor by RCU.
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* We just emit some limited kind of "garbage" upon overflow or races.
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* This kind of informational garbage for humans will not hurt correctness
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* of the real logic in any way, we just take it into account.
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*/
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void say_mark(void)
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{
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if (say_buf[0]) {
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printk("# %s", say_buf);
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say_buf[0] = '\0';
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say_index = 0;
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}
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}
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EXPORT_SYMBOL(say_mark);
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void say(const char *fmt, ...)
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{
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va_list args;
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if (preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK | HARDIRQ_MASK)) {
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va_start(args, fmt);
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say_index += vsnprintf(say_buf + say_index, sizeof(say_buf) - say_index, fmt, args);
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va_end(args);
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if (unlikely(say_index >= sizeof(say_buf))) {
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say_index = sizeof(say_buf);
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say_buf[say_index-1] = '\0';
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}
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} else {
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say_mark();
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va_start(args, fmt);
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vprintk(fmt, args);
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va_end(args);
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}
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}
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EXPORT_SYMBOL(say);
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void brick_dump_stack(void)
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{
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if (dump_max > 0) {
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dump_max--; // racy, but does no harm
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dump_stack();
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}
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}
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EXPORT_SYMBOL(brick_dump_stack);
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#endif
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