105 lines
3.0 KiB
Diff
105 lines
3.0 KiB
Diff
Subject: printk-rt-aware.patch
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Wed, 19 Sep 2012 14:50:37 +0200
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/3.10/patches-3.10.4-rt1.tar.xz
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/printk.c | 33 +++++++++++++++++++++++++++++----
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1 file changed, 29 insertions(+), 4 deletions(-)
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Index: linux-stable/kernel/printk.c
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===================================================================
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--- linux-stable.orig/kernel/printk.c
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+++ linux-stable/kernel/printk.c
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@@ -1277,6 +1277,7 @@ static void call_console_drivers(int lev
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if (!console_drivers)
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return;
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+ migrate_disable();
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for_each_console(con) {
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if (exclusive_console && con != exclusive_console)
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continue;
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@@ -1289,6 +1290,7 @@ static void call_console_drivers(int lev
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continue;
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con->write(con, text, len);
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}
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+ migrate_enable();
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}
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/*
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@@ -1348,12 +1350,18 @@ static inline int can_use_console(unsign
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* interrupts disabled. It should return with 'lockbuf_lock'
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* released but interrupts still disabled.
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*/
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-static int console_trylock_for_printk(unsigned int cpu)
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+static int console_trylock_for_printk(unsigned int cpu, unsigned long flags)
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__releases(&logbuf_lock)
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{
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int retval = 0, wake = 0;
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+ int lock = !early_boot_irqs_disabled && !irqs_disabled_flags(flags) &&
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+ (preempt_count() <= 1);
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+#else
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+ int lock = 1;
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+#endif
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- if (console_trylock()) {
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+ if (lock && console_trylock()) {
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retval = 1;
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/*
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@@ -1688,8 +1696,15 @@ asmlinkage int vprintk_emit(int facility
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* The console_trylock_for_printk() function will release 'logbuf_lock'
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* regardless of whether it actually gets the console semaphore or not.
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*/
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- if (console_trylock_for_printk(this_cpu))
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+ if (console_trylock_for_printk(this_cpu, flags)) {
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+#ifndef CONFIG_PREEMPT_RT_FULL
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+ console_unlock();
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+#else
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+ raw_local_irq_restore(flags);
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console_unlock();
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+ raw_local_irq_save(flags);
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+#endif
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+ }
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lockdep_on();
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out_restore_irqs:
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@@ -2043,11 +2058,16 @@ static void console_cont_flush(char *tex
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goto out;
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len = cont_print_text(text, size);
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+#ifndef CONFIG_PREEMPT_RT_FULL
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raw_spin_unlock(&logbuf_lock);
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stop_critical_timings();
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call_console_drivers(cont.level, text, len);
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start_critical_timings();
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local_irq_restore(flags);
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+#else
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+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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+ call_console_drivers(cont.level, text, len);
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+#endif
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return;
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out:
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raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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@@ -2130,12 +2150,17 @@ skip:
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console_idx = log_next(console_idx);
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console_seq++;
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console_prev = msg->flags;
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- raw_spin_unlock(&logbuf_lock);
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+#ifndef CONFIG_PREEMPT_RT_FULL
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+ raw_spin_unlock(&logbuf_lock);
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stop_critical_timings(); /* don't trace print latency */
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call_console_drivers(level, text, len);
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start_critical_timings();
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local_irq_restore(flags);
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+#else
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+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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+ call_console_drivers(level, text, len);
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+#endif
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}
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console_locked = 0;
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mutex_release(&console_lock_dep_map, 1, _RET_IP_);
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