From e3e12f52b214121840b44c91de5b3e5af5d3eb84 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 06 Nov 2023 03:04:41 +0000
Subject: [PATCH] rk3568 rt init
---
kernel/kernel/printk/printk.c | 157 ++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 134 insertions(+), 23 deletions(-)
diff --git a/kernel/kernel/printk/printk.c b/kernel/kernel/printk/printk.c
index a1f5484..611c7c9 100644
--- a/kernel/kernel/printk/printk.c
+++ b/kernel/kernel/printk/printk.c
@@ -429,6 +429,65 @@
printk_safe_exit_irqrestore(flags); \
} while (0)
+#ifdef CONFIG_EARLY_PRINTK
+struct console *early_console;
+
+static void early_vprintk(const char *fmt, va_list ap)
+{
+ if (early_console) {
+ char buf[512];
+ int n = vscnprintf(buf, sizeof(buf), fmt, ap);
+
+ early_console->write(early_console, buf, n);
+ }
+}
+
+asmlinkage void early_printk(const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ early_vprintk(fmt, ap);
+ va_end(ap);
+}
+
+/*
+ * This is independent of any log levels - a global
+ * kill switch that turns off all of printk.
+ *
+ * Used by the NMI watchdog if early-printk is enabled.
+ */
+static bool __read_mostly printk_killswitch;
+
+static int __init force_early_printk_setup(char *str)
+{
+ printk_killswitch = true;
+ return 0;
+}
+early_param("force_early_printk", force_early_printk_setup);
+
+void printk_kill(void)
+{
+ printk_killswitch = true;
+}
+
+#ifdef CONFIG_PRINTK
+static int forced_early_printk(const char *fmt, va_list ap)
+{
+ if (!printk_killswitch)
+ return 0;
+ early_vprintk(fmt, ap);
+ return 1;
+}
+#endif
+
+#else
+static inline int forced_early_printk(const char *fmt, va_list ap)
+{
+ return 0;
+}
+#endif
+
#ifdef CONFIG_PRINTK
DECLARE_WAIT_QUEUE_HEAD(log_wait);
/* the next printk record to read by syslog(READ) or /proc/kmsg */
@@ -1517,12 +1576,23 @@
u64 next_seq;
u64 seq;
u32 idx;
+ int attempts = 0;
+ int num_msg;
text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
if (!text)
return -ENOMEM;
logbuf_lock_irq();
+
+try_again:
+ attempts++;
+ if (attempts > 10) {
+ len = -EBUSY;
+ goto out;
+ }
+ num_msg = 0;
+
/*
* Find first record that fits, including all following records,
* into the user-provided buffer for this dump.
@@ -1535,6 +1605,14 @@
len += msg_print_text(msg, true, NULL, 0);
idx = log_next(idx);
seq++;
+ num_msg++;
+ if (num_msg > 5) {
+ num_msg = 0;
+ logbuf_unlock_irq();
+ logbuf_lock_irq();
+ if (clear_seq < log_first_seq)
+ goto try_again;
+ }
}
/* move first record forward until length fits into the buffer */
@@ -1546,6 +1624,14 @@
len -= msg_print_text(msg, true, NULL, 0);
idx = log_next(idx);
seq++;
+ num_msg++;
+ if (num_msg > 5) {
+ num_msg = 0;
+ logbuf_unlock_irq();
+ logbuf_lock_irq();
+ if (clear_seq < log_first_seq)
+ goto try_again;
+ }
}
/* last message fitting into this dump */
@@ -1583,6 +1669,7 @@
clear_seq = log_next_seq;
clear_idx = log_next_idx;
}
+out:
logbuf_unlock_irq();
kfree(text);
@@ -1714,6 +1801,7 @@
return do_syslog(type, buf, len, SYSLOG_FROM_READER);
}
+#ifndef CONFIG_PREEMPT_RT_FULL
/*
* Special console_lock variants that help to reduce the risk of soft-lockups.
* They allow to pass console_lock to another printk() call using a busy wait.
@@ -1854,6 +1942,15 @@
return 1;
}
+#else
+
+static int console_trylock_spinning(void)
+{
+ return console_trylock();
+}
+
+#endif
+
/*
* Call the console drivers, asking them to write out
* log_buf[start] to log_buf[end - 1].
@@ -1872,6 +1969,12 @@
if (!console_drivers)
return;
+ if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) {
+ if (in_irq() || in_nmi())
+ return;
+ }
+
+ migrate_disable();
for_each_console(con) {
if (exclusive_console && con != exclusive_console)
continue;
@@ -1887,6 +1990,7 @@
else
con->write(con, text, len);
}
+ migrate_enable();
}
int printk_delay_msec __read_mostly;
@@ -2057,6 +2161,13 @@
unsigned long flags;
u64 curr_log_seq;
+ /*
+ * Fall back to early_printk if a debugging subsystem has
+ * killed printk output
+ */
+ if (unlikely(forced_early_printk(fmt, args)))
+ return 1;
+
if (level == LOGLEVEL_SCHED) {
level = LOGLEVEL_DEFAULT;
in_sched = true;
@@ -2074,20 +2185,30 @@
/* If called from the scheduler, we can not call up(). */
if (!in_sched && pending_output) {
+ int may_trylock = 1;
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+ /*
+ * we can't take a sleeping lock with IRQs or preeption disabled
+ * so we can't print in these contexts
+ */
+ if (!(preempt_count() == 0 && !irqs_disabled()))
+ may_trylock = 0;
+#endif
/*
* Disable preemption to avoid being preempted while holding
* console_sem which would prevent anyone from printing to
* console
*/
- preempt_disable();
+ migrate_disable();
/*
* Try to acquire and then immediately release the console
* semaphore. The release will print out buffers and wake up
* /dev/kmsg and syslog() users.
*/
- if (console_trylock_spinning())
+ if (may_trylock && console_trylock_spinning())
console_unlock();
- preempt_enable();
+ migrate_enable();
}
if (pending_output)
@@ -2200,26 +2321,6 @@
static bool suppress_message_printing(int level) { return false; }
#endif /* CONFIG_PRINTK */
-
-#ifdef CONFIG_EARLY_PRINTK
-struct console *early_console;
-
-asmlinkage __visible void early_printk(const char *fmt, ...)
-{
- va_list ap;
- char buf[512];
- int n;
-
- if (!early_console)
- return;
-
- va_start(ap, fmt);
- n = vscnprintf(buf, sizeof(buf), fmt, ap);
- va_end(ap);
-
- early_console->write(early_console, buf, n);
-}
-#endif
static int __add_preferred_console(char *name, int idx, char *options,
char *brl_options)
@@ -2579,6 +2680,10 @@
console_seq++;
raw_spin_unlock(&logbuf_lock);
+#ifdef CONFIG_PREEMPT_RT_FULL
+ printk_safe_exit_irqrestore(flags);
+ call_console_drivers(ext_text, ext_len, text, len);
+#else
/*
* While actively printing out messages, if another printk()
* were to occur on another CPU, it may wait for this one to
@@ -2601,6 +2706,7 @@
}
printk_safe_exit_irqrestore(flags);
+#endif
if (do_cond_resched)
cond_resched();
@@ -2648,6 +2754,11 @@
{
struct console *c;
+ if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) {
+ if (in_irq() || in_nmi())
+ return;
+ }
+
/*
* console_unblank can no longer be called in interrupt context unless
* oops_in_progress is set to 1..
--
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