From f21afc25f9ed45b8ffe200d0f071b0caec3ed2ef Mon Sep 17 00:00:00 2001
From: David Daney <david.daney@cavium.com>
Date: Fri, 14 Jun 2013 11:13:59 -0700
Subject: [PATCH] smp.h: Use local_irq_{save,restore}() in !SMP version of
on_each_cpu().
Thanks to commit f91eb62f71b3 ("init: scream bloody murder if interrupts
are enabled too early"), "bloody murder" is now being screamed.
With a MIPS OCTEON config, we use on_each_cpu() in our
irq_chip.irq_bus_sync_unlock() function. This gets called in early as a
result of the time_init() call. Because the !SMP version of
on_each_cpu() unconditionally enables irqs, we get:
WARNING: at init/main.c:560 start_kernel+0x250/0x410()
Interrupts were enabled early
CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0-rc5-Cavium-Octeon+ #801
Call Trace:
show_stack+0x68/0x80
warn_slowpath_common+0x78/0xb0
warn_slowpath_fmt+0x38/0x48
start_kernel+0x250/0x410
Suggested fix: Do what we already do in the SMP version of
on_each_cpu(), and use local_irq_save/local_irq_restore. Because we
need a flags variable, make it a static inline to avoid name space
issues.
[ Change from v1: Convert on_each_cpu to a static inline function, add
#include <linux/irqflags.h> to avoid build breakage on some files.
on_each_cpu_mask() and on_each_cpu_cond() suffer the same problem as
on_each_cpu(), but they are not causing !SMP bugs for me, so I will
defer changing them to a less urgent patch. ]
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/smp.h | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/include/linux/smp.h b/include/linux/smp.h
index e6564c1dc552..c8488763277f 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -11,6 +11,7 @@
#include <linux/list.h>
#include <linux/cpumask.h>
#include <linux/init.h>
+#include <linux/irqflags.h>
extern void cpu_idle(void);
@@ -139,13 +140,17 @@ static inline int up_smp_call_function(smp_call_func_t func, void *info)
}
#define smp_call_function(func, info, wait) \
(up_smp_call_function(func, info))
-#define on_each_cpu(func,info,wait) \
- ({ \
- local_irq_disable(); \
- func(info); \
- local_irq_enable(); \
- 0; \
- })
+
+static inline int on_each_cpu(smp_call_func_t func, void *info, int wait)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ func(info);
+ local_irq_restore(flags);
+ return 0;
+}
+
/*
* Note we still need to test the mask even for UP
* because we actually can get an empty mask from