From f21afc25f9ed45b8ffe200d0f071b0caec3ed2ef Mon Sep 17 00:00:00 2001 From: David Daney 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 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 Cc: Ralf Baechle Cc: Andrew Morton Signed-off-by: Linus Torvalds --- 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 #include #include +#include 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 -- 2.20.1