[PATCH] ARM: Add BUG_ON when hlt counter is wrongly used
fwu at marvell.com
Fri Sep 28 20:45:36 EDT 2012
On 09/29/2012 03:45 AM, Nicolas Pitre wrote:
> On Fri, 28 Sep 2012, Fan Wu wrote:
>> From: fwu <fwu at marvell.com>
>> 1. On ARM platform, "nohlt" can be used to prevent core from idle
>> process, returning immediately.
>> 2. There are two interfaces, exported for other modules, named
>> "disable_hlt" and "enable_hlt" are used to enable/disable the
>> cpuidle mechanism by increasing/decreasing "hlt_counter".
>> Disable_hlt and enable_hlt are paired operation,
>> when you first call disable_hlt and then enable_hlt, the
>> semantics are right.
>> 3. There is no obvious constraint to prevent user(driver/module)
>> code to prevent the case that enable_hlt is ahead of disable_hlt,
>> which is a fatal operation on kernel state change from user,
>> and there is no any WARNING or notification if the case happens
>> in current kernel code.
>> This patch aims to report BUG when the case happens, just like
>> what the kernel do when enable_irq is ahead of disable_irq.
>> Signed-off-by: fwu <fwu at marvell.com>
>> Signed-off-by: YiLu Mao <ylmao at marvell.com>
>> Signed-off-by: Ning Jiang <ning.jiang at marvell.com>
> This looks sensible to me.
> Acked-by: Nicolas Pitre <nico at linaro.org>
>> Change-Id: Iddacf45aec012bb663e130801727b4eb3d11436b
> Please don't forget to strip that when submitting your patch to
> Russell's patch system.
>> arch/arm/kernel/process.c | 1 +
>> 1 files changed, 1 insertions(+), 0 deletions(-)
>> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
>> index 693b744..5bbd3be 100644
>> --- a/arch/arm/kernel/process.c
>> +++ b/arch/arm/kernel/process.c
>> @@ -70,6 +70,7 @@ EXPORT_SYMBOL(disable_hlt);
>> void enable_hlt(void)
>> + BUG_ON(hlt_counter < 0)
Thanks a lot for reviewing the patch.
I'll remove that in the new patch version.
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