Re: [PATCH] irqchip: gic-v3: Explicitly include linux/io.h

[Ben Zhang]

On Fri, Aug 7, 2015 at 1:40 AM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
> Hi Ben,
>
> On 07/08/15 06:31, Ben Zhang wrote:
>> linux/io.h is needed because the driver uses:
>> readl_relaxed
>> writel_relaxed
>> writeq_relaxed
>> readq_relaxed
>> iounmap
>>
>> The header was implicitly included by an unrelated
>> commit 332fd7c4fef5
>> ("genirq: Generic chip: Change irq_reg_{readl,writel} arguments")
>> from the path below:
>> include/linux/io.h
>> include/linux/irq.h
>> include/linux/of_irq.h
>> drivers/irqchip/irq-gic-v3.c
>>
>> Signed-off-by: Ben Zhang <benzh@xxxxxxxxxxxx>
>> ---
>>  drivers/irqchip/irq-gic-v3.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
>> index e406bc5..3350b8d 100644
>> --- a/drivers/irqchip/irq-gic-v3.c
>> +++ b/drivers/irqchip/irq-gic-v3.c
>> @@ -19,6 +19,7 @@
>>  #include <linux/cpu_pm.h>
>>  #include <linux/delay.h>
>>  #include <linux/interrupt.h>
>> +#include <linux/io.h>
>>  #include <linux/of.h>
>>  #include <linux/of_address.h>
>>  #include <linux/of_irq.h>
>>
>
> This seems valid, but out of curiosity: Has this triggered any
> observable build failure? Or is that something you found by inspection?
>
> Thanks,
>
>         M.
> --
> Jazz is not dead. It just smells funny...


Hi Marc,

We have seen a build failure on the v3.18-based kernel for ChromeOS.
After cherry-picking commit 74d23cc704d1 ("time: move the
timecounter/cyclecounter code into its own file.") into the kernel,
irq-gic-v3 build is broken:

/mnt/host/source/src/third_party/kernel/v3.18/drivers/irqchip/irq-gic-v3.c:
In function 'gic_do_wait_for_rwp':
/mnt/host/source/src/third_party/kernel/v3.18/drivers/irqchip/irq-gic-v3.c:84:2:
error: implicit declaration of function 'readl_relaxed'
[-Werror=implicit-function-declaration]
  while (readl_relaxed(base + GICD_CTLR) & GICD_CTLR_RWP) {
  ^
...

The timecounter patch removes #include <linux/clocksource.h> in
include/clocksource/arm_arch_timer.h, and breaks all include paths to
the arm64 io.h header, e.g.
arch/arm64/include/asm/io.h
include/linux/clocksource.h
include/clocksource/arm_arch_timer.h
arch/arm64/include/asm/arch_timer.h
arch/arm64/include/asm/timex.h
include/linux/timex.h
include/linux/sched.h
arch/arm64/include/asm/compat.h
arch/arm64/include/asm/stat.h
include/linux/stat.h
include/linux/sysfs.h
include/linux/kobject.h
include/linux/device.h
include/linux/node.h
include/linux/cpu.h
drivers/irqchip/irq-gic-v3.c

Mainline build is fine because commit 332fd7c4fef5("genirq: Generic
chip: Change irq_reg_{readl,writel} arguments") landed before the
timecounter patch, and it creates a new include path to the io.h
header:
arch/arm64/include/asm/io.h
include/linux/io.h
include/linux/irq.h
include/linux/of_irq.h
drivers/irqchip/irq-gic-v3.c

Thanks,
Ben
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