[PATCH 10/12] kexec: arrange for paddr_vmcoreinfo_note() to return phys_addr_t

[Pratyush Anand]

On Fri, Apr 29, 2016 at 11:36 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Fri, Apr 29, 2016 at 08:36:43PM +0530, Pratyush Anand wrote:
>> On Thu, Apr 28, 2016 at 2:58 PM, Russell King
>> <rmk+kernel at arm.linux.org.uk> wrote:
>> > diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
>> > index 152da4a48867..9f1920d2d0c6 100644
>> > --- a/kernel/ksysfs.c
>> > +++ b/kernel/ksysfs.c
>> > @@ -128,8 +128,8 @@ KERNEL_ATTR_RW(kexec_crash_size);
>> >  static ssize_t vmcoreinfo_show(struct kobject *kobj,
>> >                                struct kobj_attribute *attr, char *buf)
>> >  {
>> > -       return sprintf(buf, "%lx %x\n",
>> > -                      paddr_vmcoreinfo_note(),
>> > +       phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
>> > +       return sprintf(buf, "%pa %x\n", &vmcore_base,
>>
>> Why do we pass &vmcore_base? Shouldn't it be vmcore_base?
>
> You seem to not know what the "%pa" format string means.

Apologies, Yes, yes.. it was my negligence.

>
> %p always takes a _pointer_ as per C standard, so the printf argument
> must be a pointer.  However, the kernel format strings are extended
> with additional suffixes - in this case 'a', which means that we want
> to print the contents of a _pointer_ to a phys_addr_t.
>
> Full details in Documentation/printk-formats.txt in the kernel.

Thanks for explaining :-)