[PATCH v5 1/4] powerpc/mm: refactor radix physical page mapping

[Michael Ellerman]

Reza Arbab <arbab at linux.vnet.ibm.com> writes:

> On Mon, Jan 30, 2017 at 07:38:18PM +1100, Michael Ellerman wrote:
>>Doesn't build.
>>
>>In file included from ../include/linux/kernel.h:13:0,
>>                 from ../include/linux/sched.h:17,
>>                 from ../arch/powerpc/mm/pgtable-radix.c:11:
>>../arch/powerpc/mm/pgtable-radix.c: In function ‘create_physical_mapping’:
>>../include/linux/printk.h:299:2: error: ‘mapping_size’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>>  printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
>>  ^~~~~~
>>../arch/powerpc/mm/pgtable-radix.c:123:22: note: ‘mapping_size’ was declared here
>>  unsigned long addr, mapping_size;
>
> Doh. Could you please do the following for now?
>
> -	unsigned long addr, mapping_size;
> +	unsigned long addr, mapping_size = 0;

Thanks.

> I'd like to delay spinning v6 with this until I see any input you might 
> have on the rest of the set.

I don't think I have any at the moment. So I'll just fold the above into
v5.

> And for future reference, how are you ending up with 
> -Werror=maybe-uninitialized? On powerpc/next, with pseries_le_defconfig, 
> I get -Wno-maybe-uninitialized.

By default. Probably you're not getting it because your compiler is too
old. If I'm reading Makefile correctly it's enabled for GCC 4.9 or later:

  KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \
  			$(call cc-disable-warning,maybe-uninitialized,))

I'm using GCC 6.2.0.

cheers