Re: Linux-next-20200302: arm64 build failed

[Mike Rapoport]

On Mon, Mar 02, 2020 at 10:47:27AM +0000, Will Deacon wrote:
> [+Anshuman and Catalin]
> 
> On Mon, Mar 02, 2020 at 01:58:26PM +0530, Naresh Kamboju wrote:
> > Linux-Next 20200302 arm64 build failed due to below errors,
> > Suspecting patch causing this build break.
> > 
> > 87d900aef3e2  arm/arm64: add support for folded p4d page tables
> > 
> > Error log,
> > -------------
> > arch/arm64/mm/mmu.c: In function 'unmap_hotplug_pud_range':
> > include/linux/compiler.h:284:1: error: incompatible type for argument
> > 1 of 'p4d_page_paddr'
> >  ({         \
> >  ^
> > arch/arm64/include/asm/memory.h:270:45: note: in definition of macro
> > '__phys_to_virt'
> >  #define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset))
> >                                              ^
> > arch/arm64/include/asm/pgtable.h:629:42: note: in expansion of macro '__va'
> >  #define pud_offset(dir, addr)  ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> >                                           ^~~~
> > include/linux/compiler.h:293:22: note: in expansion of macro '__READ_ONCE'
> >  #define READ_ONCE(x) __READ_ONCE(x, 1)
> >                       ^~~~~~~~~~~
> > arch/arm64/include/asm/pgtable.h:628:52: note: in expansion of macro 'READ_ONCE'
> >  #define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir)))
> > + pud_index(addr) * sizeof(pud_t))
> >                                                     ^~~~~~~~~
> > arch/arm64/include/asm/pgtable.h:629:47: note: in expansion of macro
> > 'pud_offset_phys'
> >  #define pud_offset(dir, addr)  ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> >                                                ^~~~~~~~~~~~~~~
> > arch/arm64/mm/mmu.c:827:10: note: in expansion of macro 'pud_offset'
> >    pudp = pud_offset(pgdp, addr);
> >           ^~~~~~~~~~
> 
> Looks like we need an implementation of unmap_hotplug_p4d_range() to
> walk the dummy p4d level. Unfortunately, we don't have the folded p4d
> patches in the arm64 tree so we'll either need a common branch or the
> hotplug patches will need to be dropped for the moment.

unmap_hotplug_p4d_range() is easy :)