Re: [PATCH] arm64: Add missing linux/bug.h include in asm/pgtable.h

[Catalin Marinas]

On Mon, Dec 14, 2015 at 04:26:48PM +0000, Julien Grall wrote:
> On 14/12/15 16:22, Catalin Marinas wrote:
> > On Mon, Dec 14, 2015 at 04:07:24PM +0000, Julien Grall wrote:
> >> Linux 4.4-rc5 doesn't build for arm64 with CONFIG_XEN=y enabled:
> >>
> >> In file included from linux/arch/arm64/include/asm/pgtable.h:60:0,
> >>                  from linux/arch/arm64/include/../../arm/include/asm/xen/page.h:5,
> >>                  from linux/arch/arm64/include/asm/xen/page.h:1,
> >>                  from linux/include/xen/page.h:28,
> >>                  from linux/arch/arm64/xen/../../arm/xen/grant-table.c:33:
> >> linux/arch/arm64/include/asm/pgtable.h: In function 'set_pte_at':
> >> linux/include/linux/mmdebug.h:49:39: error: implicit declaration of function 'BUILD_BUG_ON_INVALID' [-Werror=implicit-function-declaration]
> >>  #define VM_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
> >>                                        ^
> >> linux/arch/arm64/include/asm/pgtable.h:281:3: note: in expansion of macro 'VM_WARN_ONCE'
> >>    VM_WARN_ONCE(!pte_young(pte),
> >>    ^
> >>
> >> This has been introduced by commit 82d340081b6f71237373d1452e3573a5a122794c
> >> "arm64: Improve error reporting on set_pte_at() checks". This is because
> >> mmdebug.h relies on the includer to properly include the dependencies.
> >>
> >> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> >>
> >> ---
> >> Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> >> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> >> Cc: Will Deacon <will.deacon@xxxxxxx>
> >>
> >>     I was tempted to add the missing include in linux/mmdebug.h but I'm
> >>     not sure about the policy for headers inclusion in Linux.
> > 
> > Normally, I would say that mmdebug.h should include whichever headers it
> > needs but for a quicker fix, I'm fine with including linux/bug.h (and
> > probably removing the asm/bug.h include in asm/pgtable.h).
> 
> The linux/bug.h will only be included when __ASSEMBLY__ is not defined
> which asm/bug.h is included even for assembly file.
> 
> Note that it's not possible to include linux/bug.h for assembly file
> because the headers is not correctly protected.
> 
> As I don't know if asm/bug.h is useful in pgtable.h, I've decided to
> keep it.

I don't know why it's there either. Anyway, I'll apply your patch and
try to remove asm/bug.h as well. If the build fails, I'll add it back.

-- 
Catalin
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