2015-01-23 5:41 GMT+09:00 Kim Phillips [off-list ref]:

On Thu, 22 Jan 2015 10:45:51 +0900
Joonsoo Kim [off-list ref] wrote:

quoted

On Wed, Jan 21, 2015 at 09:57:59PM +0900, Akinobu Mita wrote:

quoted

2015-01-21 9:07 GMT+09:00 Andrew Morton [off-list ref]:

quoted

On Tue, 20 Jan 2015 15:01:50 -0800 josh@joshtriplett.org wrote:

quoted

On Tue, Jan 20, 2015 at 02:02:00PM -0600, Kim Phillips wrote:

quoted

It's possible to configure DEBUG_PAGEALLOC without PAGE_POISONING on
ppc.  Fix building the generic kernel_map_pages() implementation in
this case:

  LD      init/built-in.o
mm/built-in.o: In function `free_pages_prepare':
mm/page_alloc.c:770: undefined reference to `.kernel_map_pages'
mm/built-in.o: In function `prep_new_page':
mm/page_alloc.c:933: undefined reference to `.kernel_map_pages'
mm/built-in.o: In function `map_pages':
mm/compaction.c:61: undefined reference to `.kernel_map_pages'
make: *** [vmlinux] Error 1

kernel_map_pages() is static inline function since commit 031bc5743f15
("mm/debug-pagealloc: make debug-pagealloc boottime configurable").

But there is old declaration in 'arch/powerpc/include/asm/cacheflush.h'.
Removing it or changing s/kernel_map_pages/__kernel_map_pages/ in this
header file or something can fix this problem?

The architecture which has ARCH_SUPPORTS_DEBUG_PAGEALLOC
including PPC should not build mm/debug-pagealloc.o

Yes, architecture with ARCH_SUPPORTS_DEBUG_PAGEALLOC should not build
mm/debug-pagealloc.o. I attach the patch to remove old declaration.
I hope it will fix Kim's problem.

-------------->8------------------
From 7cb9d1ed8a785df152cb8934e187031c8ebd1bb2 Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <redacted>
Date: Thu, 22 Jan 2015 10:28:58 +0900
Subject: [PATCH] mm/debug_pagealloc: fix build failure on ppc and some other
 archs

Kim Phillips reported following build failure.

  LD      init/built-in.o
  mm/built-in.o: In function `free_pages_prepare':
  mm/page_alloc.c:770: undefined reference to `.kernel_map_pages'
  mm/built-in.o: In function `prep_new_page':
  mm/page_alloc.c:933: undefined reference to `.kernel_map_pages'
  mm/built-in.o: In function `map_pages':
  mm/compaction.c:61: undefined reference to `.kernel_map_pages'
  make: *** [vmlinux] Error 1

Reason for this problem is that commit 031bc5743f15
("mm/debug-pagealloc: make debug-pagealloc boottime configurable") forgot
to remove old declaration of kernel_map_pages() in some architectures.
This patch removes them to fix build failure.

Reported-by: Kim Phillips <redacted>
Signed-off-by: Joonsoo Kim <redacted>
---

Thanks. Now I get this:

  LD      init/built-in.o
mm/built-in.o: In function `kernel_map_pages':
include/linux/mm.h:2076: undefined reference to `.__kernel_map_pages'
include/linux/mm.h:2076: undefined reference to `.__kernel_map_pages'
include/linux/mm.h:2076: undefined reference to `.__kernel_map_pages'
Makefile:925: recipe for target 'vmlinux' failed
make: *** [vmlinux] Error 1

but, AFAICT, that's not because this patch is invalid: it's because
__kernel_map_pages() isn't implemented in
arch/powerpc/mm/pgtable_64.c, i.e., for non-PPC_STD_MMU_64 PPC64
machines.

Then, in order to use generic __kernel_map_pages() in mm/debug-pagealloc.c,
CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC shouldn't be selected in
arch/powerpc/Kconfig, when CONFIG_PPC_STD_MMU_64 isn't defined.