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Subject[PATCH AUTOSEL for 4.14 47/51] tools include: Do not use poison with C++
Date
From: Arnaldo Carvalho de Melo <acme@redhat.com>

[ Upstream commit 6ae8eefc6c8fe050f057781b70a83262eb0a61ee ]

LIST_POISON[12] are used to initialize list_head and hlist_node
pointers, and do void pointer arithmetic, which C++ doesn't like, so, to
avoid drifting from the kernel by introducing some HLIST_POISON to do
away with void pointer math, just make those poisoned pointers be NULL
when building it with a C++ compiler.

Noticed with:

$ make LLVM_CONFIG=/usr/bin/llvm-config-3.9 LIBCLANGLLVM=1
CXX util/c++/clang.o
CXX util/c++/clang-test.o
In file included from /home/lizj/linux/tools/include/linux/list.h:5:0,
from /home/lizj/linux/tools/perf/util/namespaces.h:13,
from /home/lizj/linux/tools/perf/util/util.h:15,
from /home/lizj/linux/tools/perf/util/util-cxx.h:20,
from util/c++/clang-c.h:5,
from util/c++/clang-test.cpp:2:
/home/lizj/linux/tools/include/linux/list.h: In function ‘void list_del(list_head*)’:
/home/lizj/linux/tools/include/linux/poison.h:14:31: error: pointer of type ‘void *’ used in arithmetic [-Werror=pointer-arith]
# define POISON_POINTER_DELTA 0
^
/home/lizj/linux/tools/include/linux/poison.h:22:41: note: in expansion of macro ‘POISON_POINTER_DELTA’
#define LIST_POISON1 ((void *) 0x100 + POISON_POINTER_DELTA)
^
/home/lizj/linux/tools/include/linux/list.h:107:16: note: in expansion of macro ‘LIST_POISON1’
entry->next = LIST_POISON1;
^
In file included from /home/lizj/linux/tools/perf/util/namespaces.h:13:0,
from /home/lizj/linux/tools/perf/util/util.h:15,
from /home/lizj/linux/tools/perf/util/util-cxx.h:20,
from util/c++/clang-c.h:5,
from util/c++/clang-test.cpp:2:
/home/lizj/linux/tools/include/linux/list.h:107:14: error: invalid conversion from ‘void*’ to ‘list_head*’ [-fpermissive]

Reported-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Philip Li <philip.li@intel.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-m5ei2o0mjshucbr28baf5lqz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
---
tools/include/linux/poison.h | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/tools/include/linux/poison.h b/tools/include/linux/poison.h
index 4bf6777a8a03..9fdcd3eaac3b 100644
--- a/tools/include/linux/poison.h
+++ b/tools/include/linux/poison.h
@@ -15,6 +15,10 @@
# define POISON_POINTER_DELTA 0
#endif

+#ifdef __cplusplus
+#define LIST_POISON1 NULL
+#define LIST_POISON2 NULL
+#else
/*
* These are non-NULL pointers that will result in page faults
* under normal circumstances, used to verify that nobody uses
@@ -22,6 +26,7 @@
*/
#define LIST_POISON1 ((void *) 0x100 + POISON_POINTER_DELTA)
#define LIST_POISON2 ((void *) 0x200 + POISON_POINTER_DELTA)
+#endif

/********** include/linux/timer.h **********/
/*
--
2.11.0
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