[PATCH 1/1] libbpf: Use (uintptr_t) for a u64 cast to a void pointer to fix build on 32-bit arches

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Noticed on several perf container builds:

  perfbuilder@number:~$ grep -B1 -A2 "cast to pointer"  dm.log/*\:*
  dm.log/ubuntu:18.04-x-arm-libbpf.c: In function 'bpf_object__create_maps':
  dm.log/ubuntu:18.04-x-arm:libbpf.c:5355:24: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
  dm.log/ubuntu:18.04-x-arm-     map->mmaped = mmap((void *)map->map_extra, bpf_map_mmap_sz(map),
  dm.log/ubuntu:18.04-x-arm-                        ^
  --
  dm.log/ubuntu:18.04-x-powerpc-libbpf.c: In function 'bpf_object__create_maps':
  dm.log/ubuntu:18.04-x-powerpc:libbpf.c:5355:24: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
  dm.log/ubuntu:18.04-x-powerpc-     map->mmaped = mmap((void *)map->map_extra, bpf_map_mmap_sz(map),
  dm.log/ubuntu:18.04-x-powerpc-                        ^
  --
  dm.log/ubuntu:18.04-x-sh4-libbpf.c: In function 'bpf_object__create_maps':
  dm.log/ubuntu:18.04-x-sh4:libbpf.c:5355:24: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
  dm.log/ubuntu:18.04-x-sh4-     map->mmaped = mmap((void *)map->map_extra, bpf_map_mmap_sz(map),
  dm.log/ubuntu:18.04-x-sh4-                        ^
  perfbuilder@number:~$

I think Namhyung mentioned as well on a chat conversation about noticing
this on a 32-bit build on Debian.

Fixes: 79ff13e99169ddb0 ("libbpf: Add support for bpf_arena.")
Reported-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/libbpf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index efab29b8935bd9f7..af0b0e24978558f8 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -14,6 +14,7 @@
 #define _GNU_SOURCE
 #endif
 #include <stdlib.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <libgen.h>
@@ -5352,7 +5353,7 @@ bpf_object__create_maps(struct bpf_object *obj)
 					goto err_out;
 			}
 			if (map->def.type == BPF_MAP_TYPE_ARENA) {
-				map->mmaped = mmap((void *)map->map_extra, bpf_map_mmap_sz(map),
+				map->mmaped = mmap((void *)(uintptr_t)map->map_extra, bpf_map_mmap_sz(map),
 						   PROT_READ | PROT_WRITE,
 						   map->map_extra ? MAP_SHARED | MAP_FIXED : MAP_SHARED,
 						   map->fd, 0);
-- 
2.44.0