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bpf: Fix bpf_prog_pack build for ppc64_defconfig

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bpf_prog_pack causes build error with powerpc ppc64_defconfig:

kernel/bpf/core.c:830:23: error: variably modified 'bitmap' at file scope
  830 |         unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
      |                       ^~~~~~

This is because the marco expands as:

unsigned long bitmap[((((((1UL) << (16 + __pte_index_size)) / (1 << 6))) \
     + ((sizeof(long) * 8)) - 1) / ((sizeof(long) * 8)))];

where __pte_index_size is a global variable.

Fix it by turning bitmap into a 0-length array.

Fixes: 57631054fa ("bpf: Introduce bpf_prog_pack allocator")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220211024939.2962537-1-song@kernel.org
This commit is contained in:
Song Liu 2022-02-10 18:49:39 -08:00 committed by Alexei Starovoitov
parent a5a358abbc
commit 4cc0991abd
1 changed files with 2 additions and 2 deletions
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4
kernel/bpf/core.c
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@ -827,7 +827,7 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
struct bpf_prog_pack {
struct list_head list;
void *ptr;
unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
unsigned long bitmap[];
};
#define BPF_PROG_MAX_PACK_PROG_SIZE BPF_PROG_PACK_SIZE
@ -840,7 +840,7 @@ static struct bpf_prog_pack *alloc_new_pack(void)
{
struct bpf_prog_pack *pack;
pack = kzalloc(sizeof(*pack), GFP_KERNEL);
pack = kzalloc(sizeof(*pack) + BITS_TO_BYTES(BPF_PROG_CHUNK_COUNT), GFP_KERNEL);
if (!pack)
return NULL;
pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);