libbpf: Add support for bpf_arena.

mmap() bpf_arena right after creation, since the kernel needs to
remember the address returned from mmap. This is user_vm_start.
LLVM will generate bpf_arena_cast_user() instructions where
necessary and JIT will add upper 32-bit of user_vm_start
to such pointers.

Fix up bpf_map_mmap_sz() to compute mmap size as
map->value_size * map->max_entries for arrays and
PAGE_SIZE * map->max_entries for arena.

Don't set BTF at arena creation time, since it doesn't support it.

Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

0 files changed, 0 insertions, 0 deletions