2022-09-02 16:11:59

by Xu Kuohai

[permalink] [raw]
Subject: [PATCH bpf-next 0/2] Jit BPF_CALL to direct call when possible

Currently BPF_CALL is always jited to indirect call, but when target is
in the range of direct call, a BPF_CALL can be jited to direct call.

For example, the following BPF_CALL

call __htab_map_lookup_elem

is always jited to an indirect call:

mov x10, #0xffffffffffff18f4
movk x10, #0x821, lsl #16
movk x10, #0x8000, lsl #32
blr x10

When the target is in the range of a direct call, it can be jited to:

bl 0xfffffffffd33bc98

This patchset does such jit.

Xu Kuohai (2):
bpf, arm64: Jit BPF_CALL to direct call when possible
bpf, arm64: Eliminate false -EFBIG error in bpf trampoline

arch/arm64/net/bpf_jit_comp.c | 136 ++++++++++++++++++++++------------
1 file changed, 87 insertions(+), 49 deletions(-)

--
2.30.2