From dc7d7447b56bcc9cf79a9c22e4edad200a298e4c Mon Sep 17 00:00:00 2001 From: Xu Kuohai Date: Tue, 16 Apr 2024 14:42:07 +0800 Subject: bpf, arm64: Fix incorrect runtime stats When __bpf_prog_enter() returns zero, the arm64 register x20 that stores prog start time is not assigned to zero, causing incorrect runtime stats. To fix it, assign the return value of bpf_prog_enter() to x20 register immediately upon its return. Fixes: efc9909fdce0 ("bpf, arm64: Add bpf trampoline for arm64") Reported-by: Ivan Babrou Signed-off-by: Xu Kuohai Signed-off-by: Daniel Borkmann Tested-by: Ivan Babrou Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240416064208.2919073-2-xukuohai@huaweicloud.com --- arch/arm64/net/bpf_jit_comp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 122021f9bdfc..13eac43c632d 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1844,15 +1844,15 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l, emit_call(enter_prog, ctx); + /* save return value to callee saved register x20 */ + emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx); + /* if (__bpf_prog_enter(prog) == 0) * goto skip_exec_of_prog; */ branch = ctx->image + ctx->idx; emit(A64_NOP, ctx); - /* save return value to callee saved register x20 */ - emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx); - emit(A64_ADD_I(1, A64_R(0), A64_SP, args_off), ctx); if (!p->jited) emit_addr_mov_i64(A64_R(1), (const u64)p->insnsi, ctx); -- cgit v1.2.3