From 82ce364c6087e31ff9837380a4641a856284064c Mon Sep 17 00:00:00 2001 From: Shung-Hsi Yu Date: Wed, 8 Nov 2023 22:00:41 +0800 Subject: [PATCH] bpf: replace register_is_const() with is_reg_const() The addition of is_reg_const() in commit 171de12646d2 ("bpf: generalize is_branch_taken to handle all conditional jumps in one place") has made the register_is_const() redundant. Give the former has more feature, plus the fact the latter is only used in one place, replace register_is_const() with is_reg_const(), and remove the definition of register_is_const. This requires moving the definition of is_reg_const() further up. And since the comment of reg_const_value() reference is_reg_const(), move it up as well. Signed-off-by: Shung-Hsi Yu Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20231108140043.12282-1-shung-hsi.yu@suse.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9276e0abcb4be..993e4677bbe99 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4690,9 +4690,17 @@ static bool register_is_null(struct bpf_reg_state *reg) return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0); } -static bool register_is_const(struct bpf_reg_state *reg) +/* check if register is a constant scalar value */ +static bool is_reg_const(struct bpf_reg_state *reg, bool subreg32) +{ + return reg->type == SCALAR_VALUE && + tnum_is_const(subreg32 ? tnum_subreg(reg->var_off) : reg->var_off); +} + +/* assuming is_reg_const() is true, return constant value of a register */ +static u64 reg_const_value(struct bpf_reg_state *reg, bool subreg32) { - return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off); + return subreg32 ? tnum_subreg(reg->var_off).value : reg->var_off.value; } static bool __is_scalar_unbounded(struct bpf_reg_state *reg) @@ -10050,7 +10058,7 @@ record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, val = reg->var_off.value; max = map->max_entries; - if (!(register_is_const(reg) && val < max)) { + if (!(is_reg_const(reg, false) && val < max)) { bpf_map_key_store(aux, BPF_MAP_KEY_POISON); return 0; } @@ -14220,19 +14228,6 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, })); } -/* check if register is a constant scalar value */ -static bool is_reg_const(struct bpf_reg_state *reg, bool subreg32) -{ - return reg->type == SCALAR_VALUE && - tnum_is_const(subreg32 ? tnum_subreg(reg->var_off) : reg->var_off); -} - -/* assuming is_reg_const() is true, return constant value of a register */ -static u64 reg_const_value(struct bpf_reg_state *reg, bool subreg32) -{ - return subreg32 ? tnum_subreg(reg->var_off).value : reg->var_off.value; -} - /* * , currently assuming reg2 is a constant */