From: Maxim Mikityanskiy <maxtram95@gmail.com>
To: Eduard Zingerman <eddyz87@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Mykola Lysenko <mykolal@fb.com>,
Shuah Khan <shuah@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
bpf@vger.kernel.org, linux-kselftest@vger.kernel.org,
netdev@vger.kernel.org, Maxim Mikityanskiy <maxim@isovalent.com>
Subject: [PATCH bpf-next 06/15] bpf: Add the assign_scalar_id_before_mov function
Date: Wed, 20 Dec 2023 23:40:04 +0200 [thread overview]
Message-ID: <20231220214013.3327288-7-maxtram95@gmail.com> (raw)
In-Reply-To: <20231220214013.3327288-1-maxtram95@gmail.com>
From: Maxim Mikityanskiy <maxim@isovalent.com>
Extract the common code that generates a register ID for src_reg before
MOV if needed into a new function. This function will also be used in
a following commit.
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
---
kernel/bpf/verifier.c | 33 +++++++++++++++++++--------------
1 file changed, 19 insertions(+), 14 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 89f8c527ed3c..a703e3adedd3 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4401,6 +4401,18 @@ static bool __is_pointer_value(bool allow_ptr_leaks,
return reg->type != SCALAR_VALUE;
}
+static void assign_scalar_id_before_mov(struct bpf_verifier_env *env,
+ struct bpf_reg_state *src_reg)
+{
+ if (src_reg->type == SCALAR_VALUE && !src_reg->id &&
+ !tnum_is_const(src_reg->var_off))
+ /* Ensure that src_reg has a valid ID that will be copied to
+ * dst_reg and then will be used by find_equal_scalars() to
+ * propagate min/max range.
+ */
+ src_reg->id = ++env->id_gen;
+}
+
/* Copy src state preserving dst->parent and dst->live fields */
static void copy_register_state(struct bpf_reg_state *dst, const struct bpf_reg_state *src)
{
@@ -13886,20 +13898,13 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
if (BPF_SRC(insn->code) == BPF_X) {
struct bpf_reg_state *src_reg = regs + insn->src_reg;
struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
- bool need_id = src_reg->type == SCALAR_VALUE && !src_reg->id &&
- !tnum_is_const(src_reg->var_off);
if (BPF_CLASS(insn->code) == BPF_ALU64) {
if (insn->off == 0) {
/* case: R1 = R2
* copy register state to dest reg
*/
- if (need_id)
- /* Assign src and dst registers the same ID
- * that will be used by find_equal_scalars()
- * to propagate min/max range.
- */
- src_reg->id = ++env->id_gen;
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
dst_reg->live |= REG_LIVE_WRITTEN;
dst_reg->subreg_def = DEF_NOT_SUBREG;
@@ -13914,8 +13919,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
bool no_sext;
no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
- if (no_sext && need_id)
- src_reg->id = ++env->id_gen;
+ if (no_sext)
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
if (!no_sext)
dst_reg->id = 0;
@@ -13937,8 +13942,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
if (insn->off == 0) {
bool is_src_reg_u32 = src_reg->umax_value <= U32_MAX;
- if (is_src_reg_u32 && need_id)
- src_reg->id = ++env->id_gen;
+ if (is_src_reg_u32)
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
/* Make sure ID is cleared if src_reg is not in u32
* range otherwise dst_reg min/max could be incorrectly
@@ -13952,8 +13957,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
/* case: W1 = (s8, s16)W2 */
bool no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
- if (no_sext && need_id)
- src_reg->id = ++env->id_gen;
+ if (no_sext)
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
if (!no_sext)
dst_reg->id = 0;
--
2.42.1
next prev parent reply other threads:[~2023-12-20 21:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-20 21:39 [PATCH bpf-next 00/15] Improvements for tracking scalars in the BPF verifier Maxim Mikityanskiy
2023-12-20 21:39 ` [PATCH bpf-next 01/15] selftests/bpf: Fix the u64_offset_to_skb_data test Maxim Mikityanskiy
2023-12-26 9:52 ` Shung-Hsi Yu
2023-12-26 10:38 ` Maxim Mikityanskiy
2023-12-26 13:22 ` Shung-Hsi Yu
2024-01-04 2:22 ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 02/15] bpf: make infinite loop detection in is_state_visited() exact Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 03/15] selftests/bpf: check if imprecise stack spills confuse infinite loop detection Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 04/15] bpf: Make bpf_for_each_spilled_reg consider narrow spills Maxim Mikityanskiy
2024-01-04 2:25 ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 05/15] selftests/bpf: Add a test case for 32-bit spill tracking Maxim Mikityanskiy
2024-01-04 2:25 ` Eduard Zingerman
2023-12-20 21:40 ` Maxim Mikityanskiy [this message]
2024-01-04 2:26 ` [PATCH bpf-next 06/15] bpf: Add the assign_scalar_id_before_mov function Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 07/15] bpf: Add the get_reg_width function Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 08/15] bpf: Assign ID to scalars on spill Maxim Mikityanskiy
2023-12-25 3:15 ` Alexei Starovoitov
2023-12-25 21:11 ` Maxim Mikityanskiy
2023-12-25 21:26 ` Alexei Starovoitov
2024-01-04 2:26 ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 09/15] selftests/bpf: Test assigning " Maxim Mikityanskiy
2024-01-04 2:26 ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 10/15] bpf: Track spilled unbounded scalars Maxim Mikityanskiy
2024-01-04 2:26 ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 11/15] selftests/bpf: Test tracking " Maxim Mikityanskiy
2024-01-04 2:26 ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 12/15] bpf: Preserve boundaries and track scalars on narrowing fill Maxim Mikityanskiy
2023-12-26 5:29 ` Shung-Hsi Yu
2024-01-04 2:27 ` Eduard Zingerman
2024-01-05 17:48 ` Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 13/15] selftests/bpf: Add test cases for " Maxim Mikityanskiy
2024-01-04 2:26 ` Eduard Zingerman
2023-12-20 21:40 ` [PATCH bpf-next 14/15] bpf: Optimize state pruning for spilled scalars Maxim Mikityanskiy
2023-12-20 21:40 ` [PATCH bpf-next 15/15] selftests/bpf: states pruning checks for scalar vs STACK_{MISC,ZERO} Maxim Mikityanskiy
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