From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Jordan Niethe <jniethe5@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Johan Almbladh <johan.almbladh@anyfinetworks.com>,
Song Liu <songliubraving@fb.com>
Cc: <bpf@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Subject: [PATCH v2 04/10] powerpc/bpf: Fix BPF_SUB when imm == 0x80000000
Date: Wed, 6 Oct 2021 01:55:23 +0530 [thread overview]
Message-ID: <fc4b1276eb10761fd7ce0814c8dd089da2815251.1633464148.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1633464148.git.naveen.n.rao@linux.vnet.ibm.com>
We aren't handling subtraction involving an immediate value of
0x80000000 properly. Fix the same.
Fixes: 156d0e290e969c ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
Changelog:
- Split up BPF_ADD and BPF_SUB cases per Christophe's comments
arch/powerpc/net/bpf_jit_comp64.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index d67f6d62e2e1ff..6626e6c17d4ed2 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -330,18 +330,25 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
EMIT(PPC_RAW_SUB(dst_reg, dst_reg, src_reg));
goto bpf_alu32_trunc;
case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */
- case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */
case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */
+ if (!imm) {
+ goto bpf_alu32_trunc;
+ } else if (imm >= -32768 && imm < 32768) {
+ EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(imm)));
+ } else {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ EMIT(PPC_RAW_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]));
+ }
+ goto bpf_alu32_trunc;
+ case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */
case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */
- if (BPF_OP(code) == BPF_SUB)
- imm = -imm;
- if (imm) {
- if (imm >= -32768 && imm < 32768)
- EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(imm)));
- else {
- PPC_LI32(b2p[TMP_REG_1], imm);
- EMIT(PPC_RAW_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]));
- }
+ if (!imm) {
+ goto bpf_alu32_trunc;
+ } else if (imm > -32768 && imm < 32768) {
+ EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(-imm)));
+ } else {
+ PPC_LI32(b2p[TMP_REG_1], imm);
+ EMIT(PPC_RAW_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]));
}
goto bpf_alu32_trunc;
case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */
--
2.33.0
next prev parent reply other threads:[~2021-10-05 20:26 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 20:25 [PATCH v2 00/10] powerpc/bpf: Various fixes Naveen N. Rao
2021-10-05 20:25 ` [PATCH v2 01/10] powerpc/lib: Add helper to check if offset is within conditional branch range Naveen N. Rao
2021-10-06 4:50 ` Christophe Leroy
2021-10-05 20:25 ` [PATCH v2 02/10] powerpc/bpf: Validate branch ranges Naveen N. Rao
2021-10-06 4:51 ` LEROY Christophe
2021-10-06 4:51 ` Christophe Leroy
2021-10-05 20:25 ` [PATCH v2 03/10] powerpc/bpf: Fix BPF_MOD when imm == 1 Naveen N. Rao
2021-10-06 4:52 ` Christophe Leroy
2021-10-05 20:25 ` Naveen N. Rao [this message]
2021-10-06 4:55 ` [PATCH v2 04/10] powerpc/bpf: Fix BPF_SUB when imm == 0x80000000 Christophe Leroy
2021-10-07 8:47 ` Naveen N. Rao
2021-10-05 20:25 ` [PATCH v2 05/10] powerpc/security: Add a helper to query stf_barrier type Naveen N. Rao
2021-10-05 20:25 ` [PATCH v2 06/10] powerpc/bpf: Emit stf barrier instruction sequences for BPF_NOSPEC Naveen N. Rao
2021-10-05 20:25 ` [PATCH v2 07/10] powerpc/bpf ppc32: Fix ALU32 BPF_ARSH operation Naveen N. Rao
2021-10-06 4:56 ` Christophe Leroy
2021-10-05 20:25 ` [PATCH v2 08/10] powerpc/bpf ppc32: Fix JMP32_JSET_K Naveen N. Rao
2021-10-06 5:00 ` Christophe Leroy
2021-10-05 20:25 ` [PATCH v2 09/10] powerpc/bpf ppc32: Do not emit zero extend instruction for 64-bit BPF_END Naveen N. Rao
2021-10-06 5:03 ` Christophe Leroy
2021-10-05 20:25 ` [PATCH v2 10/10] powerpc/bpf ppc32: Fix BPF_SUB when imm == 0x80000000 Naveen N. Rao
2021-10-06 5:02 ` Christophe Leroy
2021-10-08 13:22 ` [PATCH v2 00/10] powerpc/bpf: Various fixes Michael Ellerman
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