From 0845c3db7bf5c4ceb7100bcd8fd594d9ccf3c29a Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 27 Jul 2023 18:12:13 -0700 Subject: [PATCH] bpf: Support new unconditional bswap instruction The existing 'be' and 'le' insns will do conditional bswap depends on host endianness. This patch implements unconditional bswap insns. Acked-by: Eduard Zingerman Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20230728011213.3712808-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov --- arch/x86/net/bpf_jit_comp.c | 1 + kernel/bpf/core.c | 14 ++++++++++++++ kernel/bpf/verifier.c | 7 +++++-- 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 031ef3c..4942a4c 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1322,6 +1322,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image break; case BPF_ALU | BPF_END | BPF_FROM_BE: + case BPF_ALU64 | BPF_END | BPF_FROM_LE: switch (imm32) { case 16: /* Emit 'ror %ax, 8' to swap lower 2 bytes */ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c37c454..ad58697 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1524,6 +1524,7 @@ EXPORT_SYMBOL_GPL(__bpf_call_base); INSN_3(ALU64, DIV, X), \ INSN_3(ALU64, MOD, X), \ INSN_2(ALU64, NEG), \ + INSN_3(ALU64, END, TO_LE), \ /* Immediate based. */ \ INSN_3(ALU64, ADD, K), \ INSN_3(ALU64, SUB, K), \ @@ -1848,6 +1849,19 @@ select_insn: break; } CONT; + ALU64_END_TO_LE: + switch (IMM) { + case 16: + DST = (__force u16) __swab16(DST); + break; + case 32: + DST = (__force u32) __swab32(DST); + break; + case 64: + DST = (__force u64) __swab64(DST); + break; + } + CONT; /* CALL */ JMP_CALL: diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7a6945b..a3dcaee 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3012,8 +3012,10 @@ static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn, } } + if (class == BPF_ALU64 && op == BPF_END && (insn->imm == 16 || insn->imm == 32)) + return false; + if (class == BPF_ALU64 || class == BPF_JMP || - /* BPF_END always use BPF_ALU class. */ (class == BPF_ALU && op == BPF_END && insn->imm == 64)) return true; @@ -13076,7 +13078,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } else { if (insn->src_reg != BPF_REG_0 || insn->off != 0 || (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) || - BPF_CLASS(insn->code) == BPF_ALU64) { + (BPF_CLASS(insn->code) == BPF_ALU64 && + BPF_SRC(insn->code) != BPF_TO_LE)) { verbose(env, "BPF_END uses reserved fields\n"); return -EINVAL; } -- 2.7.4