Merge pull request #181 from Alan-Jowett/jmp32

Add support for BMP_JMP32 class
Alan-Jowett · Jan 16, 2024 · 787d8f2 · 787d8f2
2 parents d25c3f2 + e91a2b7
commit 787d8f2
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Showing 4 changed files with 23 additions and 4 deletions.
diff --git a/src/bpf_assembler.cc b/src/bpf_assembler.cc
@@ -287,9 +287,12 @@ typedef class _bpf_assembler
     _encode_jmp(const std::string& mnemonic, const std::vector<std::string>& operands)
     {
         ebpf_inst inst{};
-        inst.opcode |= EBPF_CLS_JMP;
         if (mnemonic == "ja") {
+            inst.opcode = EBPF_CLS_JMP;
             inst.offset = _decode_jump_target(operands[0]);
+        } else if (mnemonic == "ja32") {
+            inst.opcode = EBPF_CLS_JMP32;
+            inst.imm = _decode_jump_target(operands[0]);
         } else if (mnemonic == "exit") {
             inst.opcode = EBPF_OP_EXIT;
         } else if (mnemonic == "call") {
@@ -310,7 +313,7 @@ typedef class _bpf_assembler
                 throw std::runtime_error("Invalid call mode");
             }
         } else {
-            mnemonic.ends_with("32") ? inst.opcode = EBPF_CLS_JMP32 : inst.opcode |= EBPF_CLS_JMP;
+            mnemonic.ends_with("32") ? inst.opcode = EBPF_CLS_JMP32 : inst.opcode = EBPF_CLS_JMP;
             auto iter =
                 _bpf_encode_jmp_ops.find(mnemonic.ends_with("32") ? mnemonic.substr(0, mnemonic.size() - 2) : mnemonic);
             // It is not possible to reach here with no match.
@@ -456,6 +459,7 @@ typedef class _bpf_assembler
         {"be64", {&_bpf_assembler::_encode_alu, 1}},  {"call", {&_bpf_assembler::_encode_jmp, 2}},
         {"div", {&_bpf_assembler::_encode_alu, 2}},   {"div32", {&_bpf_assembler::_encode_alu, 2}},
         {"exit", {&_bpf_assembler::_encode_jmp, 0}},  {"ja", {&_bpf_assembler::_encode_jmp, 1}},
+        {"ja32", {&_bpf_assembler::_encode_jmp, 1}},
         {"jeq", {&_bpf_assembler::_encode_jmp, 3}},   {"jeq32", {&_bpf_assembler::_encode_jmp, 3}},
         {"jge", {&_bpf_assembler::_encode_jmp, 3}},   {"jge32", {&_bpf_assembler::_encode_jmp, 3}},
         {"jgt", {&_bpf_assembler::_encode_jmp, 3}},   {"jgt32", {&_bpf_assembler::_encode_jmp, 3}},
@@ -636,7 +640,7 @@ typedef class _bpf_assembler
             if (iter == _labels.end()) {
                 throw std::runtime_error(std::string("Invalid label: ") + _jump_instructions[i].value());
             }
-            if (output[i].opcode == EBPF_OP_CALL) {
+            if (output[i].opcode == EBPF_OP_CALL || output[i].opcode == EBPF_OP_JA32) {
                 output[i].imm = static_cast<uint32_t>(iter->second - i - 1);
             } else {
                 output[i].offset = static_cast<uint16_t>(iter->second - i - 1);

diff --git a/src/ebpf.h b/src/ebpf.h
@@ -167,6 +167,7 @@ typedef struct ebpf_inst
 #define EBPF_MODE_JSLE 0xd0
 
 #define EBPF_OP_JA (EBPF_CLS_JMP | EBPF_MODE_JA)
+#define EBPF_OP_JA32 (EBPF_CLS_JMP32 | EBPF_MODE_JA)
 #define EBPF_OP_JEQ_IMM (EBPF_CLS_JMP | EBPF_SRC_IMM | EBPF_MODE_JEQ)
 #define EBPF_OP_JEQ_REG (EBPF_CLS_JMP | EBPF_SRC_REG | EBPF_MODE_JEQ)
 #define EBPF_OP_JGT_IMM (EBPF_CLS_JMP | EBPF_SRC_IMM | EBPF_MODE_JGT)

diff --git a/src/opcode_names.h b/src/opcode_names.h
@@ -101,6 +101,7 @@ static const std::map<uint8_t, std::string> opcode_names = {
     {(EBPF_CLS_ALU64 | EBPF_SRC_REG | 0x30), "EBPF_OP_DIV64_REG"},
     {(EBPF_CLS_JMP | 0x90), "EBPF_OP_EXIT"},
     {(EBPF_CLS_JMP | 0x00), "EBPF_OP_JA"},
+    {(EBPF_CLS_JMP32 | 0x00), "EBPF_OP_JA32"},
     {(EBPF_CLS_JMP | EBPF_SRC_IMM | 0x10), "EBPF_OP_JEQ_IMM"},
     {(EBPF_CLS_JMP | EBPF_SRC_REG | 0x10), "EBPF_OP_JEQ_REG"},
     {(EBPF_CLS_JMP32 | EBPF_SRC_IMM | 0x10), "EBPF_OP_JEQ32_IMM"},
@@ -202,7 +203,7 @@ static const std::set<bpf_conformance_instruction_t, InstCmp> instructions_from_
     {bpf_conformance_test_cpu_version_t::v1, 0x00},
     {bpf_conformance_test_cpu_version_t::v1, 0x04},
     {bpf_conformance_test_cpu_version_t::v1, 0x05},
-    {bpf_conformance_test_cpu_version_t::v3, 0x06},
+    {bpf_conformance_test_cpu_version_t::v4, 0x06},
     {bpf_conformance_test_cpu_version_t::v1, 0x07},
     {bpf_conformance_test_cpu_version_t::v1, 0x0c},
     {bpf_conformance_test_cpu_version_t::v1, 0x0f},

diff --git a/tests/ja32.data b/tests/ja32.data
@@ -0,0 +1,13 @@
+# Copyright (c) Big Switch Networks, Inc
+# SPDX-License-Identifier: Apache-2.0
+-- asm
+mov %r1, 0
+ja32 L2
+L1:
+mov %r2, 0
+exit
+L2:
+mov %r0, 0
+ja32 L1
+-- result
+0x0