bpf: Add kernel/bpftool asm support for new instructions

Add asm support for new instructions so kernel verifier and bpftool
xlated insn dumps can have proper asm syntax for new instructions.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c
index 7b4afb7..d7bff60 100644 (file)
--- a/kernel/bpf/disasm.c
+++ b/kernel/bpf/disasm.c
@@ -87,6 +87,17 @@ const char *const bpf_alu_string[16] = {
        [BPF_END >> 4]  = "endian",
 };
 
+const char *const bpf_alu_sign_string[16] = {
+       [BPF_DIV >> 4]  = "s/=",
+       [BPF_MOD >> 4]  = "s%=",
+};
+
+const char *const bpf_movsx_string[4] = {
+       [0] = "(s8)",
+       [1] = "(s16)",
+       [3] = "(s32)",
+};
+
 static const char *const bpf_atomic_alu_string[16] = {
        [BPF_ADD >> 4]  = "add",
        [BPF_AND >> 4]  = "and",
@@ -101,6 +112,12 @@ static const char *const bpf_ldst_string[] = {
        [BPF_DW >> 3] = "u64",
 };
 
+static const char *const bpf_ldsx_string[] = {
+       [BPF_W >> 3]  = "s32",
+       [BPF_H >> 3]  = "s16",
+       [BPF_B >> 3]  = "s8",
+};
+
 static const char *const bpf_jmp_string[16] = {
        [BPF_JA >> 4]   = "jmp",
        [BPF_JEQ >> 4]  = "==",
@@ -128,6 +145,26 @@ static void print_bpf_end_insn(bpf_insn_print_t verbose,
                insn->imm, insn->dst_reg);
 }
 
+static void print_bpf_bswap_insn(bpf_insn_print_t verbose,
+                              void *private_data,
+                              const struct bpf_insn *insn)
+{
+       verbose(private_data, "(%02x) r%d = bswap%d r%d\n",
+               insn->code, insn->dst_reg,
+               insn->imm, insn->dst_reg);
+}
+
+static bool is_sdiv_smod(const struct bpf_insn *insn)
+{
+       return (BPF_OP(insn->code)  == BPF_DIV || BPF_OP(insn->code) == BPF_MOD) &&
+              insn->off == 1;
+}
+
+static bool is_movsx(const struct bpf_insn *insn)
+{
+       return BPF_OP(insn->code) == BPF_MOV && insn->off != 0;
+}
+
 void print_bpf_insn(const struct bpf_insn_cbs *cbs,
                    const struct bpf_insn *insn,
                    bool allow_ptr_leaks)
@@ -138,7 +175,7 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
        if (class == BPF_ALU || class == BPF_ALU64) {
                if (BPF_OP(insn->code) == BPF_END) {
                        if (class == BPF_ALU64)
-                               verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
+                               print_bpf_bswap_insn(verbose, cbs->private_data, insn);
                        else
                                print_bpf_end_insn(verbose, cbs->private_data, insn);
                } else if (BPF_OP(insn->code) == BPF_NEG) {
@@ -147,17 +184,20 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
                                insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
                                insn->dst_reg);
                } else if (BPF_SRC(insn->code) == BPF_X) {
-                       verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
+                       verbose(cbs->private_data, "(%02x) %c%d %s %s%c%d\n",
                                insn->code, class == BPF_ALU ? 'w' : 'r',
                                insn->dst_reg,
-                               bpf_alu_string[BPF_OP(insn->code) >> 4],
+                               is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4]
+                                                  : bpf_alu_string[BPF_OP(insn->code) >> 4],
+                               is_movsx(insn) ? bpf_movsx_string[(insn->off >> 3) - 1] : "",
                                class == BPF_ALU ? 'w' : 'r',
                                insn->src_reg);
                } else {
                        verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
                                insn->code, class == BPF_ALU ? 'w' : 'r',
                                insn->dst_reg,
-                               bpf_alu_string[BPF_OP(insn->code) >> 4],
+                               is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4]
+                                                  : bpf_alu_string[BPF_OP(insn->code) >> 4],
                                insn->imm);
                }
        } else if (class == BPF_STX) {
@@ -218,13 +258,15 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
                        verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
                }
        } else if (class == BPF_LDX) {
-               if (BPF_MODE(insn->code) != BPF_MEM) {
+               if (BPF_MODE(insn->code) != BPF_MEM && BPF_MODE(insn->code) != BPF_MEMSX) {
                        verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
                        return;
                }
                verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
                        insn->code, insn->dst_reg,
-                       bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
+                       BPF_MODE(insn->code) == BPF_MEM ?
+                                bpf_ldst_string[BPF_SIZE(insn->code) >> 3] :
+                                bpf_ldsx_string[BPF_SIZE(insn->code) >> 3],
                        insn->src_reg, insn->off);
        } else if (class == BPF_LD) {
                if (BPF_MODE(insn->code) == BPF_ABS) {
@@ -279,6 +321,9 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
                } else if (insn->code == (BPF_JMP | BPF_JA)) {
                        verbose(cbs->private_data, "(%02x) goto pc%+d\n",
                                insn->code, insn->off);
+               } else if (insn->code == (BPF_JMP32 | BPF_JA)) {
+                       verbose(cbs->private_data, "(%02x) gotol pc%+d\n",
+                               insn->code, insn->imm);
                } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
                        verbose(cbs->private_data, "(%02x) exit\n", insn->code);
                } else if (BPF_SRC(insn->code) == BPF_X) {