free up BPF_JMP | BPF_CALL | BPF_X opcode to be used by actual
indirect call by register and use kernel internal opcode to
mark call instruction into bpf_tail_call() helper.
Signed-off-by: Alexei Starovoitov <a...@kernel.org>
Acked-by: Daniel Borkmann <dan...@iogearbox.net>
---
arch/arm64/net/bpf_jit_comp.c | 2 +-
arch/powerpc/net/bpf_jit_comp64.c | 2 +-
arch/s390/net/bpf_jit_comp.c | 2 +-
arch/sparc/net/bpf_jit_comp_64.c | 2 +-
arch/x86/net/bpf_jit_comp.c | 2 +-
include/linux/filter.h | 3 +++
kernel/bpf/core.c | 2 +-
kernel/bpf/verifier.c | 2 +-
8 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 71f930501ade..b1d38eeb24f6 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -586,7 +586,7 @@ static int build_insn(const struct bpf_insn *insn, struct
jit_ctx *ctx)
break;
}
/* tail call */
- case BPF_JMP | BPF_CALL | BPF_X:
+ case BPF_JMP | BPF_TAIL_CALL:
if (emit_bpf_tail_call(ctx))
return -EFAULT;
break;
diff --git a/arch/powerpc/net/bpf_jit_comp64.c
b/arch/powerpc/net/bpf_jit_comp64.c
index aee2bb817ac6..a01366584a4b 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -938,7 +938,7 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32
*image,
/*
* Tail call
*/
- case BPF_JMP | BPF_CALL | BPF_X:
+ case BPF_JMP | BPF_TAIL_CALL:
ctx->seen |= SEEN_TAILCALL;
bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]);
break;
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 6e97a2e3fd8d..42ad3832586c 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -991,7 +991,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit,
struct bpf_prog *fp, int i
}
break;
}
- case BPF_JMP | BPF_CALL | BPF_X:
+ case BPF_JMP | BPF_TAIL_CALL:
/*
* Implicit input:
* B1: pointer to ctx
diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c
index 21de77419f48..4a52d34facf9 100644
--- a/arch/sparc/net/bpf_jit_comp_64.c
+++ b/arch/sparc/net/bpf_jit_comp_64.c
@@ -1217,7 +1217,7 @@ static int build_insn(const struct bpf_insn *insn, struct
jit_ctx *ctx)
}
/* tail call */
- case BPF_JMP | BPF_CALL |BPF_X:
+ case BPF_JMP | BPF_TAIL_CALL:
emit_tail_call(ctx);
break;
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index f58939393eef..fec12eaa0dec 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -877,7 +877,7 @@ xadd: if (is_imm8(insn->off))
}
break;
- case BPF_JMP | BPF_CALL | BPF_X:
+ case BPF_JMP | BPF_TAIL_CALL:
emit_bpf_tail_call(&prog);
break;
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 62d948f80730..a20ba40fcb73 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -57,6 +57,9 @@ struct bpf_prog_aux;
#define BPF_REG_AX MAX_BPF_REG
#define MAX_BPF_JIT_REG (MAX_BPF_REG + 1)
+/* unused opcode to mark special call to bpf_tail_call() helper */
+#define BPF_TAIL_CALL 0xf0
+
/* As per nm, we expose JITed images as text (code) section for
* kallsyms. That way, tools like perf can find it to match
* addresses.
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index dedf367f59bb..339289402b96 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -824,7 +824,7 @@ static unsigned int __bpf_prog_run(void *ctx, const struct
bpf_insn *insn)
[BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
/* Call instruction */
[BPF_JMP | BPF_CALL] = &&JMP_CALL,
- [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
+ [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
/* Jumps */
[BPF_JMP | BPF_JA] = &&JMP_JA,
[BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 339c8a1371de..28113d0e8e92 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3469,7 +3469,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
* that doesn't support bpf_tail_call yet
*/
insn->imm = 0;
- insn->code |= BPF_X;
+ insn->code = BPF_JMP | BPF_TAIL_CALL;
continue;
}
--
2.9.3
