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bpf: free up BPF_JMP | BPF_CALL | BPF_X opcode 

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 <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexei Starovoitov 2017-05-30 13:31:27 -07:00 committed by David S. Miller
parent d2e0ef493a
commit 71189fa9b0
8 changed files with 10 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/net/bpf_jit_comp.c
View File

@ -586,7 +586,7 @@ emit_cond_jmp:
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;

2
arch/powerpc/net/bpf_jit_comp64.c
View File

@ -938,7 +938,7 @@ common_load:
/*
* 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;

2
arch/s390/net/bpf_jit_comp.c
View File

@ -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

2
arch/sparc/net/bpf_jit_comp_64.c
View File

@ -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;

2
arch/x86/net/bpf_jit_comp.c
View File

@ -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;

3
include/linux/filter.h
View File

@ -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.

2
kernel/bpf/core.c
View File

@ -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,

2
kernel/bpf/verifier.c
View File

@ -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;
}