0e0bfacff7
Alexei added may_goto insn in [1]. The asm syntax for may_goto looks
like
may_goto <label>
The instruction represents a conditional branch but the condition is
implicit. Later in bpf kernel verifier, the 'may_goto <label>' insn will
be rewritten with an explicit condition. The encoding of 'may_goto' insn
is enforced in [2] and is also implemented in this patch.
In [3], 'may_goto' insn is encoded with raw bytes. I made the following
change
```
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -328,10 +328,7 @@ l_true: \
#define cond_break \
({ __label__ l_break, l_continue; \
- asm volatile goto("1:.byte 0xe5; \
- .byte 0; \
- .long ((%l[l_break] - 1b - 8) / 8) & 0xffff; \
- .short 0" \
+ asm volatile goto("may_goto %l[l_break]" \
:::: l_break); \
goto l_continue; \
l_break: break;
```
and ran the selftest with the latest llvm with this patch. All tests are
passed.
[1]
https://lore.kernel.org/bpf/20240306031929.42666-1-alexei.starovoitov@gmail.com/
[2]
https://lore.kernel.org/bpf/20240306031929.42666-2-alexei.starovoitov@gmail.com/
[3]
https://lore.kernel.org/bpf/20240306031929.42666-4-alexei.starovoitov@gmail.com/
128 lines
3.1 KiB
TableGen
128 lines
3.1 KiB
TableGen
//===-- BPFInstrFormats.td - BPF Instruction Formats -------*- tablegen -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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class BPFOpClass<bits<3> val> {
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bits<3> Value = val;
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}
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def BPF_LD : BPFOpClass<0x0>;
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def BPF_LDX : BPFOpClass<0x1>;
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def BPF_ST : BPFOpClass<0x2>;
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def BPF_STX : BPFOpClass<0x3>;
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def BPF_ALU : BPFOpClass<0x4>;
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def BPF_JMP : BPFOpClass<0x5>;
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def BPF_JMP32 : BPFOpClass<0x6>;
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def BPF_ALU64 : BPFOpClass<0x7>;
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class BPFSrcType<bits<1> val> {
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bits<1> Value = val;
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}
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def BPF_K : BPFSrcType<0x0>;
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def BPF_X : BPFSrcType<0x1>;
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class BPFArithOp<bits<4> val> {
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bits<4> Value = val;
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}
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def BPF_ADD : BPFArithOp<0x0>;
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def BPF_SUB : BPFArithOp<0x1>;
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def BPF_MUL : BPFArithOp<0x2>;
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def BPF_DIV : BPFArithOp<0x3>;
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def BPF_OR : BPFArithOp<0x4>;
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def BPF_AND : BPFArithOp<0x5>;
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def BPF_LSH : BPFArithOp<0x6>;
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def BPF_RSH : BPFArithOp<0x7>;
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def BPF_NEG : BPFArithOp<0x8>;
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def BPF_MOD : BPFArithOp<0x9>;
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def BPF_XOR : BPFArithOp<0xa>;
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def BPF_MOV : BPFArithOp<0xb>;
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def BPF_ARSH : BPFArithOp<0xc>;
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def BPF_END : BPFArithOp<0xd>;
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def BPF_XCHG : BPFArithOp<0xe>;
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def BPF_CMPXCHG : BPFArithOp<0xf>;
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class BPFEndDir<bits<1> val> {
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bits<1> Value = val;
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}
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def BPF_TO_LE : BPFSrcType<0x0>;
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def BPF_TO_BE : BPFSrcType<0x1>;
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class BPFJumpOp<bits<4> val> {
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bits<4> Value = val;
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}
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def BPF_JA : BPFJumpOp<0x0>;
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def BPF_JEQ : BPFJumpOp<0x1>;
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def BPF_JGT : BPFJumpOp<0x2>;
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def BPF_JGE : BPFJumpOp<0x3>;
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def BPF_JSET : BPFJumpOp<0x4>;
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def BPF_JNE : BPFJumpOp<0x5>;
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def BPF_JSGT : BPFJumpOp<0x6>;
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def BPF_JSGE : BPFJumpOp<0x7>;
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def BPF_CALL : BPFJumpOp<0x8>;
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def BPF_EXIT : BPFJumpOp<0x9>;
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def BPF_JLT : BPFJumpOp<0xa>;
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def BPF_JLE : BPFJumpOp<0xb>;
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def BPF_JSLT : BPFJumpOp<0xc>;
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def BPF_JSLE : BPFJumpOp<0xd>;
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def BPF_JCOND : BPFJumpOp<0xe>;
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class BPFWidthModifer<bits<2> val> {
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bits<2> Value = val;
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}
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def BPF_W : BPFWidthModifer<0x0>;
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def BPF_H : BPFWidthModifer<0x1>;
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def BPF_B : BPFWidthModifer<0x2>;
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def BPF_DW : BPFWidthModifer<0x3>;
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class BPFModeModifer<bits<3> val> {
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bits<3> Value = val;
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}
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def BPF_IMM : BPFModeModifer<0x0>;
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def BPF_ABS : BPFModeModifer<0x1>;
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def BPF_IND : BPFModeModifer<0x2>;
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def BPF_MEM : BPFModeModifer<0x3>;
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def BPF_MEMSX : BPFModeModifer<0x4>;
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def BPF_ATOMIC : BPFModeModifer<0x6>;
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class BPFAtomicFlag<bits<4> val> {
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bits<4> Value = val;
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}
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def BPF_FETCH : BPFAtomicFlag<0x1>;
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class InstBPF<dag outs, dag ins, string asmstr, list<dag> pattern>
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: Instruction {
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field bits<64> Inst;
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field bits<64> SoftFail = 0;
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let Size = 8;
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let Namespace = "BPF";
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let DecoderNamespace = "BPF";
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BPFOpClass BPFClass;
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let Inst{58-56} = BPFClass.Value;
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dag OutOperandList = outs;
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dag InOperandList = ins;
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let AsmString = asmstr;
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let Pattern = pattern;
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}
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// Pseudo instructions
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class Pseudo<dag outs, dag ins, string asmstr, list<dag> pattern>
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: InstBPF<outs, ins, asmstr, pattern> {
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let Inst{63-0} = 0;
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let isPseudo = 1;
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}
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