[bpf] error when unknown bpf helper is called
Emit error when BPF backend sees a call to a global function or to an external symbol.
The kernel verifier only allows calls to predefined helpers from bpf.h
which are defined in 'enum bpf_func_id'. Such calls in assembler must
look like 'call [1-9]+' where number matches bpf_func_id.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 292204
diff --git a/llvm/lib/Target/BPF/BPFMCInstLower.cpp b/llvm/lib/Target/BPF/BPFMCInstLower.cpp
index f64defe..1faa1c0 100644
--- a/llvm/lib/Target/BPF/BPFMCInstLower.cpp
+++ b/llvm/lib/Target/BPF/BPFMCInstLower.cpp
@@ -29,6 +29,11 @@
return Printer.getSymbol(MO.getGlobal());
}
+MCSymbol *
+BPFMCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const {
+ return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
+}
+
MCOperand BPFMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
MCSymbol *Sym) const {
@@ -66,6 +71,9 @@
break;
case MachineOperand::MO_RegisterMask:
continue;
+ case MachineOperand::MO_ExternalSymbol:
+ MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
+ break;
case MachineOperand::MO_GlobalAddress:
MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
break;