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Add eBPF instruction CALLX for indirect calls #7972

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Add eBPF instruction CALLX for indirect calls #7972

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20 changes: 19 additions & 1 deletion Ghidra/Processors/eBPF/data/languages/eBPF.sinc
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,9 @@ define register offset=0 size=8 [ R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 P

# Instruction encoding: Insop:8, dst_reg:4, src_reg:4, off:16, imm:32 - from lsb to msb
define token instr(64)
llvm_imm_callx_zero=(36, 63)
imm=(32, 63) signed
llvm_reg_callx=(32, 35) # special encoding for callx instruction emitted by LLVM
off=(16, 31) signed
src=(12, 15)
dst=(8, 11)
Expand All @@ -31,7 +33,7 @@ define token immtoken(64)
;

#To operate with registers
attach variables [ src dst ] [ R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 _ _ _ _ _ ];
attach variables [ src dst llvm_reg_callx ] [ R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 _ _ _ _ _ ];

#Arithmetic instructions
#BPF_ALU64
Expand Down Expand Up @@ -356,4 +358,20 @@ disp32: reloc is imm [ reloc = inst_next + imm; ] { export *:4 reloc; }
call disp32;
}

# GCC encoding and LLVM 19.1+ encoding
:CALLX dst is op_alu_jmp_opcode=0x8 & op_alu_jmp_source=1 & op_insn_class=0x5 & src=0 & imm=0 & dst {
call [dst];
}

# LLVM encoding used until LLVM 19.1
# Introduced in https://github.com/llvm/llvm-project/commit/9a67245d881f4cf89fd8f897ae2cd0bccec49496
# Modified in https://github.com/llvm/llvm-project/commit/c43ad6c0fddac0bbed5e881801dd2bc2f9eeba2d
:CALLX llvm_reg_callx is op_alu_jmp_opcode=0x8 & op_alu_jmp_source=1 & op_insn_class=0x5 & dst=0 & src=0 & llvm_imm_callx_zero=0 & llvm_reg_callx {
call [llvm_reg_callx];
}
# Both CALLX encodings are matched when both dst and imm are zero
:CALLX R0 is op_alu_jmp_opcode=0x8 & op_alu_jmp_source=1 & op_insn_class=0x5 & dst=0 & src=0 & imm=0 & R0 {
call [R0];
}

:EXIT is op_alu_jmp_opcode=0x9 & op_alu_jmp_source=0 & op_insn_class=0x5 { return [*:8 R10]; }