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GP-1221: Using "missing cpsr" heuristic to disassemble Cortex-M as THUMB.

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Dan 2021-08-23 13:32:35 -04:00
parent c0739bbede
commit 11b82d7ccf
1 changed files with 32 additions and 23 deletions
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55
Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/platform/ArmDisassemblyInject.java
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@ -25,32 +25,34 @@ import ghidra.program.model.address.AddressSetView;
import ghidra.program.model.lang.Register;
import ghidra.program.model.lang.RegisterValue;
import ghidra.trace.model.memory.TraceMemoryRegisterSpace;
import ghidra.trace.model.memory.TraceMemoryState;
import ghidra.trace.model.program.TraceProgramView;
import ghidra.trace.model.thread.TraceThread;
import ghidra.util.Msg;
@DisassemblyInjectInfo(langIDs = {
"ARM:LE:32:v8",
"ARM:LE:32:v8T",
"ARM:LEBE:32:v8LEInstruction",
"ARM:BE:32:v8",
"ARM:BE:32:v8T",
"ARM:LE:32:v7",
"ARM:LEBE:32:v7LEInstruction",
"ARM:BE:32:v7",
"ARM:LE:32:Cortex",
"ARM:BE:32:Cortex",
"ARM:LE:32:v6",
"ARM:BE:32:v6",
"ARM:LE:32:v5t",
"ARM:BE:32:v5t",
"ARM:LE:32:v5",
"ARM:BE:32:v5",
"ARM:LE:32:v4t",
"ARM:BE:32:v4t",
"ARM:LE:32:v4",
"ARM:BE:32:v4",
})
@DisassemblyInjectInfo(
langIDs = {
"ARM:LE:32:v8",
"ARM:LE:32:v8T",
"ARM:LEBE:32:v8LEInstruction",
"ARM:BE:32:v8",
"ARM:BE:32:v8T",
"ARM:LE:32:v7",
"ARM:LEBE:32:v7LEInstruction",
"ARM:BE:32:v7",
"ARM:LE:32:Cortex",
"ARM:BE:32:Cortex",
"ARM:LE:32:v6",
"ARM:BE:32:v6",
"ARM:LE:32:v5t",
"ARM:BE:32:v5t",
"ARM:LE:32:v5",
"ARM:BE:32:v5",
"ARM:LE:32:v4t",
"ARM:BE:32:v4t",
"ARM:LE:32:v4",
"ARM:BE:32:v4",
})
public class ArmDisassemblyInject implements DisassemblyInject {
protected static final long THUMB_BIT = 0x20;
@ -78,9 +80,16 @@ public class ArmDisassemblyInject implements DisassemblyInject {
TraceMemoryRegisterSpace regs =
view.getTrace().getMemoryManager().getMemoryRegisterSpace(thread, false);
if (regs == null) {
/**
* Some variants (particularly Cortex-M) are missing cpsr This seems to indicate it only
* supports THUMB. There is an epsr (xpsr in gdb), but we don't have it in our models, and
* its TMode bit must be set, or it will fault.
*/
if (regs == null || regs.getState(view.getSnap(), cpsrReg) != TraceMemoryState.KNOWN) {
command.setInitialContext(new RegisterValue(tModeReg, BigInteger.ONE));
return;
}
RegisterValue cpsrVal = regs.getValue(view.getSnap(), cpsrReg);
if (isThumbMode(cpsrVal)) {
command.setInitialContext(new RegisterValue(tModeReg, BigInteger.ONE));