feat(debug): multi-architecture debugger support for arm64, riscv64, loong64

Assisted-by: MiMo V2.5 Pro
This commit is contained in:
2026-08-21 00:35:21 +02:00
parent 3acbdd6533
commit de9e211ff1
32 changed files with 2276 additions and 659 deletions
+1 -121
View File
@@ -6,12 +6,9 @@
package debug
import (
"encoding/hex"
"fmt"
"os"
"runtime"
"strconv"
"strings"
"syscall"
"unsafe"
@@ -20,12 +17,8 @@ import (
"sourcedock.dev/petrbalvin/gasm-devkit/verify"
)
// RunTarget is the debuggee entry point (gasm debug --target). It
// assembles the file, maps the JIT code, registers itself for ptrace,
// stops, and then executes the named function. The parent debugger
// controls execution from there.
// RunTarget is the debuggee entry point (gasm debug --target).
func RunTarget(asmPath, funcName, argsFile, tmpDir string) error {
// Parse and assemble.
src, err := os.ReadFile(asmPath)
if err != nil {
return fmt.Errorf("debug target: %w", err)
@@ -39,7 +32,6 @@ func RunTarget(asmPath, funcName, argsFile, tmpDir string) error {
return fmt.Errorf("debug target: assemble: %w", err)
}
// Find the function.
var fl *asm.FuncLayout
for i := range img.Funcs {
if img.Funcs[i].Name == funcName {
@@ -51,24 +43,20 @@ func RunTarget(asmPath, funcName, argsFile, tmpDir string) error {
return fmt.Errorf("debug target: function %q not found", funcName)
}
// Map the entire image RWX (we need write access for breakpoints).
code := img.Bytes()
exec, err := mapRWX(code)
if err != nil {
return fmt.Errorf("debug target: mmap: %w", err)
}
// Write the code base address for the parent.
codeBase := uintptr(unsafe.Pointer(&exec[0]))
if err := os.WriteFile(tmpDir+"/codebase", []byte(fmt.Sprintf("%d", codeBase)), 0o644); err != nil {
return fmt.Errorf("debug target: write codebase: %w", err)
}
// Write function metadata (offset, size, args) for the parent.
meta := fmt.Sprintf("%d %d %d", fl.Offset, fl.Size, fl.Args)
os.WriteFile(tmpDir+"/funcmeta", []byte(meta), 0o644)
// Write label table for breakpoint resolution.
labelsFile, _ := os.Create(tmpDir + "/labels")
if labelsFile != nil {
for label, off := range fl.Labels {
@@ -77,7 +65,6 @@ func RunTarget(asmPath, funcName, argsFile, tmpDir string) error {
labelsFile.Close()
}
// Read the argument block.
args, err := os.ReadFile(argsFile)
if err != nil {
return fmt.Errorf("debug target: read args: %w", err)
@@ -88,7 +75,6 @@ func RunTarget(asmPath, funcName, argsFile, tmpDir string) error {
args = padded
}
// Read buffer specification if present.
bufSpecFile := tmpDir + "/bufspec"
if bufSpec, err := os.ReadFile(bufSpecFile); err == nil && len(bufSpec) > 0 {
args, err = setupBuffers(string(bufSpec), args, fl.Args, tmpDir)
@@ -97,131 +83,25 @@ func RunTarget(asmPath, funcName, argsFile, tmpDir string) error {
}
}
// Lock this goroutine to the current OS thread so the parent's
// ptrace (attached to this thread) controls the JIT execution.
runtime.LockOSThread()
// Request tracing by the parent, then stop. PTRACE_TRACEME makes
// the subsequent SIGSTOP a ptrace-stop (not a group-stop), giving
// the parent full control from the start.
if _, _, errno := syscall.Syscall(syscall.SYS_PTRACE, uintptr(syscall.PTRACE_TRACEME), 0, 0); errno != 0 {
return fmt.Errorf("debug target: PTRACE_TRACEME: %v", errno)
}
os.WriteFile(tmpDir+"/ready", []byte("ok"), 0o644)
syscall.Kill(syscall.Getpid(), syscall.SIGSTOP)
// --- Execution resumes here after the parent continues us ---
// Stop at the function entry point so the debugger can set breakpoints.
// The parent will continue us when ready.
os.WriteFile(tmpDir+"/entry", []byte("ok"), 0o644)
syscall.Kill(syscall.Getpid(), syscall.SIGSTOP)
// Prepare the ABI0 stack and call the function.
fnAddr := codeBase + uintptr(fl.Offset)
stackArgs := make([]byte, fl.Args)
copy(stackArgs, args)
_, callErr := verify.Call(fnAddr, stackArgs)
if callErr != nil {
// The function returned an error (shouldn't happen for valid code).
os.Exit(1)
}
os.Exit(0)
return nil
}
// mapRWX maps code into a read-write-execute region (needed for
// breakpoint patching via ptrace POKETEXT, though ptrace can write
// to any mapping regardless of permissions).
func mapRWX(code []byte) ([]byte, error) {
const pageSize = 4096
size := (len(code) + pageSize - 1) &^ (pageSize - 1)
mem, err := syscall.Mmap(-1, 0, size,
syscall.PROT_READ|syscall.PROT_WRITE|syscall.PROT_EXEC,
syscall.MAP_PRIVATE|syscall.MAP_ANON)
if err != nil {
return nil, err
}
copy(mem, code)
return mem, nil
}
// setupBuffers allocates buffers in the debuggee's memory and updates the
// argument block with pointers to them.
// Format: name:size:pattern[,name:size:pattern...]
// Patterns: zero, ones, seq, or hex (e.g. "deadbeef").
func setupBuffers(spec string, args []byte, argSize int, tmpDir string) ([]byte, error) {
// Parse the buffer spec.
type bufSpec struct {
name string
size int
pattern string
}
var specs []bufSpec
for _, part := range strings.Split(spec, ",") {
fields := strings.SplitN(part, ":", 3)
if len(fields) != 3 {
continue
}
size, err := strconv.Atoi(fields[1])
if err != nil || size <= 0 {
continue
}
specs = append(specs, bufSpec{name: fields[0], size: size, pattern: fields[2]})
}
if len(specs) == 0 {
return args, nil
}
// Allocate buffers and write their addresses to a file for the parent.
var bufAddrs []uint64
for _, s := range specs {
buf, err := syscall.Mmap(-1, 0, s.size,
syscall.PROT_READ|syscall.PROT_WRITE,
syscall.MAP_PRIVATE|syscall.MAP_ANON)
if err != nil {
return nil, fmt.Errorf("mmap buffer %s: %w", s.name, err)
}
fillBuffer(buf, s.pattern)
bufAddrs = append(bufAddrs, uint64(uintptr(unsafe.Pointer(&buf[0]))))
}
// Write buffer addresses to a file for the parent to read.
addrFile, err := os.Create(tmpDir + "/bufaddrs")
if err != nil {
return nil, err
}
for _, addr := range bufAddrs {
fmt.Fprintf(addrFile, "%d\n", addr)
}
addrFile.Close()
// For now, return the args unchanged. The parent will read bufaddrs
// and construct the final argument block with the correct pointers.
return args, nil
}
// fillBuffer fills a buffer with the specified pattern.
func fillBuffer(buf []byte, pattern string) {
switch pattern {
case "zero":
// Already zeroed by mmap.
case "ones":
for i := range buf {
buf[i] = 0xFF
}
case "seq":
for i := range buf {
buf[i] = byte(i)
}
default:
// Try to parse as hex.
if data, err := hex.DecodeString(pattern); err == nil && len(data) > 0 {
for i := range buf {
buf[i] = data[i%len(data)]
}
}
}
}