58762685e3
Adds the low-level support for watchpoints (aka data breakpoints) to the native linux/amd64 backend. Does not add user interface or functioning support for watchpoints on stack variables. Updates #279
122 lines
3.5 KiB
Go
122 lines
3.5 KiB
Go
package native
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import (
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"syscall"
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"unsafe"
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sys "golang.org/x/sys/unix"
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"github.com/go-delve/delve/pkg/proc"
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"github.com/go-delve/delve/pkg/proc/amd64util"
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"github.com/go-delve/delve/pkg/proc/linutil"
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)
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func (t *nativeThread) restoreRegisters(savedRegs proc.Registers) error {
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sr := savedRegs.(*linutil.AMD64Registers)
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var restoreRegistersErr error
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t.dbp.execPtraceFunc(func() {
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oldRegs := (*sys.PtraceRegs)(sr.Regs)
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var currentRegs sys.PtraceRegs
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restoreRegistersErr = sys.PtraceGetRegs(t.ID, ¤tRegs)
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if restoreRegistersErr != nil {
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return
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}
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// restoreRegisters is only supposed to restore CPU registers, not FS_BASE and GS_BASE
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oldRegs.Fs_base = currentRegs.Fs_base
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oldRegs.Gs_base = currentRegs.Gs_base
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restoreRegistersErr = sys.PtraceSetRegs(t.ID, oldRegs)
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if restoreRegistersErr != nil {
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return
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}
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if sr.Fpregset.Xsave != nil {
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iov := sys.Iovec{Base: &sr.Fpregset.Xsave[0], Len: uint64(len(sr.Fpregset.Xsave))}
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_, _, restoreRegistersErr = syscall.Syscall6(syscall.SYS_PTRACE, sys.PTRACE_SETREGSET, uintptr(t.ID), _NT_X86_XSTATE, uintptr(unsafe.Pointer(&iov)), 0, 0)
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return
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}
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_, _, restoreRegistersErr = syscall.Syscall6(syscall.SYS_PTRACE, sys.PTRACE_SETFPREGS, uintptr(t.ID), uintptr(0), uintptr(unsafe.Pointer(&sr.Fpregset.AMD64PtraceFpRegs)), 0, 0)
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return
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})
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if restoreRegistersErr == syscall.Errno(0) {
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restoreRegistersErr = nil
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}
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return restoreRegistersErr
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}
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const debugRegUserOffset = 848 // offset of debug registers in the user struct, see source/arch/x86/kernel/ptrace.c
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func (t *nativeThread) withDebugRegisters(f func(*amd64util.DebugRegisters) error) error {
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var err error
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t.dbp.execPtraceFunc(func() {
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debugregs := make([]uint64, 8)
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for i := range debugregs {
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if i == 4 || i == 5 {
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continue
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}
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_, _, err = sys.Syscall6(sys.SYS_PTRACE, sys.PTRACE_PEEKUSR, uintptr(t.ID), uintptr(debugRegUserOffset+uintptr(i)*unsafe.Sizeof(debugregs[0])), uintptr(unsafe.Pointer(&debugregs[i])), 0, 0)
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if err != nil && err != syscall.Errno(0) {
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return
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}
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}
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drs := amd64util.NewDebugRegisters(&debugregs[0], &debugregs[1], &debugregs[2], &debugregs[3], &debugregs[6], &debugregs[7])
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err = f(drs)
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if drs.Dirty {
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for i := range debugregs {
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if i == 4 || i == 5 {
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// Linux will return EIO for DR4 and DR5
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continue
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}
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_, _, err = sys.Syscall6(sys.SYS_PTRACE, sys.PTRACE_POKEUSR, uintptr(t.ID), uintptr(debugRegUserOffset+uintptr(i)*unsafe.Sizeof(debugregs[0])), uintptr(debugregs[i]), 0, 0)
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if err != nil && err != syscall.Errno(0) {
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return
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}
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}
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}
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})
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if err == syscall.Errno(0) || err == sys.ESRCH {
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err = nil
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}
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return err
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}
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func (t *nativeThread) writeHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
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return t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
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return drs.SetBreakpoint(idx, addr, wtype.Read(), wtype.Write(), wtype.Size())
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})
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}
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func (t *nativeThread) clearHardwareBreakpoint(addr uint64, wtype proc.WatchType, idx uint8) error {
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return t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
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drs.ClearBreakpoint(idx)
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return nil
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})
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}
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func (t *nativeThread) findHardwareBreakpoint() (*proc.Breakpoint, error) {
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var retbp *proc.Breakpoint
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err := t.withDebugRegisters(func(drs *amd64util.DebugRegisters) error {
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ok, idx := drs.GetActiveBreakpoint()
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if ok {
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for _, bp := range t.dbp.Breakpoints().M {
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if bp.WatchType != 0 && bp.HWBreakIndex == idx {
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retbp = bp
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break
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}
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}
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}
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return nil
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})
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if err != nil {
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return nil, err
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}
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return retbp, nil
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}
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