pky/proc: enable function call injection in Delve for linux/ppc64le (#3449)

* enable func call injection on delve for ppc64le

* Function call injection on Delve/ppc64le, modified DWARF encoding and decoding for floating point registers to make floatsum test work

* Function call injection on Delve/ppc64le cleanup

* skip PIE tests for function call injection on other packages

* Address review comments

* accounted for additional skipped PIE tests for function call injection

* Code cleanup and undoing revert of previous commit

* Enable function call injection only on 1.22 and above and some cleanup

* additional cleanup, go fmt run

* Debug function call tests fail on ppc64le/PIE mode adjusted the backup_test_health.md file accordingly

Documentation/backend_test_health.md

@@ -20,6 +20,8 @@ Tests skipped by each supported backend:
 	* 1 broken - cgo stacktraces
 * linux/ppc64le/native skipped = 1
 	* 1 broken in linux ppc64le
+* linux/ppc64le/native/pie skipped = 3
+	* 3 broken - pie mode
 * pie skipped = 2
 	* 2 upstream issue - https://github.com/golang/go/issues/29322
 * ppc64le skipped = 11

pkg/dwarf/regnum/ppc64le.go

@@ -17,13 +17,14 @@ const (
 	PPC64LE_F0        = PPC64LE_FIRST_FPR
 	PPC64LE_LAST_FPR  = 63
 	// Vector (Altivec/VMX) registers: from V0 to V31
-	PPC64LE_FIRST_VMX = 64
+	PPC64LE_FIRST_VMX = 77
 	PPC64LE_V0        = PPC64LE_FIRST_VMX
-	PPC64LE_LAST_VMX  = 95
+	PPC64LE_LAST_VMX  = 108
-	// Vector Scalar (VSX) registers: from VS0 to VS63
+	// Vector Scalar (VSX) registers: from VS32 to VS63
-	PPC64LE_FIRST_VSX = 96
+	// On ppc64le these are mapped to F0 to F31
+	PPC64LE_FIRST_VSX = 32
 	PPC64LE_VS0       = PPC64LE_FIRST_VSX
-	PPC64LE_LAST_VSX  = 160
+	PPC64LE_LAST_VSX  = 63
 	// Condition Registers: from CR0 to CR7
 	PPC64LE_CR0 = 0
 	// Special registers

pkg/proc/fncall.go

@@ -336,10 +336,16 @@ func evalFunctionCall(scope *EvalScope, node *ast.CallExpr) (*Variable, error) {
 		if err := writePointer(bi, scope.Mem, regs.SP()-3*uint64(bi.Arch.PtrSize()), uint64(fncall.argFrameSize)); err != nil {
 			return nil, err
 		}
-	case "arm64":
+	case "arm64", "ppc64le":
 		// debugCallV2 on arm64 needs a special call sequence, callOP can not be used
 		sp := regs.SP()
-		sp -= 2 * uint64(bi.Arch.PtrSize())
+		var spOffset uint64
+		if bi.Arch.Name == "arm64" {
+			spOffset = 2 * uint64(bi.Arch.PtrSize())
+		} else {
+			spOffset = 4 * uint64(bi.Arch.PtrSize())
+		}
+		sp -= spOffset
 		if err := setSP(thread, sp); err != nil {
 			return nil, err
 		}
@@ -349,7 +355,7 @@ func evalFunctionCall(scope *EvalScope, node *ast.CallExpr) (*Variable, error) {
 		if err := setLR(thread, regs.PC()); err != nil {
 			return nil, err
 		}
-		if err := writePointer(bi, scope.Mem, sp-uint64(2*bi.Arch.PtrSize()), uint64(fncall.argFrameSize)); err != nil {
+		if err := writePointer(bi, scope.Mem, sp-spOffset, uint64(fncall.argFrameSize)); err != nil {
 			return nil, err
 		}
 		regs, err = thread.Registers()
@@ -365,6 +371,7 @@ func evalFunctionCall(scope *EvalScope, node *ast.CallExpr) (*Variable, error) {
 		if err != nil {
 			return nil, err
 		}
+
 	}
 
 	fncallLog("function call initiated %v frame size %d goroutine %d (thread %d)", fncall.fn, fncall.argFrameSize, scope.g.ID, thread.ThreadID())
@@ -483,11 +490,12 @@ func callOP(bi *BinaryInfo, thread Thread, regs Registers, callAddr uint64) erro
 			return err
 		}
 		return setPC(thread, callAddr)
-	case "arm64":
+	case "arm64", "ppc64le":
 		if err := setLR(thread, regs.PC()); err != nil {
 			return err
 		}
 		return setPC(thread, callAddr)
+
 	default:
 		panic("not implemented")
 	}
@@ -864,6 +872,8 @@ func funcCallStep(callScope *EvalScope, fncall *functionCallState, thread Thread
 		archoff := uint64(0)
 		if bi.Arch.Name == "arm64" {
 			archoff = 8
+		} else if bi.Arch.Name == "ppc64le" {
+			archoff = 40
 		}
 		// get error from top of the stack and return it to user
 		errvar, err := readStackVariable(p, thread, regs, archoff, "string", loadFullValue)
@@ -912,7 +922,7 @@ func funcCallStep(callScope *EvalScope, fncall *functionCallState, thread Thread
 		cfa := regs.SP()
 		oldpc := regs.PC()
 		var oldlr uint64
-		if bi.Arch.Name == "arm64" {
+		if bi.Arch.Name == "arm64" || bi.Arch.Name == "ppc64le" {
 			oldlr = regs.LR()
 		}
 		callOP(bi, thread, regs, fncall.fn.Entry)
@@ -925,7 +935,7 @@ func funcCallStep(callScope *EvalScope, fncall *functionCallState, thread Thread
 			case "amd64":
 				setSP(thread, cfa)
 				setPC(thread, oldpc)
-			case "arm64":
+			case "arm64", "ppc64le":
 				setLR(thread, oldlr)
 				setPC(thread, oldpc)
 			default:
@@ -1006,7 +1016,7 @@ func funcCallStep(callScope *EvalScope, fncall *functionCallState, thread Thread
 		if threadg, _ := GetG(thread); threadg != nil {
 			callScope.callCtx.stacks = append(callScope.callCtx.stacks, threadg.stack)
 		}
-		if bi.Arch.Name == "arm64" {
+		if bi.Arch.Name == "arm64" || bi.Arch.Name == "ppc64le" {
 			oldlr, err := readUintRaw(thread.ProcessMemory(), regs.SP(), int64(bi.Arch.PtrSize()))
 			if err != nil {
 				fncall.err = fmt.Errorf("could not restore LR: %v", err)
@@ -1023,6 +1033,8 @@ func funcCallStep(callScope *EvalScope, fncall *functionCallState, thread Thread
 		archoff := uint64(0)
 		if bi.Arch.Name == "arm64" {
 			archoff = 8
+		} else if bi.Arch.Name == "ppc64le" {
+			archoff = 32
 		}
 		fncall.panicvar, err = readStackVariable(p, thread, regs, archoff, "interface {}", callScope.callCtx.retLoadCfg)
 		if err != nil {
@@ -1068,7 +1080,6 @@ func fakeFunctionEntryScope(scope *EvalScope, fn *Function, cfa int64, sp uint64
 	scope.PC = fn.Entry
 	scope.Fn = fn
 	scope.File, scope.Line = scope.BinInfo.EntryLineForFunc(fn)
-
 	scope.Regs.CFA = cfa
 	scope.Regs.Reg(scope.Regs.SPRegNum).Uint64Val = sp
 	scope.Regs.Reg(scope.Regs.PCRegNum).Uint64Val = fn.Entry
@@ -1260,7 +1271,7 @@ func debugCallProtocolReg(archName string, version int) (uint64, bool) {
 			return 0, false
 		}
 		return protocolReg, true
-	case "arm64":
+	case "arm64", "ppc64le":
 		if version == 2 {
 			return regnum.ARM64_X0 + 20, true
 		}
@@ -1335,6 +1346,15 @@ func regabiMallocgcWorkaround(bi *BinaryInfo) ([]*godwarf.Tree, error) {
 			m("~r1", t("unsafe.Pointer"), regnum.ARM64_X0, true),
 		}
 		return r, err1
+	case "ppc64le":
+		r := []*godwarf.Tree{
+			m("size", t("uintptr"), regnum.PPC64LE_R0+3, false),
+			m("typ", t(ptrToRuntimeType), regnum.PPC64LE_R0+4, false),
+			m("needzero", t("bool"), regnum.PPC64LE_R0+5, false),
+			m("~r1", t("unsafe.Pointer"), regnum.PPC64LE_R0+3, true),
+		}
+		return r, err1
+
 	default:
 		// do nothing
 		return nil, nil

pkg/proc/linutil/regs_ppc64le_arch.go

@@ -3,6 +3,8 @@ package linutil
 import (
 	"fmt"
 
+	"github.com/go-delve/delve/pkg/dwarf/op"
+	"github.com/go-delve/delve/pkg/dwarf/regnum"
 	"github.com/go-delve/delve/pkg/proc"
 )
 
@@ -162,13 +164,51 @@ func (r *PPC64LERegisters) Copy() (proc.Registers, error) {
 	return &rr, nil
 }
 
+func (r *PPC64LERegisters) SetReg(regNum uint64, reg *op.DwarfRegister) (fpchanged bool, err error) {
+	switch regNum {
+	case regnum.PPC64LE_PC:
+		r.Regs.Nip = reg.Uint64Val
+		return false, nil
+	case regnum.PPC64LE_LR:
+		r.Regs.Link = reg.Uint64Val
+		return false, nil
+	case regnum.PPC64LE_SP:
+		r.Regs.Gpr[1] = reg.Uint64Val
+		return false, nil
+	default:
+		switch {
+		case regNum >= regnum.PPC64LE_R0 && regNum <= regnum.PPC64LE_R0+31:
+			r.Regs.Gpr[regNum-regnum.PPC64LE_R0] = reg.Uint64Val
+			return false, nil
+
+		case regNum >= regnum.PPC64LE_F0 && regNum <= regnum.PPC64LE_F0+31:
+			if r.loadFpRegs != nil {
+				err := r.loadFpRegs(r)
+				r.loadFpRegs = nil
+				if err != nil {
+					return false, err
+				}
+			}
+			// On ppc64le, PPC64LE_VS0 .. PPC64LE_VS31 are mapped onto
+			// PPC64LE_F0 .. PPC64LE_F31
+			i := regNum - regnum.PPC64LE_VS0
+			reg.FillBytes()
+			copy(r.Fpregset[8*i:], reg.Bytes)
+			return true, nil
+
+		default:
+			return false, fmt.Errorf("changing register %d not implemented", regNum)
+		}
+	}
+}
+
 type PPC64LEPtraceFpRegs struct {
 	Fp []byte
 }
 
 func (fpregs *PPC64LEPtraceFpRegs) Decode() (regs []proc.Register) {
-	for i := 0; i < len(fpregs.Fp); i += 16 {
+	for i := 0; i < len(fpregs.Fp); i += 8 {
-		regs = proc.AppendBytesRegister(regs, fmt.Sprintf("V%d", i/16), fpregs.Fp[i:i+16])
+		regs = proc.AppendBytesRegister(regs, fmt.Sprintf("VS%d", i/8), fpregs.Fp[i:i+8])
 	}
 	return
 }

pkg/proc/native/registers_linux_ppc64le.go

@@ -6,7 +6,6 @@ import (
 	"unsafe"
 
 	"github.com/go-delve/delve/pkg/dwarf/op"
-	"github.com/go-delve/delve/pkg/dwarf/regnum"
 	"github.com/go-delve/delve/pkg/proc"
 	"github.com/go-delve/delve/pkg/proc/linutil"
 	sys "golang.org/x/sys/unix"
@@ -63,25 +62,30 @@ func (t *nativeThread) setPC(pc uint64) error {
 }
 
 // SetReg changes the value of the specified register.
-func (t *nativeThread) SetReg(regNum uint64, reg *op.DwarfRegister) error {
+func (thread *nativeThread) SetReg(regNum uint64, reg *op.DwarfRegister) error {
-	ir, err := registers(t)
+	ir, err := registers(thread)
 	if err != nil {
 		return err
 	}
 	r := ir.(*linutil.PPC64LERegisters)
 
-	switch regNum {
+	fpchanged, err := r.SetReg(regNum, reg)
-	case regnum.PPC64LE_PC:
+	if err != nil {
-		r.Regs.Nip = reg.Uint64Val
+		return err
-	case regnum.PPC64LE_SP:
+	}
-		r.Regs.Gpr[1] = reg.Uint64Val
+	thread.dbp.execPtraceFunc(func() {
-	case regnum.PPC64LE_LR:
+		err = ptraceSetGRegs(thread.ID, r.Regs)
-		r.Regs.Link = reg.Uint64Val
+		if err != syscall.Errno(0) && err != nil {
-	default:
+			return
-		panic("SetReg")
+		}
+		if fpchanged && r.Fpregset != nil {
+			iov := sys.Iovec{Base: &r.Fpregset[0], Len: uint64(len(r.Fpregset))}
+			_, _, err = syscall.Syscall6(syscall.SYS_PTRACE, sys.PTRACE_SETREGSET, uintptr(thread.ID), uintptr(elf.NT_FPREGSET), uintptr(unsafe.Pointer(&iov)), 0, 0)
+		}
+	})
+	if err == syscall.Errno(0) {
+		err = nil
 	}
-
-	t.dbp.execPtraceFunc(func() { err = ptraceSetGRegs(t.ID, r.Regs) })
 	return err
 }
 

pkg/proc/native/threads_linux_ppc64le.go

@@ -2,6 +2,12 @@ package native
 
 import (
 	"fmt"
+	"debug/elf"
+        "syscall"
+        "unsafe"
+
+        sys "golang.org/x/sys/unix"
+
 
 	"github.com/go-delve/delve/pkg/proc"
 	"github.com/go-delve/delve/pkg/proc/linutil"
@@ -21,5 +27,22 @@ func (t *nativeThread) fpRegisters() ([]proc.Register, []byte, error) {
 }
 
 func (t *nativeThread) restoreRegisters(savedRegs proc.Registers) error {
-	panic("Unimplemented restoreRegisters method in threads_linux_ppc64le.go")
+        sr := savedRegs.(*linutil.PPC64LERegisters)
+
+        var restoreRegistersErr error
+        t.dbp.execPtraceFunc(func() {
+                restoreRegistersErr = ptraceSetGRegs(t.ID, sr.Regs)
+                if restoreRegistersErr != syscall.Errno(0) && restoreRegistersErr != nil {
+                        return
+                }
+                if sr.Fpregset != nil {
+                        iov := sys.Iovec{Base: &sr.Fpregset[0], Len: _PPC64LE_FPREGS_SIZE}
+                        _, _, restoreRegistersErr = syscall.Syscall6(syscall.SYS_PTRACE, sys.PTRACE_SETREGSET, uintptr(t.ID), uintptr(elf.NT_FPREGSET), uintptr(unsafe.Pointer(&iov)), 0, 0)
+                }
+        })
+        if restoreRegistersErr == syscall.Errno(0) {
+                restoreRegistersErr = nil
+        }
+        return restoreRegistersErr
 }
+

pkg/proc/ppc64le_arch.go

@@ -35,9 +35,12 @@ func PPC64LEArch(goos string) *Arch {
 		usesLR:                           true,
 		PCRegNum:                         regnum.PPC64LE_PC,
 		SPRegNum:                         regnum.PPC64LE_SP,
+		ContextRegNum:                    regnum.PPC64LE_R0 + 11,
 		LRRegNum:                         regnum.PPC64LE_LR,
 		asmRegisters:                     ppc64leAsmRegisters,
 		RegisterNameToDwarf:              nameToDwarfFunc(regnum.PPC64LENameToDwarf),
+		debugCallMinStackSize:            320,
+		maxRegArgBytes:                   13*8 + 13*8,
 	}
 }
 

pkg/proc/proc_test.go

@@ -4312,6 +4312,8 @@ func TestReadDeferArgs(t *testing.T) {
 
 func TestIssue1374(t *testing.T) {
 	// Continue did not work when stopped at a breakpoint immediately after calling CallFunction.
+	skipOn(t, "broken - pie mode", "linux", "ppc64le", "native", "pie")
+
 	protest.MustSupportFunctionCalls(t, testBackend)
 	withTestProcess("issue1374", t, func(p *proc.Target, grp *proc.TargetGroup, fixture protest.Fixture) {
 		setFileBreakpoint(p, t, fixture.Source, 7)
@@ -4537,6 +4539,8 @@ func testCallConcurrentCheckReturns(p *proc.Target, t *testing.T, gid1, gid2 int
 }
 
 func TestCallConcurrent(t *testing.T) {
+	skipOn(t, "broken - pie mode", "linux", "ppc64le", "native", "pie")
+
 	protest.MustSupportFunctionCalls(t, testBackend)
 	withTestProcess("teststepconcurrent", t, func(p *proc.Target, grp *proc.TargetGroup, fixture protest.Fixture) {
 		bp := setFileBreakpoint(p, t, fixture.Source, 24)
@@ -4932,6 +4936,7 @@ func TestIssue1925(t *testing.T) {
 	// In particular the stepInstructionOut function called at the end of a
 	// 'call' procedure should clean the G cache like every other function
 	// altering the state of the target process.
+	skipOn(t, "broken - pie mode", "linux", "ppc64le", "native", "pie")
 	protest.MustSupportFunctionCalls(t, testBackend)
 	withTestProcess("testvariables2", t, func(p *proc.Target, grp *proc.TargetGroup, fixture protest.Fixture) {
 		assertNoError(grp.Continue(), t, "Continue()")

pkg/proc/target.go

@@ -252,7 +252,7 @@ func (t *Target) Valid() (bool, error) {
 // Currently only non-recorded processes running on AMD64 support
 // function calls.
 func (t *Target) SupportsFunctionCalls() bool {
-	return t.Process.BinInfo().Arch.Name == "amd64" || (t.Process.BinInfo().Arch.Name == "arm64" && t.Process.BinInfo().GOOS != "windows")
+	return t.Process.BinInfo().Arch.Name == "amd64" || (t.Process.BinInfo().Arch.Name == "arm64" && t.Process.BinInfo().GOOS != "windows") || t.Process.BinInfo().Arch.Name == "ppc64le"
 }
 
 // ClearCaches clears internal caches that should not survive a restart.

pkg/proc/test/support.go

@@ -310,7 +310,7 @@ func MustSupportFunctionCalls(t *testing.T, testBackend string) {
 	if runtime.GOOS == "darwin" && os.Getenv("TRAVIS") == "true" && runtime.GOARCH == "amd64" {
 		t.Skip("function call injection tests are failing on macOS on Travis-CI (see #1802)")
 	}
-	if runtime.GOARCH == "386" || runtime.GOARCH == "ppc64le" {
+	if runtime.GOARCH == "386" {
 		t.Skip(fmt.Errorf("%s does not support FunctionCall for now", runtime.GOARCH))
 	}
 	if runtime.GOARCH == "arm64" {
@@ -318,6 +318,12 @@ func MustSupportFunctionCalls(t *testing.T, testBackend string) {
 			t.Skip("this version of Go does not support function calls")
 		}
 	}
+
+	if runtime.GOARCH == "ppc64le" {
+		if !goversion.VersionAfterOrEqual(runtime.Version(), 1, 22) {
+			t.Skip("On PPC64LE Building with Go lesser than 1.22 does not support function calls")
+		}
+	}
 }
 
 // DefaultTestBackend changes the value of testBackend to be the default

pkg/proc/variables_test.go

@@ -1158,6 +1158,8 @@ type testCaseCallFunction struct {
 }
 
 func TestCallFunction(t *testing.T) {
+	skipOn(t, "broken - pie mode", "linux", "ppc64le", "native", "pie")
+
 	protest.MustSupportFunctionCalls(t, testBackend)
 	protest.AllowRecording(t)
 
@@ -1289,6 +1291,7 @@ func TestCallFunction(t *testing.T) {
 		testCallFunctionSetBreakpoint(t, p, grp, fixture)
 
 		assertNoError(grp.Continue(), t, "Continue()")
+
 		for _, tc := range testcases {
 			testCallFunction(t, grp, p, tc)
 		}

pkg/terminal/command_test.go

@@ -996,6 +996,9 @@ func findStarFile(name string) string {
 }
 
 func TestIssue1598(t *testing.T) {
+	if buildMode == "pie" && runtime.GOARCH == "ppc64le" {
+		t.Skip("Debug function call Test broken in PIE mode")
+	}
 	test.MustSupportFunctionCalls(t, testBackend)
 	withTestTerminal("issue1598", t, func(term *FakeTerminal) {
 		term.MustExec("break issue1598.go:5")

service/test/integration2_test.go

@@ -2109,6 +2109,10 @@ func TestForceStopWhileContinue(t *testing.T) {
 }
 
 func TestClientServerFunctionCall(t *testing.T) {
+	if buildMode == "pie" && runtime.GOARCH == "ppc64le" {
+		t.Skip("Debug function call Test broken in PIE mode")
+	}
+
 	protest.MustSupportFunctionCalls(t, testBackend)
 	withTestClient2("fncall", t, func(c service.Client) {
 		c.SetReturnValuesLoadConfig(&normalLoadConfig)
@@ -2139,6 +2143,9 @@ func TestClientServerFunctionCall(t *testing.T) {
 }
 
 func TestClientServerFunctionCallPanic(t *testing.T) {
+	if buildMode == "pie" && runtime.GOARCH == "ppc64le" {
+		t.Skip("Debug function call Test broken in PIE mode")
+	}
 	protest.MustSupportFunctionCalls(t, testBackend)
 	withTestClient2("fncall", t, func(c service.Client) {
 		c.SetReturnValuesLoadConfig(&normalLoadConfig)