defs_windows_arm64.go

     1  // Copyright 2025 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package windows
     6  
     7  import (
     8  	"internal/goarch"
     9  	"unsafe"
    10  )
    11  
    12  // NOTE(rsc): CONTEXT_CONTROL is actually 0x400001 and should include PC, SP, and LR.
    13  // However, empirically, LR doesn't come along on Windows 10
    14  // unless you also set CONTEXT_INTEGER (0x400002).
    15  // Without LR, we skip over the next-to-bottom function in profiles
    16  // when the bottom function is frameless.
    17  // So we set both here, to make a working CONTEXT_CONTROL.
    18  const CONTEXT_CONTROL = 0x400003
    19  
    20  type Neon128 struct {
    21  	Low  uint64
    22  	High int64
    23  }
    24  
    25  // See https://docs.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-arm64_nt_context
    26  type Context struct {
    27  	ContextFlags uint32
    28  	Cpsr         uint32
    29  	X            [31]uint64 // fp is x[29], lr is x[30]
    30  	XSp          uint64
    31  	Pc           uint64
    32  	V            [32]Neon128
    33  	Fpcr         uint32
    34  	Fpsr         uint32
    35  	Bcr          [8]uint32
    36  	Bvr          [8]uint64
    37  	Wcr          [2]uint32
    38  	Wvr          [2]uint64
    39  }
    40  
    41  func (c *Context) PC() uintptr { return uintptr(c.Pc) }
    42  func (c *Context) SP() uintptr { return uintptr(c.XSp) }
    43  func (c *Context) LR() uintptr { return uintptr(c.X[30]) }
    44  
    45  func (c *Context) SetPC(x uintptr) { c.Pc = uint64(x) }
    46  func (c *Context) SetSP(x uintptr) { c.XSp = uint64(x) }
    47  func (c *Context) SetLR(x uintptr) { c.X[30] = uint64(x) }
    48  func (c *Context) SetFP(x uintptr) { c.X[29] = uint64(x) }
    49  
    50  func (c *Context) PushCall(targetPC, resumePC uintptr) {
    51  	// Push LR. The injected call is responsible
    52  	// for restoring LR. gentraceback is aware of
    53  	// this extra slot. See sigctxt.pushCall in
    54  	// signal_arm64.go.
    55  	sp := c.SP() - goarch.StackAlign
    56  	c.SetSP(sp)
    57  	*(*uint64)(unsafe.Pointer(sp)) = uint64(c.LR())
    58  	c.SetLR(resumePC)
    59  	c.SetPC(targetPC)
    60  }
    61  
    62  type DISPATCHER_CONTEXT struct {
    63  	ControlPc        uint64
    64  	ImageBase        uint64
    65  	FunctionEntry    uintptr
    66  	EstablisherFrame uint64
    67  	TargetIp         uint64
    68  	Context          *Context
    69  	LanguageHandler  uintptr
    70  	HandlerData      uintptr
    71  }
    72  
    73  func (c *DISPATCHER_CONTEXT) Ctx() *Context {
    74  	return c.Context
    75  }
    76
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