| // Copyright 2014 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package runtime |
| |
| import ( |
| "runtime/internal/sys" |
| "unsafe" |
| ) |
| |
| // cbs stores all registered Go callbacks. |
| var cbs struct { |
| lock mutex |
| ctxt [cb_max]winCallback |
| index map[winCallbackKey]int |
| n int |
| } |
| |
| // winCallback records information about a registered Go callback. |
| type winCallback struct { |
| fn *funcval // Go function |
| retPop uintptr // For 386 cdecl, how many bytes to pop on return |
| |
| // abiMap specifies how to translate from a C frame to a Go |
| // frame. This does not specify how to translate back because |
| // the result is always a uintptr. If the C ABI is fastcall, |
| // this assumes the four fastcall registers were first spilled |
| // to the shadow space. |
| abiMap []abiPart |
| // retOffset is the offset of the uintptr-sized result in the Go |
| // frame. |
| retOffset uintptr |
| } |
| |
| // abiPart encodes a step in translating between calling ABIs. |
| type abiPart struct { |
| src, dst uintptr |
| len uintptr |
| } |
| |
| func (a *abiPart) tryMerge(b abiPart) bool { |
| if a.src+a.len == b.src && a.dst+a.len == b.dst { |
| a.len += b.len |
| return true |
| } |
| return false |
| } |
| |
| type winCallbackKey struct { |
| fn *funcval |
| cdecl bool |
| } |
| |
| func callbackasm() |
| |
| // callbackasmAddr returns address of runtime.callbackasm |
| // function adjusted by i. |
| // On x86 and amd64, runtime.callbackasm is a series of CALL instructions, |
| // and we want callback to arrive at |
| // correspondent call instruction instead of start of |
| // runtime.callbackasm. |
| // On ARM, runtime.callbackasm is a series of mov and branch instructions. |
| // R12 is loaded with the callback index. Each entry is two instructions, |
| // hence 8 bytes. |
| func callbackasmAddr(i int) uintptr { |
| var entrySize int |
| switch GOARCH { |
| default: |
| panic("unsupported architecture") |
| case "386", "amd64": |
| entrySize = 5 |
| case "arm": |
| // On ARM, each entry is a MOV instruction |
| // followed by a branch instruction |
| entrySize = 8 |
| } |
| return funcPC(callbackasm) + uintptr(i*entrySize) |
| } |
| |
| const callbackMaxFrame = 64 * sys.PtrSize |
| |
| // compileCallback converts a Go function fn into a C function pointer |
| // that can be passed to Windows APIs. |
| // |
| // On 386, if cdecl is true, the returned C function will use the |
| // cdecl calling convention; otherwise, it will use stdcall. On amd64, |
| // it always uses fastcall. On arm, it always uses the ARM convention. |
| // |
| //go:linkname compileCallback syscall.compileCallback |
| func compileCallback(fn eface, cdecl bool) (code uintptr) { |
| if GOARCH != "386" { |
| // cdecl is only meaningful on 386. |
| cdecl = false |
| } |
| |
| if fn._type == nil || (fn._type.kind&kindMask) != kindFunc { |
| panic("compileCallback: expected function with one uintptr-sized result") |
| } |
| ft := (*functype)(unsafe.Pointer(fn._type)) |
| |
| // Check arguments and construct ABI translation. |
| var abiMap []abiPart |
| var src, dst uintptr |
| for _, t := range ft.in() { |
| if t.size > sys.PtrSize { |
| // We don't support this right now. In |
| // stdcall/cdecl, 64-bit ints and doubles are |
| // passed as two words (little endian); and |
| // structs are pushed on the stack. In |
| // fastcall, arguments larger than the word |
| // size are passed by reference. |
| panic("compileCallback: argument size is larger than uintptr") |
| } |
| if k := t.kind & kindMask; GOARCH == "amd64" && (k == kindFloat32 || k == kindFloat64) { |
| // In fastcall, floating-point arguments in |
| // the first four positions are passed in |
| // floating-point registers, which we don't |
| // currently spill. |
| panic("compileCallback: float arguments not supported") |
| } |
| |
| // The Go ABI aligns arguments. |
| dst = alignUp(dst, uintptr(t.align)) |
| // In the C ABI, we're already on a word boundary. |
| // Also, sub-word-sized fastcall register arguments |
| // are stored to the least-significant bytes of the |
| // argument word and all supported Windows |
| // architectures are little endian, so src is already |
| // pointing to the right place for smaller arguments. |
| |
| // Copy just the size of the argument. Note that this |
| // could be a small by-value struct, but C and Go |
| // struct layouts are compatible, so we can copy these |
| // directly, too. |
| part := abiPart{src, dst, t.size} |
| // Add this step to the adapter. |
| if len(abiMap) == 0 || !abiMap[len(abiMap)-1].tryMerge(part) { |
| abiMap = append(abiMap, part) |
| } |
| |
| // cdecl, stdcall, and fastcall pad arguments to word size. |
| src += sys.PtrSize |
| // The Go ABI packs arguments. |
| dst += t.size |
| } |
| // The Go ABI aligns the result to the word size. src is |
| // already aligned. |
| dst = alignUp(dst, sys.PtrSize) |
| retOffset := dst |
| |
| if len(ft.out()) != 1 { |
| panic("compileCallback: expected function with one uintptr-sized result") |
| } |
| if ft.out()[0].size != sys.PtrSize { |
| panic("compileCallback: expected function with one uintptr-sized result") |
| } |
| if k := ft.out()[0].kind & kindMask; k == kindFloat32 || k == kindFloat64 { |
| // In cdecl and stdcall, float results are returned in |
| // ST(0). In fastcall, they're returned in XMM0. |
| // Either way, it's not AX. |
| panic("compileCallback: float results not supported") |
| } |
| // Make room for the uintptr-sized result. |
| dst += sys.PtrSize |
| |
| if dst > callbackMaxFrame { |
| panic("compileCallback: function argument frame too large") |
| } |
| |
| // For cdecl, the callee is responsible for popping its |
| // arguments from the C stack. |
| var retPop uintptr |
| if cdecl { |
| retPop = src |
| } |
| |
| key := winCallbackKey{(*funcval)(fn.data), cdecl} |
| |
| lock(&cbs.lock) // We don't unlock this in a defer because this is used from the system stack. |
| |
| // Check if this callback is already registered. |
| if n, ok := cbs.index[key]; ok { |
| unlock(&cbs.lock) |
| return callbackasmAddr(n) |
| } |
| |
| // Register the callback. |
| if cbs.index == nil { |
| cbs.index = make(map[winCallbackKey]int) |
| } |
| n := cbs.n |
| if n >= len(cbs.ctxt) { |
| unlock(&cbs.lock) |
| throw("too many callback functions") |
| } |
| c := winCallback{key.fn, retPop, abiMap, retOffset} |
| cbs.ctxt[n] = c |
| cbs.index[key] = n |
| cbs.n++ |
| |
| unlock(&cbs.lock) |
| return callbackasmAddr(n) |
| } |
| |
| type callbackArgs struct { |
| index uintptr |
| args unsafe.Pointer // Arguments in stdcall/cdecl convention, with registers spilled |
| // Below are out-args from callbackWrap |
| result uintptr |
| retPop uintptr // For 386 cdecl, how many bytes to pop on return |
| } |
| |
| // callbackWrap is called by callbackasm to invoke a registered C callback. |
| func callbackWrap(a *callbackArgs) { |
| c := cbs.ctxt[a.index] |
| a.retPop = c.retPop |
| |
| // Convert from stdcall to Go ABI. |
| var frame [callbackMaxFrame]byte |
| goArgs := unsafe.Pointer(&frame) |
| for _, part := range c.abiMap { |
| memmove(add(goArgs, part.dst), add(a.args, part.src), part.len) |
| } |
| |
| // Even though this is copying back results, we can pass a nil |
| // type because those results must not require write barriers. |
| reflectcall(nil, unsafe.Pointer(c.fn), noescape(goArgs), uint32(c.retOffset)+sys.PtrSize, uint32(c.retOffset)) |
| |
| // Extract the result. |
| a.result = *(*uintptr)(unsafe.Pointer(&frame[c.retOffset])) |
| } |
| |
| const _LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800 |
| |
| // When available, this function will use LoadLibraryEx with the filename |
| // parameter and the important SEARCH_SYSTEM32 argument. But on systems that |
| // do not have that option, absoluteFilepath should contain a fallback |
| // to the full path inside of system32 for use with vanilla LoadLibrary. |
| //go:linkname syscall_loadsystemlibrary syscall.loadsystemlibrary |
| //go:nosplit |
| func syscall_loadsystemlibrary(filename *uint16, absoluteFilepath *uint16) (handle, err uintptr) { |
| lockOSThread() |
| c := &getg().m.syscall |
| |
| if useLoadLibraryEx { |
| c.fn = getLoadLibraryEx() |
| c.n = 3 |
| args := struct { |
| lpFileName *uint16 |
| hFile uintptr // always 0 |
| flags uint32 |
| }{filename, 0, _LOAD_LIBRARY_SEARCH_SYSTEM32} |
| c.args = uintptr(noescape(unsafe.Pointer(&args))) |
| } else { |
| c.fn = getLoadLibrary() |
| c.n = 1 |
| c.args = uintptr(noescape(unsafe.Pointer(&absoluteFilepath))) |
| } |
| |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| handle = c.r1 |
| if handle == 0 { |
| err = c.err |
| } |
| unlockOSThread() // not defer'd after the lockOSThread above to save stack frame size. |
| return |
| } |
| |
| //go:linkname syscall_loadlibrary syscall.loadlibrary |
| //go:nosplit |
| func syscall_loadlibrary(filename *uint16) (handle, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = getLoadLibrary() |
| c.n = 1 |
| c.args = uintptr(noescape(unsafe.Pointer(&filename))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| handle = c.r1 |
| if handle == 0 { |
| err = c.err |
| } |
| return |
| } |
| |
| //go:linkname syscall_getprocaddress syscall.getprocaddress |
| //go:nosplit |
| func syscall_getprocaddress(handle uintptr, procname *byte) (outhandle, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = getGetProcAddress() |
| c.n = 2 |
| c.args = uintptr(noescape(unsafe.Pointer(&handle))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| outhandle = c.r1 |
| if outhandle == 0 { |
| err = c.err |
| } |
| return |
| } |
| |
| //go:linkname syscall_Syscall syscall.Syscall |
| //go:nosplit |
| func syscall_Syscall(fn, nargs, a1, a2, a3 uintptr) (r1, r2, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = fn |
| c.n = nargs |
| c.args = uintptr(noescape(unsafe.Pointer(&a1))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| return c.r1, c.r2, c.err |
| } |
| |
| //go:linkname syscall_Syscall6 syscall.Syscall6 |
| //go:nosplit |
| func syscall_Syscall6(fn, nargs, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = fn |
| c.n = nargs |
| c.args = uintptr(noescape(unsafe.Pointer(&a1))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| return c.r1, c.r2, c.err |
| } |
| |
| //go:linkname syscall_Syscall9 syscall.Syscall9 |
| //go:nosplit |
| func syscall_Syscall9(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = fn |
| c.n = nargs |
| c.args = uintptr(noescape(unsafe.Pointer(&a1))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| return c.r1, c.r2, c.err |
| } |
| |
| //go:linkname syscall_Syscall12 syscall.Syscall12 |
| //go:nosplit |
| func syscall_Syscall12(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12 uintptr) (r1, r2, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = fn |
| c.n = nargs |
| c.args = uintptr(noescape(unsafe.Pointer(&a1))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| return c.r1, c.r2, c.err |
| } |
| |
| //go:linkname syscall_Syscall15 syscall.Syscall15 |
| //go:nosplit |
| func syscall_Syscall15(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15 uintptr) (r1, r2, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = fn |
| c.n = nargs |
| c.args = uintptr(noescape(unsafe.Pointer(&a1))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| return c.r1, c.r2, c.err |
| } |
| |
| //go:linkname syscall_Syscall18 syscall.Syscall18 |
| //go:nosplit |
| func syscall_Syscall18(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18 uintptr) (r1, r2, err uintptr) { |
| lockOSThread() |
| defer unlockOSThread() |
| c := &getg().m.syscall |
| c.fn = fn |
| c.n = nargs |
| c.args = uintptr(noescape(unsafe.Pointer(&a1))) |
| cgocall(asmstdcallAddr, unsafe.Pointer(c)) |
| return c.r1, c.r2, c.err |
| } |