2c4ae3b0a4
Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для неё не нужна. Module path github.com/sagernet/gvisor сохранён намеренно: на него опирается replace-директива суперпроекта. Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show и переносилась на новый пин копированием. SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH
114 lines
3.1 KiB
Go
114 lines
3.1 KiB
Go
// Copyright 2022 The gVisor Authors.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd.
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package hostarch
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// Masks often used when working with alignment in constant expressions.
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const (
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PageMask = PageSize - 1
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HugePageMask = HugePageSize - 1
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CacheLineMask = CacheLineSize - 1
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)
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type bytecount interface {
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~uint | ~uint16 | ~uint32 | ~uint64 | ~uintptr
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}
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type hugebytecount interface {
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~uint | ~uint32 | ~uint64 | ~uintptr
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}
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// PageRoundDown returns x rounded down to the nearest multiple of PageSize.
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func PageRoundDown[T bytecount](x T) T {
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return x &^ PageMask
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}
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// PageRoundUp returns x rounded up to the nearest multiple of PageSize. ok is
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// true iff rounding up does not overflow the range of T.
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func PageRoundUp[T bytecount](x T) (val T, ok bool) {
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val = PageRoundDown(x + PageMask)
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ok = val >= x
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return
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}
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// MustPageRoundUp is equivalent to PageRoundUp, but panics if rounding up
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// overflows.
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func MustPageRoundUp[T bytecount](x T) T {
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val, ok := PageRoundUp(x)
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if !ok {
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panic("PageRoundUp overflows")
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}
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return val
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}
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// PageOffset returns the offset of x into its containing page.
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func PageOffset[T bytecount](x T) T {
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return x & PageMask
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}
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// IsPageAligned returns true if x is a multiple of PageSize.
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func IsPageAligned[T bytecount](x T) bool {
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return PageOffset(x) == 0
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}
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// ToPagesRoundUp returns (the number of pages equal to x bytes rounded up,
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// true). If rounding x up to a multiple of PageSize overflows the range of T,
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// ToPagesRoundUp returns (unspecified, false).
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func ToPagesRoundUp[T bytecount](x T) (T, bool) {
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y := x + PageMask
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if y < x {
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return x, false
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}
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return y / PageSize, true
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}
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// HugePageRoundDown returns x rounded down to the nearest multiple of
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// HugePageSize.
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func HugePageRoundDown[T hugebytecount](x T) T {
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return x &^ HugePageMask
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}
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// HugePageRoundUp returns x rounded up to the nearest multiple of
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// HugePageSize. ok is true iff rounding up does not overflow the range of T.
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func HugePageRoundUp[T hugebytecount](x T) (val T, ok bool) {
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val = HugePageRoundDown(x + HugePageMask)
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ok = val >= x
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return
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}
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// MustHugePageRoundUp is equivalent to HugePageRoundUp, but panics if rounding
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// up overflows.
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func MustHugePageRoundUp[T hugebytecount](x T) T {
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val, ok := HugePageRoundUp(x)
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if !ok {
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panic("HugePageRoundUp overflows")
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}
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return val
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}
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// HugePageOffset returns the offset of x into its containing page.
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func HugePageOffset[T hugebytecount](x T) T {
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return x & HugePageMask
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}
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// IsHugePageAligned returns true if x is a multiple of HugePageSize.
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func IsHugePageAligned[T hugebytecount](x T) bool {
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return HugePageOffset(x) == 0
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}
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// CacheLineRoundDown returns the offset rounded down to the nearest multiple
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// of CacheLineSize.
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func CacheLineRoundDown[T bytecount](x T) T {
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return x &^ CacheLineMask
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}
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// CacheLineRoundUp returns the offset rounded up to the nearest multiple of
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// CacheLineSize. ok is true iff rounding up does not overflow the range of T.
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func CacheLineRoundUp[T bytecount](x T) (val T, ok bool) {
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val = CacheLineRoundDown(x + CacheLineMask)
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ok = val >= x
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return
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}
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