Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 89 insertions, 0 deletions

diff --git a/src/runtime/tagptr_64bit.go b/src/runtime/tagptr_64bit.go
new file mode 100644
index 0000000..9ff11cc
--- /dev/null
+++ b/src/runtime/tagptr_64bit.go
@@ -0,0 +1,89 @@
+// 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.
+
+//go:build amd64 || arm64 || loong64 || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x || wasm
+
+package runtime
+
+import (
+	"internal/goarch"
+	"internal/goos"
+	"unsafe"
+)
+
+const (
+	// addrBits is the number of bits needed to represent a virtual address.
+	//
+	// See heapAddrBits for a table of address space sizes on
+	// various architectures. 48 bits is enough for all
+	// architectures except s390x.
+	//
+	// On AMD64, virtual addresses are 48-bit (or 57-bit) numbers sign extended to 64.
+	// We shift the address left 16 to eliminate the sign extended part and make
+	// room in the bottom for the count.
+	//
+	// On s390x, virtual addresses are 64-bit. There's not much we
+	// can do about this, so we just hope that the kernel doesn't
+	// get to really high addresses and panic if it does.
+	addrBits = 48
+
+	// In addition to the 16 bits taken from the top, we can take 3 from the
+	// bottom, because node must be pointer-aligned, giving a total of 19 bits
+	// of count.
+	tagBits = 64 - addrBits + 3
+
+	// On AIX, 64-bit addresses are split into 36-bit segment number and 28-bit
+	// offset in segment.  Segment numbers in the range 0x0A0000000-0x0AFFFFFFF(LSA)
+	// are available for mmap.
+	// We assume all tagged addresses are from memory allocated with mmap.
+	// We use one bit to distinguish between the two ranges.
+	aixAddrBits = 57
+	aixTagBits  = 64 - aixAddrBits + 3
+
+	// riscv64 SV57 mode gives 56 bits of userspace VA.
+	// tagged pointer code supports it,
+	// but broader support for SV57 mode is incomplete,
+	// and there may be other issues (see #54104).
+	riscv64AddrBits = 56
+	riscv64TagBits  = 64 - riscv64AddrBits + 3
+)
+
+// The number of bits stored in the numeric tag of a taggedPointer
+const taggedPointerBits = (goos.IsAix * aixTagBits) + (goarch.IsRiscv64 * riscv64TagBits) + ((1 - goos.IsAix) * (1 - goarch.IsRiscv64) * tagBits)
+
+// taggedPointerPack created a taggedPointer from a pointer and a tag.
+// Tag bits that don't fit in the result are discarded.
+func taggedPointerPack(ptr unsafe.Pointer, tag uintptr) taggedPointer {
+	if GOOS == "aix" {
+		if GOARCH != "ppc64" {
+			throw("check this code for aix on non-ppc64")
+		}
+		return taggedPointer(uint64(uintptr(ptr))<<(64-aixAddrBits) | uint64(tag&(1<<aixTagBits-1)))
+	}
+	if GOARCH == "riscv64" {
+		return taggedPointer(uint64(uintptr(ptr))<<(64-riscv64AddrBits) | uint64(tag&(1<<riscv64TagBits-1)))
+	}
+	return taggedPointer(uint64(uintptr(ptr))<<(64-addrBits) | uint64(tag&(1<<tagBits-1)))
+}
+
+// Pointer returns the pointer from a taggedPointer.
+func (tp taggedPointer) pointer() unsafe.Pointer {
+	if GOARCH == "amd64" {
+		// amd64 systems can place the stack above the VA hole, so we need to sign extend
+		// val before unpacking.
+		return unsafe.Pointer(uintptr(int64(tp) >> tagBits << 3))
+	}
+	if GOOS == "aix" {
+		return unsafe.Pointer(uintptr((tp >> aixTagBits << 3) | 0xa<<56))
+	}
+	if GOARCH == "riscv64" {
+		return unsafe.Pointer(uintptr(tp >> riscv64TagBits << 3))
+	}
+	return unsafe.Pointer(uintptr(tp >> tagBits << 3))
+}
+
+// Tag returns the tag from a taggedPointer.
+func (tp taggedPointer) tag() uintptr {
+	return uintptr(tp & (1<<taggedPointerBits - 1))
+}