From 43a123c1ae6613b3efeed291fa552ecd909d3acf Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Tue, 16 Apr 2024 21:23:18 +0200
Subject: Adding upstream version 1.20.14.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/runtime/lfstack_64bit.go | 70 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/runtime/lfstack_64bit.go

(limited to 'src/runtime/lfstack_64bit.go')

diff --git a/src/runtime/lfstack_64bit.go b/src/runtime/lfstack_64bit.go
new file mode 100644
index 0000000..88cbd3b
--- /dev/null
+++ b/src/runtime/lfstack_64bit.go
@@ -0,0 +1,70 @@
+// 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 "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.
+	cntBits = 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 lfnode addresses are from memory allocated with mmap.
+	// We use one bit to distinguish between the two ranges.
+	aixAddrBits = 57
+	aixCntBits  = 64 - aixAddrBits + 3
+
+	// riscv64 SV57 mode gives 56 bits of userspace VA.
+	// lfstack code supports it, but broader support for SV57 mode is incomplete,
+	// and there may be other issues (see #54104).
+	riscv64AddrBits = 56
+	riscv64CntBits  = 64 - riscv64AddrBits + 3
+)
+
+func lfstackPack(node *lfnode, cnt uintptr) uint64 {
+	if GOARCH == "ppc64" && GOOS == "aix" {
+		return uint64(uintptr(unsafe.Pointer(node)))<<(64-aixAddrBits) | uint64(cnt&(1<<aixCntBits-1))
+	}
+	if GOARCH == "riscv64" {
+		return uint64(uintptr(unsafe.Pointer(node)))<<(64-riscv64AddrBits) | uint64(cnt&(1<<riscv64CntBits-1))
+	}
+	return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1))
+}
+
+func lfstackUnpack(val uint64) *lfnode {
+	if GOARCH == "amd64" {
+		// amd64 systems can place the stack above the VA hole, so we need to sign extend
+		// val before unpacking.
+		return (*lfnode)(unsafe.Pointer(uintptr(int64(val) >> cntBits << 3)))
+	}
+	if GOARCH == "ppc64" && GOOS == "aix" {
+		return (*lfnode)(unsafe.Pointer(uintptr((val >> aixCntBits << 3) | 0xa<<56)))
+	}
+	if GOARCH == "riscv64" {
+		return (*lfnode)(unsafe.Pointer(uintptr(val >> riscv64CntBits << 3)))
+	}
+	return (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3)))
+}
-- 
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