diff options
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/lfstack.go | 4 | ||||
| -rw-r--r-- | src/runtime/lfstack_linux_power64x.go | 20 |
2 files changed, 17 insertions, 7 deletions
diff --git a/src/runtime/lfstack.go b/src/runtime/lfstack.go index 4a20fff9d8..8a36a67b35 100644 --- a/src/runtime/lfstack.go +++ b/src/runtime/lfstack.go @@ -12,6 +12,10 @@ import "unsafe" func lfstackpush(head *uint64, node *lfnode) { node.pushcnt++ new := lfstackPack(node, node.pushcnt) + if node1, _ := lfstackUnpack(new); node1 != node { + println("runtime: lfstackpush invalid packing: node=", node, " cnt=", hex(node.pushcnt), " packed=", hex(new), " -> node=", node1, "\n") + gothrow("lfstackpush") + } for { old := atomicload64(head) node.next, _ = lfstackUnpack(old) diff --git a/src/runtime/lfstack_linux_power64x.go b/src/runtime/lfstack_linux_power64x.go index 7a122bf92c..89e389fc72 100644 --- a/src/runtime/lfstack_linux_power64x.go +++ b/src/runtime/lfstack_linux_power64x.go @@ -9,18 +9,24 @@ package runtime import "unsafe" -// On Power64, Linux limits the user address space to 43 bits. -// (https://www.kernel.org/doc/ols/2001/ppc64.pdf) -// In addition to the 21 bits taken from the top, we can take 3 from the -// bottom, because node must be pointer-aligned, giving a total of 24 bits +// On Power64, Linux limits the user address space to 46 bits (see +// TASK_SIZE_USER64 in the Linux kernel). This has grown over time, +// so here we allow 48 bit addresses. +// +// 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. +const ( + addrBits = 48 + cntBits = 64 - addrBits + 3 +) func lfstackPack(node *lfnode, cnt uintptr) uint64 { - return uint64(uintptr(unsafe.Pointer(node)))<<21 | uint64(cnt&(1<<24-1)) + return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1)) } func lfstackUnpack(val uint64) (node *lfnode, cnt uintptr) { - node = (*lfnode)(unsafe.Pointer(uintptr(val >> 24 << 3))) - cnt = uintptr(val & (1<<24 - 1)) + node = (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3))) + cnt = uintptr(val & (1<<cntBits - 1)) return } |