diff mbox series

libgo patch committed: Fix lfstack for AIX

Message ID CAOyqgcWEWUTUnMV-fe=UZU_wa+FuOBYh8WoVoqR=xxhAxV4saA@mail.gmail.com
State New
Headers show
Series libgo patch committed: Fix lfstack for AIX | expand

Commit Message

Ian Lance Taylor Aug. 29, 2017, 6:59 p.m. UTC 
This patch by Tony Reix fixes the runtime package's lock-free stack
code to work on 64-bit AIX.  Bootstrapped on x86_64-pc-linux-gnu.
Committed to mainline.

Ian
diff mbox series

Patch

Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE	(revision 251188)
+++ gcc/go/gofrontend/MERGE	(working copy)
@@ -1,4 +1,4 @@ 
-2c4a2bd826e58c8c8c51b9196c8d2c67abc4037e
+db8e3801bf8508656606d6e465c76cdc6e9a9eb7
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
Index: libgo/go/runtime/lfstack_64bit.go
===================================================================
--- libgo/go/runtime/lfstack_64bit.go	(revision 250873)
+++ libgo/go/runtime/lfstack_64bit.go	(working copy)
@@ -43,6 +43,14 @@  const (
 	// 52 address bits each (with 64k page size).
 	ia64AddrBits = 55
 	ia64CntBits  = 64 - ia64AddrBits + 3
+
+	// On AIX, 64-bit addresses are split into 36-bit segment number and 28-bit
+	// offset in segment.  Segment numbers in the range 0x070000000-0x07FFFFFFF
+	// and 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
 )
 
 func lfstackPack(node *lfnode, cnt uintptr) uint64 {
@@ -54,6 +62,9 @@  func lfstackPack(node *lfnode, cnt uintp
 		val := uint64(uintptr(unsafe.Pointer(node)))
 		return (val<<(64-ia64AddrBits))&(1<<(64-3)-1) | val&^(1<<(64-3)-1) | uint64(cnt&(1<<ia64CntBits-1))
 	}
+	if GOARCH == "ppc64" && GOOS == "aix" {
+		return uint64(uintptr(unsafe.Pointer(node)))<<(64-aixAddrBits) | uint64(cnt&(1<<aixCntBits-1))
+	}
 	return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1))
 }
 
@@ -69,5 +80,12 @@  func lfstackUnpack(val uint64) *lfnode {
 	if GOARCH == "ia64" {
 		return (*lfnode)(unsafe.Pointer(uintptr((val>>ia64CntBits<<3)&(1<<(64-3)-1) | val&^(1<<(64-3)-1))))
 	}
+	if GOARCH == "ppc64" && GOOS == "aix" {
+		if val&(1<<63) != 0 {
+			return (*lfnode)(unsafe.Pointer(uintptr((val >> aixCntBits << 3) | 0x7<<56)))
+		} else {
+			return (*lfnode)(unsafe.Pointer(uintptr((val >> aixCntBits << 3) | 0xa<<56)))
+		}
+	}
 	return (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3)))
 }