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G struct offset is a pointer to an offset since go1.20 (#3196)

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Quim Muntal 2022-11-16 18:44:27 +01:00 committed by GitHub
parent d15c86e0cf
commit f439987f14
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1 changed files with 35 additions and 20 deletions
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55
pkg/proc/bininfo.go
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@ -94,7 +94,8 @@ type BinaryInfo struct {
types map[string]dwarfRef
packageVars []packageVar // packageVars is a list of all global/package variables in debug_info, sorted by address
gStructOffset uint64
gStructOffset uint64
gStructOffsetIsPtr bool
// consts[off] lists all the constants with the type defined at offset off.
consts constantsMap
@ -700,7 +701,7 @@ func loadBinaryInfo(bi *BinaryInfo, image *Image, path string, entryPoint uint64
// struct in thread local storage.
func (bi *BinaryInfo) GStructOffset(mem MemoryReadWriter) (uint64, error) {
offset := bi.gStructOffset
if bi.GOOS == "windows" && bi.Arch.Name == "arm64" {
if bi.gStructOffsetIsPtr {
// The G struct offset from the TLS section is a pointer
// and the address must be dereferenced to find to actual G struct offset.
var err error
@ -1645,38 +1646,52 @@ func loadBinaryInfoPE(bi *BinaryInfo, image *Image, path string, entryPoint uint
wg.Add(2)
go bi.parseDebugFramePE(image, peFile, debugInfoBytes, wg)
go bi.loadDebugInfoMaps(image, debugInfoBytes, debugLineBytes, wg, nil)
if image.index == 0 {
// determine g struct offset only when loading the executable file
wg.Add(1)
go bi.setGStructOffsetPE(entryPoint, peFile, wg)
}
go bi.loadDebugInfoMaps(image, debugInfoBytes, debugLineBytes, wg, func() {
// setGStructOffsetPE requires the image compile units to be loaded,
// so it can't be called concurrently with loadDebugInfoMaps.
if image.index == 0 {
// determine g struct offset only when loading the executable file.
bi.setGStructOffsetPE(entryPoint, peFile)
}
})
return nil
}
func (bi *BinaryInfo) setGStructOffsetPE(entryPoint uint64, peFile *pe.File, wg *sync.WaitGroup) {
defer wg.Done()
switch _PEMachine(peFile.Machine) {
case _IMAGE_FILE_MACHINE_AMD64:
// Use ArbitraryUserPointer (0x28) as pointer to pointer
// to G struct per:
// https://golang.org/src/runtime/cgo/gcc_windows_amd64.c
bi.gStructOffset = 0x28
case _IMAGE_FILE_MACHINE_ARM64:
// Use runtime.tls_g as pointer to offset from R18 to G struct:
// https://golang.org/src/runtime/sys_windows_arm64.s:runtime·wintls
func (bi *BinaryInfo) setGStructOffsetPE(entryPoint uint64, peFile *pe.File) {
readtls_g := func() uint64 {
for _, s := range peFile.Symbols {
if s.Name == "runtime.tls_g" {
i := int(s.SectionNumber) - 1
if 0 <= i && i < len(peFile.Sections) {
sect := peFile.Sections[i]
if s.Value < sect.VirtualSize {
bi.gStructOffset = entryPoint + uint64(sect.VirtualAddress) + uint64(s.Value)
return entryPoint + uint64(sect.VirtualAddress) + uint64(s.Value)
}
}
break
}
}
return 0
}
switch _PEMachine(peFile.Machine) {
case _IMAGE_FILE_MACHINE_AMD64:
producer := bi.Producer()
if producer != "" && goversion.ProducerAfterOrEqual(producer, 1, 20) {
// Use runtime.tls_g as pointer to offset from GS to G struct:
// https://golang.org/src/runtime/sys_windows_amd64.s
bi.gStructOffset = readtls_g()
bi.gStructOffsetIsPtr = true
} else {
// Use ArbitraryUserPointer (0x28) as pointer to pointer
// to G struct per:
// https://golang.org/src/runtime/cgo/gcc_windows_amd64.c
bi.gStructOffset = 0x28
}
case _IMAGE_FILE_MACHINE_ARM64:
// Use runtime.tls_g as pointer to offset from R18 to G struct:
// https://golang.org/src/runtime/sys_windows_arm64.s
bi.gStructOffset = readtls_g()
bi.gStructOffsetIsPtr = true
}
}