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Diffstat (limited to 'tools/checklinkname/known.go')
| -rw-r--r-- | tools/checklinkname/known.go | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/tools/checklinkname/known.go b/tools/checklinkname/known.go new file mode 100644 index 000000000..54e5155fc --- /dev/null +++ b/tools/checklinkname/known.go @@ -0,0 +1,110 @@ +// Copyright 2021 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package checklinkname + +// knownLinknames is the set of the symbols for which we can do a rudimentary +// type-check on. +// +// When analyzing the remote package (e.g., runtime), we verify the symbol +// signature matches 'remote'. When analyzing local packages with //go:linkname +// directives, we verify the symbol signature matches 'local'. +// +// Usually these are identical, but may differ slightly if equivalent +// replacement types are used in the local packages, such as a copy of a struct +// or uintptr instead of a pointer type. +// +// NOTE: It is the responsibility of the developer to verify the safety of the +// signatures used here! This analyzer only checks that types match this map; +// it does not verify compatibility of the entries themselves. +// +// //go:linkname directives with no corresponding entry here will trigger a +// finding. +// +// We preform only rudimentary string-based type-checking due to limitations in +// the analysis framework. Ideally, from the local package we'd lookup the +// remote symbol's types.Object and perform robust type-checking. +// Unfortunately, remote symbols are typically loaded from the remote package's +// gcexportdata. Since //go:linkname targets are usually not exported symbols, +// they are no included in gcexportdata and we cannot load their types.Object. +// +// TODO(b/165820485): Add option to specific per-version signatures. +var knownLinknames = map[string]map[string]linknameSignatures{ + "runtime": map[string]linknameSignatures{ + "entersyscall": linknameSignatures{ + local: "func()", + }, + "entersyscallblock": linknameSignatures{ + local: "func()", + }, + "exitsyscall": linknameSignatures{ + local: "func()", + }, + "fastrand": linknameSignatures{ + local: "func() uint32", + }, + "gopark": linknameSignatures{ + // TODO(b/165820485): add verification of waitReason + // size and reason and traceEv values. + local: "func(unlockf func(uintptr, unsafe.Pointer) bool, lock unsafe.Pointer, reason uint8, traceEv byte, traceskip int)", + remote: "func(unlockf func(*runtime.g, unsafe.Pointer) bool, lock unsafe.Pointer, reason runtime.waitReason, traceEv byte, traceskip int)", + }, + "goready": linknameSignatures{ + local: "func(gp uintptr, traceskip int)", + remote: "func(gp *runtime.g, traceskip int)", + }, + "goyield": linknameSignatures{ + local: "func()", + }, + "memmove": linknameSignatures{ + local: "func(to unsafe.Pointer, from unsafe.Pointer, n uintptr)", + }, + "throw": linknameSignatures{ + local: "func(s string)", + }, + }, + "sync": map[string]linknameSignatures{ + "runtime_canSpin": linknameSignatures{ + local: "func(i int) bool", + }, + "runtime_doSpin": linknameSignatures{ + local: "func()", + }, + "runtime_Semacquire": linknameSignatures{ + // The only difference here is the parameter names. We + // can't just change our local use to match remote, as + // the stdlib runtime and sync packages also disagree + // on the name, and the analyzer checks that use as + // well. + local: "func(addr *uint32)", + remote: "func(s *uint32)", + }, + "runtime_Semrelease": linknameSignatures{ + // See above. + local: "func(addr *uint32, handoff bool, skipframes int)", + remote: "func(s *uint32, handoff bool, skipframes int)", + }, + }, + "syscall": map[string]linknameSignatures{ + "runtime_BeforeFork": linknameSignatures{ + local: "func()", + }, + "runtime_AfterFork": linknameSignatures{ + local: "func()", + }, + "runtime_AfterForkInChild": linknameSignatures{ + local: "func()", + }, + }, +} |