From 73df946d56c74384511a194dd01dbe099584fd1a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 15:14:23 +0200 Subject: Adding upstream version 1.16.10. Signed-off-by: Daniel Baumann --- src/runtime/sys_libc.go | 53 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 src/runtime/sys_libc.go (limited to 'src/runtime/sys_libc.go') diff --git a/src/runtime/sys_libc.go b/src/runtime/sys_libc.go new file mode 100644 index 0000000..996c032 --- /dev/null +++ b/src/runtime/sys_libc.go @@ -0,0 +1,53 @@ +// Copyright 2018 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. + +// +build darwin openbsd,amd64 openbsd,arm64 + +package runtime + +import "unsafe" + +// Call fn with arg as its argument. Return what fn returns. +// fn is the raw pc value of the entry point of the desired function. +// Switches to the system stack, if not already there. +// Preserves the calling point as the location where a profiler traceback will begin. +//go:nosplit +func libcCall(fn, arg unsafe.Pointer) int32 { + // Leave caller's PC/SP/G around for traceback. + gp := getg() + var mp *m + if gp != nil { + mp = gp.m + } + if mp != nil && mp.libcallsp == 0 { + mp.libcallg.set(gp) + mp.libcallpc = getcallerpc() + // sp must be the last, because once async cpu profiler finds + // all three values to be non-zero, it will use them + mp.libcallsp = getcallersp() + } else { + // Make sure we don't reset libcallsp. This makes + // libcCall reentrant; We remember the g/pc/sp for the + // first call on an M, until that libcCall instance + // returns. Reentrance only matters for signals, as + // libc never calls back into Go. The tricky case is + // where we call libcX from an M and record g/pc/sp. + // Before that call returns, a signal arrives on the + // same M and the signal handling code calls another + // libc function. We don't want that second libcCall + // from within the handler to be recorded, and we + // don't want that call's completion to zero + // libcallsp. + // We don't need to set libcall* while we're in a sighandler + // (even if we're not currently in libc) because we block all + // signals while we're handling a signal. That includes the + // profile signal, which is the one that uses the libcall* info. + mp = nil + } + res := asmcgocall(fn, arg) + if mp != nil { + mp.libcallsp = 0 + } + return res +} -- cgit v1.2.3