Editando: tls_ppc64x.s
// Copyright 2014 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. //go:build ppc64 || ppc64le #include "go_asm.h" #include "go_tls.h" #include "funcdata.h" #include "textflag.h" // We have to resort to TLS variable to save g (R30). // One reason is that external code might trigger // SIGSEGV, and our runtime.sigtramp don't even know we // are in external code, and will continue to use R30, // this might well result in another SIGSEGV. // save_g saves the g register into pthread-provided // thread-local memory, so that we can call externally compiled // ppc64 code that will overwrite this register. // // If !iscgo, this is a no-op. // // NOTE: setg_gcc<> assume this clobbers only R31. TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0 #ifndef GOOS_aix #ifndef GOOS_openbsd MOVBZ runtime·iscgo(SB), R31 CMP R31, $0 BEQ nocgo #endif #endif MOVD runtime·tls_g(SB), R31 MOVD g, 0(R31) nocgo: RET // load_g loads the g register from pthread-provided // thread-local memory, for use after calling externally compiled // ppc64 code that overwrote those registers. // // This is never called directly from C code (it doesn't have to // follow the C ABI), but it may be called from a C context, where the // usual Go registers aren't set up. // // NOTE: _cgo_topofstack assumes this only clobbers g (R30), and R31. TEXT runtime·load_g(SB),NOSPLIT|NOFRAME,$0-0 MOVD runtime·tls_g(SB), R31 MOVD 0(R31), g RET GLOBL runtime·tls_g+0(SB), TLSBSS+DUPOK, $8
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