1// Copyright 2014 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// +build ppc64 ppc64le 6 7#include "go_asm.h" 8#include "go_tls.h" 9#include "funcdata.h" 10#include "textflag.h" 11 12// We have to resort to TLS variable to save g (R30). 13// One reason is that external code might trigger 14// SIGSEGV, and our runtime.sigtramp don't even know we 15// are in external code, and will continue to use R30, 16// this might well result in another SIGSEGV. 17 18// save_g saves the g register into pthread-provided 19// thread-local memory, so that we can call externally compiled 20// ppc64 code that will overwrite this register. 21// 22// If !iscgo, this is a no-op. 23// 24// NOTE: setg_gcc<> assume this clobbers only R31. 25TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0 26#ifndef GOOS_aix 27 MOVBZ runtime·iscgo(SB), R31 28 CMP R31, $0 29 BEQ nocgo 30#endif 31 MOVD runtime·tls_g(SB), R31 32 MOVD g, 0(R13)(R31*1) 33 34nocgo: 35 RET 36 37// load_g loads the g register from pthread-provided 38// thread-local memory, for use after calling externally compiled 39// ppc64 code that overwrote those registers. 40// 41// This is never called directly from C code (it doesn't have to 42// follow the C ABI), but it may be called from a C context, where the 43// usual Go registers aren't set up. 44// 45// NOTE: _cgo_topofstack assumes this only clobbers g (R30), and R31. 46TEXT runtime·load_g(SB),NOSPLIT|NOFRAME,$0-0 47 MOVD runtime·tls_g(SB), R31 48 MOVD 0(R13)(R31*1), g 49 RET 50 51GLOBL runtime·tls_g+0(SB), TLSBSS+DUPOK, $8 52