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. 25 TEXT runtimesave_g(SB),NOSPLIT|NOFRAME,$0-0 26 MOVB runtimeiscgo(SB), R31 27 CMP R31, $0 28 BEQ nocgo 29 MOVD runtimetls_g(SB), R31 30 MOVD g, 0(R13)(R31*1) 31 32 nocgo: 33 RET 34 35 // load_g loads the g register from pthread-provided 36 // thread-local memory, for use after calling externally compiled 37 // ppc64 code that overwrote those registers. 38 // 39 // This is never called directly from C code (it doesn't have to 40 // follow the C ABI), but it may be called from a C context, where the 41 // usual Go registers aren't set up. 42 // 43 // NOTE: _cgo_topofstack assumes this only clobbers g (R30), and R31. 44 TEXT runtimeload_g(SB),NOSPLIT|NOFRAME,$0-0 45 MOVD runtimetls_g(SB), R31 46 MOVD 0(R13)(R31*1), g 47 RET 48 49 GLOBL runtimetls_g+0(SB), TLSBSS, $8 50
