diff options
Diffstat (limited to 'src/runtime/tls_s390x.s')
| -rw-r--r-- | src/runtime/tls_s390x.s | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/src/runtime/tls_s390x.s b/src/runtime/tls_s390x.s new file mode 100644 index 0000000..cb6a21c --- /dev/null +++ b/src/runtime/tls_s390x.s @@ -0,0 +1,51 @@ +// Copyright 2016 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. + +#include "go_asm.h" +#include "go_tls.h" +#include "funcdata.h" +#include "textflag.h" + +// We have to resort to TLS variable to save g (R13). +// 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 R13, +// 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 +// s390x code that will overwrite this register. +// +// If !iscgo, this is a no-op. +// +// NOTE: setg_gcc<> assume this clobbers only R10 and R11. +TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0 + MOVB runtime·iscgo(SB), R10 + CMPBEQ R10, $0, nocgo + MOVW AR0, R11 + SLD $32, R11 + MOVW AR1, R11 + MOVD runtime·tls_g(SB), R10 + MOVD g, 0(R10)(R11*1) +nocgo: + RET + +// load_g loads the g register from pthread-provided +// thread-local memory, for use after calling externally compiled +// s390x 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 (R13), R10 and R11. +TEXT runtime·load_g(SB),NOSPLIT|NOFRAME,$0-0 + MOVW AR0, R11 + SLD $32, R11 + MOVW AR1, R11 + MOVD runtime·tls_g(SB), R10 + MOVD 0(R10)(R11*1), g + RET + +GLOBL runtime·tls_g+0(SB),TLSBSS,$8 |