| // 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 |
