| // 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. | |
| //go:build (ppc64 || ppc64le) && linux | |
| #include "go_asm.h" | |
| #include "textflag.h" | |
| #include "asm_ppc64x.h" | |
| #ifdef GOARCH_ppc64 | |
| #define ENTRYPOINT _rt0_ppc64_linux | |
| #define ENTRYPOINT_LIB _rt0_ppc64_linux_lib | |
| #else | |
| #define ENTRYPOINT _rt0_ppc64le_linux | |
| #define ENTRYPOINT_LIB _rt0_ppc64le_linux_lib | |
| #endif | |
| TEXT ENTRYPOINT(SB),NOSPLIT,$0 | |
| XOR R0, R0 // Make sure R0 is zero before _main | |
| BR _main<>(SB) | |
| TEXT ENTRYPOINT_LIB(SB),NOSPLIT|NOFRAME,$0 | |
| JMP _rt0_ppc64x_lib(SB) | |
| TEXT _main<>(SB),NOSPLIT,$-8 | |
| // In a statically linked binary, the stack contains argc, | |
| // argv as argc string pointers followed by a NULL, envv as a | |
| // sequence of string pointers followed by a NULL, and auxv. | |
| // The TLS pointer should be initialized to 0. | |
| // | |
| // In an ELFv2 compliant dynamically linked binary, R3 contains argc, | |
| // R4 contains argv, R5 contains envp, R6 contains auxv, and R13 | |
| // contains the TLS pointer. | |
| // | |
| // When loading via glibc, the first doubleword on the stack points | |
| // to NULL a value. (that is *(uintptr)(R1) == 0). This is used to | |
| // differentiate static vs dynamically linked binaries. | |
| // | |
| // If loading with the musl loader, it doesn't follow the ELFv2 ABI. It | |
| // passes argc/argv similar to the linux kernel, R13 (TLS) is | |
| // initialized, and R3/R4 are undefined. | |
| MOVD (R1), R12 | |
| CMP R12, $0 | |
| BEQ tls_and_argcv_in_reg | |
| // Arguments are passed via the stack (musl loader or a static binary) | |
| MOVD 0(R1), R3 // argc | |
| ADD $8, R1, R4 // argv | |
| // Did the TLS pointer get set? If so, don't change it (e.g musl). | |
| CMP R13, $0 | |
| BNE tls_and_argcv_in_reg | |
| MOVD $runtime·m0+m_tls(SB), R13 // TLS | |
| ADD $0x7000, R13 | |
| tls_and_argcv_in_reg: | |
| BR main(SB) | |
| TEXT main(SB),NOSPLIT,$-8 | |
| MOVD $runtime·rt0_go(SB), R12 | |
| MOVD R12, CTR | |
| BR (CTR) |