From 35c5deb1d43b245c19059d1532929ee087e44a84 Mon Sep 17 00:00:00 2001 From: Paul Murphy Date: Wed, 7 Jan 2026 13:48:53 -0600 Subject: all: switch linux-ppc64 target to ELFv2 ABI Go is only capable of producing internally linked, static binaries on linux-ppc64. As such, binaries should run in either ELFv1 or ELFv2 ppc64 userspaces today. This opens the door to enabling cgo and external linking which will require ELFv2 support and userspace, eventually. Fixes #76244 Change-Id: I5ca15037cbe546f352e8693dcf14da51a308b8ca Reviewed-on: https://go-review.googlesource.com/c/go/+/734540 LUCI-TryBot-Result: Go LUCI Reviewed-by: Cherry Mui Reviewed-by: Dmitri Shuralyov --- src/runtime/rt0_linux_ppc64x.s | 64 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 src/runtime/rt0_linux_ppc64x.s (limited to 'src/runtime/rt0_linux_ppc64x.s') diff --git a/src/runtime/rt0_linux_ppc64x.s b/src/runtime/rt0_linux_ppc64x.s new file mode 100644 index 0000000000..b1d174dbcd --- /dev/null +++ b/src/runtime/rt0_linux_ppc64x.s @@ -0,0 +1,64 @@ +// 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) -- cgit v1.3