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 <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
index 12218feb314b8c99aba6e0e2786bdd110f78e16c..8cd9e9f1b424e468228cf5b24a1e9947c8715463 100644 (file)
--- a/src/cmd/link/internal/ld/elf.go
+++ b/src/cmd/link/internal/ld/elf.go
@@ -178,14 +178,7 @@ func Elfinit(ctxt *Link) {
 
        switch ctxt.Arch.Family {
        // 64-bit architectures
-       case sys.PPC64, sys.S390X:
-               if ctxt.Arch.ByteOrder == binary.BigEndian && ctxt.HeadType != objabi.Hopenbsd {
-                       ehdr.Flags = 1 // Version 1 ABI
-               } else {
-                       ehdr.Flags = 2 // Version 2 ABI
-               }
-               fallthrough
-       case sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS64, sys.RISCV64:
+       case sys.AMD64, sys.ARM64, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X:
                if ctxt.Arch.Family == sys.MIPS64 {
                        ehdr.Flags = 0x20000004 // MIPS 3 CPIC
                }
@@ -195,6 +188,12 @@ func Elfinit(ctxt *Link) {
                if ctxt.Arch.Family == sys.RISCV64 {
                        ehdr.Flags = 0x4 // RISCV Float ABI Double
                }
+               if ctxt.Arch.Family == sys.S390X {
+                       ehdr.Flags = 1 // Version 1 ABI
+               }
+               if ctxt.Arch.Family == sys.PPC64 {
+                       ehdr.Flags = 2 // Version 2 ABI
+               }
                elf64 = true
 
                ehdr.Phoff = ELF64HDRSIZE      // Must be ELF64HDRSIZE: first PHdr must follow ELF header

diff --git a/src/runtime/asm_ppc64x.h b/src/runtime/asm_ppc64x.h
index 65870fe020fa3d40a7a8799aae567c79b629d464..8b8149f97b4a8daa922af6d098dd8f13d567bb63 100644 (file)
--- a/src/runtime/asm_ppc64x.h
+++ b/src/runtime/asm_ppc64x.h
@@ -37,19 +37,3 @@
        GLOBL   funcname(SB), NOPTR, $24
 #endif
 #endif
-
-// linux/ppc64 uses ELFv1 which uses function descriptors.
-// These must also look like ABI0 functions on linux/ppc64
-// to work with abi.FuncPCABI0(sigtramp) in os_linux.go.
-// Only static codegen is supported on linux/ppc64, so TOC
-// is not needed.
-#ifdef GOOS_linux
-#ifdef GOARCH_ppc64
-#define GO_PPC64X_HAS_FUNCDESC
-#define DEFINE_PPC64X_FUNCDESC(funcname, localfuncname)        \
-       TEXT    funcname(SB),NOSPLIT|NOFRAME,$0         \
-               DWORD   $localfuncname(SB)              \
-               DWORD   $0                              \
-               DWORD   $0
-#endif
-#endif

diff --git a/src/runtime/rt0_linux_ppc64.s b/src/runtime/rt0_linux_ppc64.s
deleted file mode 100644 (file)
index f527170..0000000
--- a/src/runtime/rt0_linux_ppc64.s
+++ /dev/null
@@ -1,28 +0,0 @@
-// 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 "textflag.h"
-#include "asm_ppc64x.h"
-
-DEFINE_PPC64X_FUNCDESC(_rt0_ppc64_linux, _main<>)
-DEFINE_PPC64X_FUNCDESC(main, _main<>)
-
-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.
-       // There is no TLS base pointer.
-       //
-       // TODO(austin): Support ABI v1 dynamic linking entry point
-       XOR     R0, R0 // Note, newer kernels may not always set R0 to 0.
-       MOVD    $runtime·rt0_go(SB), R12
-       MOVD    R12, CTR
-       MOVBZ   runtime·iscgo(SB), R5
-       CMP     R5, $0
-       BEQ     nocgo
-       BR      (CTR)
-nocgo:
-       MOVD    0(R1), R3 // argc
-       ADD     $8, R1, R4 // argv
-       BR      (CTR)

diff --git a/src/runtime/rt0_linux_ppc64le.s b/src/runtime/rt0_linux_ppc64x.s
similarity index 83%
rename from src/runtime/rt0_linux_ppc64le.s
rename to src/runtime/rt0_linux_ppc64x.s
index 3a6e8863b2da1dcbf5b509d5f1942562426d6930..b1d174dbcd973cdd3f09df9ebbec075c563b932b 100644 (file)
--- a/src/runtime/rt0_linux_ppc64le.s
+++ b/src/runtime/rt0_linux_ppc64x.s
@@ -2,15 +2,25 @@
 // 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"
 
-TEXT _rt0_ppc64le_linux(SB),NOSPLIT,$0
+#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 _rt0_ppc64le_linux_lib(SB),NOSPLIT|NOFRAME,$0
+TEXT ENTRYPOINT_LIB(SB),NOSPLIT|NOFRAME,$0
        JMP _rt0_ppc64x_lib(SB)
 
 TEXT _main<>(SB),NOSPLIT,$-8

diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
index 8735b932ed76d9b27f164913c94cbc435673fb7e..5ecfb0ec625d0964885bbd8b986d05b3af2d95f0 100644 (file)
--- a/src/runtime/sys_linux_ppc64x.s
+++ b/src/runtime/sys_linux_ppc64x.s
@@ -447,13 +447,12 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
        MOVD    24(R1), R2
        RET
 
-#ifdef GO_PPC64X_HAS_FUNCDESC
-DEFINE_PPC64X_FUNCDESC(runtime·sigtramp, sigtramp<>)
+#ifdef GOARCH_ppc64
 // cgo isn't supported on ppc64, but we need to supply a cgoSigTramp function.
-DEFINE_PPC64X_FUNCDESC(runtime·cgoSigtramp, sigtramp<>)
-TEXT sigtramp<>(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
-#else
-// ppc64le doesn't need function descriptors
+TEXT runtime·cgoSigtramp(SB),NOSPLIT|NOFRAME,$0
+       BR      runtime·sigtramp(SB)
+#endif
+
 // Save callee-save registers in the case of signal forwarding.
 // Same as on ARM64 https://golang.org/issue/31827 .
 //
@@ -461,7 +460,6 @@ TEXT sigtramp<>(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
 // a function pointer) as R2 may not be preserved when calling this
 // function. In those cases, the caller preserves their R2.
 TEXT runtime·sigtramp(SB),NOSPLIT|NOFRAME,$0
-#endif
        // This is called with ELF calling conventions. Convert to Go.
        // Allocate space for argument storage to call runtime.sigtrampgo.
        STACK_AND_SAVE_HOST_TO_GO_ABI(32)