From a41a29ad19c25c3475a65b7265fcad870d954c2a Mon Sep 17 00:00:00 2001 From: Cherry Zhang Date: Mon, 6 Jul 2020 16:03:33 -0400 Subject: [PATCH] runtime: adjust frame pointer on stack copy on ARM64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Frame pointer is enabled on ARM64. When copying stacks, the saved frame pointers need to be adjusted. Updates #39524, #40044. Fixes #58432. Change-Id: I73651fdfd1a6cccae26a5ce02e7e86f6c2fb9bf7 Reviewed-on: https://go-review.googlesource.com/c/go/+/241158 Reviewed-by: Felix Geisendörfer Run-TryBot: Cherry Mui Reviewed-by: Michael Knyszek TryBot-Result: Gopher Robot --- src/runtime/stack.go | 26 +++++++++-- src/runtime/stack_test.go | 12 +++++ src/runtime/testdata/testprog/framepointer.go | 44 +++++++++++++++++++ .../testdata/testprog/framepointer_amd64.s | 9 ++++ .../testdata/testprog/framepointer_arm64.s | 9 ++++ 5 files changed, 96 insertions(+), 4 deletions(-) create mode 100644 src/runtime/testdata/testprog/framepointer.go create mode 100644 src/runtime/testdata/testprog/framepointer_amd64.s create mode 100644 src/runtime/testdata/testprog/framepointer_arm64.s diff --git a/src/runtime/stack.go b/src/runtime/stack.go index 14e1a75ccd2454..e1e6c7e82a45fe 100644 --- a/src/runtime/stack.go +++ b/src/runtime/stack.go @@ -537,7 +537,7 @@ var ptrnames = []string{ // +------------------+ <- frame->argp // | return address | // +------------------+ -// | caller's BP (*) | (*) if framepointer_enabled && varp < sp +// | caller's BP (*) | (*) if framepointer_enabled && varp > sp // +------------------+ <- frame->varp // | locals | // +------------------+ @@ -549,6 +549,8 @@ var ptrnames = []string{ // | args from caller | // +------------------+ <- frame->argp // | caller's retaddr | +// +------------------+ +// | caller's FP (*) | (*) on ARM64, if framepointer_enabled && varp > sp // +------------------+ <- frame->varp // | locals | // +------------------+ @@ -556,6 +558,9 @@ var ptrnames = []string{ // +------------------+ // | return address | // +------------------+ <- frame->sp +// +// varp > sp means that the function has a frame; +// varp == sp means frameless function. type adjustinfo struct { old stack @@ -673,9 +678,8 @@ func adjustframe(frame *stkframe, adjinfo *adjustinfo) { adjustpointers(unsafe.Pointer(frame.varp-size), &locals, adjinfo, f) } - // Adjust saved base pointer if there is one. - // TODO what about arm64 frame pointer adjustment? - if goarch.ArchFamily == goarch.AMD64 && frame.argp-frame.varp == 2*goarch.PtrSize { + // Adjust saved frame pointer if there is one. + if (goarch.ArchFamily == goarch.AMD64 || goarch.ArchFamily == goarch.ARM64) && frame.argp-frame.varp == 2*goarch.PtrSize { if stackDebug >= 3 { print(" saved bp\n") } @@ -689,6 +693,10 @@ func adjustframe(frame *stkframe, adjinfo *adjustinfo) { throw("bad frame pointer") } } + // On AMD64, this is the caller's frame pointer saved in the current + // frame. + // On ARM64, this is the frame pointer of the caller's caller saved + // by the caller in its frame (one word below its SP). adjustpointer(adjinfo, unsafe.Pointer(frame.varp)) } @@ -750,7 +758,17 @@ func adjustctxt(gp *g, adjinfo *adjustinfo) { throw("bad top frame pointer") } } + oldfp := gp.sched.bp adjustpointer(adjinfo, unsafe.Pointer(&gp.sched.bp)) + if GOARCH == "arm64" { + // On ARM64, the frame pointer is saved one word *below* the SP, + // which is not copied or adjusted in any frame. Do it explicitly + // here. + if oldfp == gp.sched.sp-goarch.PtrSize { + memmove(unsafe.Pointer(gp.sched.bp), unsafe.Pointer(oldfp), goarch.PtrSize) + adjustpointer(adjinfo, unsafe.Pointer(gp.sched.bp)) + } + } } func adjustdefers(gp *g, adjinfo *adjustinfo) { diff --git a/src/runtime/stack_test.go b/src/runtime/stack_test.go index 9a096f553896b8..4e3f369f2f0dd5 100644 --- a/src/runtime/stack_test.go +++ b/src/runtime/stack_test.go @@ -927,3 +927,15 @@ func deferHeapAndStack(n int) (r int) { // Pass a value to escapeMe to force it to escape. var escapeMe = func(x any) {} + +func TestFramePointerAdjust(t *testing.T) { + switch GOARCH { + case "amd64", "arm64": + default: + t.Skipf("frame pointer is not supported on %s", GOARCH) + } + output := runTestProg(t, "testprog", "FramePointerAdjust") + if output != "" { + t.Errorf("output:\n%s\n\nwant no output", output) + } +} diff --git a/src/runtime/testdata/testprog/framepointer.go b/src/runtime/testdata/testprog/framepointer.go new file mode 100644 index 00000000000000..cee6f7da291000 --- /dev/null +++ b/src/runtime/testdata/testprog/framepointer.go @@ -0,0 +1,44 @@ +// Copyright 2023 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 amd64 || arm64 + +package main + +import "unsafe" + +func init() { + register("FramePointerAdjust", FramePointerAdjust) +} + +func FramePointerAdjust() { framePointerAdjust1(0) } + +//go:noinline +func framePointerAdjust1(x int) { + argp := uintptr(unsafe.Pointer(&x)) + fp := *getFP() + if !(argp-0x100 <= fp && fp <= argp+0x100) { + print("saved FP=", fp, " &x=", argp, "\n") + panic("FAIL") + } + + // grow the stack + grow(10000) + + // check again + argp = uintptr(unsafe.Pointer(&x)) + fp = *getFP() + if !(argp-0x100 <= fp && fp <= argp+0x100) { + print("saved FP=", fp, " &x=", argp, "\n") + panic("FAIL") + } +} + +func grow(n int) { + if n > 0 { + grow(n - 1) + } +} + +func getFP() *uintptr diff --git a/src/runtime/testdata/testprog/framepointer_amd64.s b/src/runtime/testdata/testprog/framepointer_amd64.s new file mode 100644 index 00000000000000..2cd12991d6d772 --- /dev/null +++ b/src/runtime/testdata/testprog/framepointer_amd64.s @@ -0,0 +1,9 @@ +// Copyright 2023 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" + +TEXT ·getFP(SB), NOSPLIT|NOFRAME, $0-8 + MOVQ BP, ret+0(FP) + RET diff --git a/src/runtime/testdata/testprog/framepointer_arm64.s b/src/runtime/testdata/testprog/framepointer_arm64.s new file mode 100644 index 00000000000000..cbaa28604372a7 --- /dev/null +++ b/src/runtime/testdata/testprog/framepointer_arm64.s @@ -0,0 +1,9 @@ +// Copyright 2023 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" + +TEXT ·getFP(SB), NOSPLIT|NOFRAME, $0-8 + MOVD R29, ret+0(FP) + RET