fb97f4f354
On machines supporting Riscv SV57 mode like Qemu, Go programs currently crash with the following type of error: runtime: lfstack.push invalid packing: node=0xffffff5908a940 cnt=0x1 packed=0xffff5908a9400001 -> node=0xffff5908a940 The upstream PR fixes this error, but has not yet been merged. Upstream: https://go-review.googlesource.com/c/go/+/409055/4 Signed-off-by: Christian Stewart <christian@paral.in> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
66 lines
2.2 KiB
Diff
66 lines
2.2 KiB
Diff
From 6618c7af436488fa12018cdcd31eeedb3a698745 Mon Sep 17 00:00:00 2001
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From: Dmitry Vyukov <dvyukov@google.com>
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Date: Fri, 27 May 2022 18:55:35 +0200
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Subject: [PATCH] runtime: support riscv64 SV57 mode
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Riscv64 has SV57 mode when user-space VA is 56 bits.
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Linux kernel recently got support for this mode and Go binaries started crashing as:
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runtime: lfstack.push invalid packing: node=0xffffff5908a940 cnt=0x1
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packed=0xffff5908a9400001 -> node=0xffff5908a940
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Adjust lfstack code to use only 8 top bits of pointers on riscv64.
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For context see:
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https://groups.google.com/g/syzkaller-bugs/c/lU0GQTZoNQQ/m/O_c3vmE3AAAJ
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Update #54104
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Change-Id: Ib5d3d6a79c0c6eddf11618d73fcc8bc1832a9c25
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Signed-off-by: Christian Stewart <christian@paral.in>
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---
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Upstream: https://go-review.googlesource.com/c/go/+/409055/4
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---
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src/runtime/lfstack_64bit.go | 12 ++++++++++++
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1 file changed, 12 insertions(+)
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diff --git a/src/runtime/lfstack_64bit.go b/src/runtime/lfstack_64bit.go
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index 154130cf63..39fa647b9e 100644
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--- a/src/runtime/lfstack_64bit.go
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+++ b/src/runtime/lfstack_64bit.go
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@@ -36,12 +36,21 @@ const (
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// We use one bit to distinguish between the two ranges.
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aixAddrBits = 57
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aixCntBits = 64 - aixAddrBits + 3
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+
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+ // Riscv64 SV57 mode gives 56 bits of userspace VA.
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+ // lfstack code supports it, but broader support for SV57 mode is incomplete,
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+ // and there may be other issues (see #54104).
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+ riscv64AddrBits = 56
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+ riscv64CntBits = 64 - riscv64AddrBits + 3
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)
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func lfstackPack(node *lfnode, cnt uintptr) uint64 {
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if GOARCH == "ppc64" && GOOS == "aix" {
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return uint64(uintptr(unsafe.Pointer(node)))<<(64-aixAddrBits) | uint64(cnt&(1<<aixCntBits-1))
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}
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+ if GOARCH == "riscv64" {
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+ return uint64(uintptr(unsafe.Pointer(node)))<<(64-riscv64AddrBits) | uint64(cnt&(1<<riscv64CntBits-1))
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+ }
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return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1))
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}
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@@ -54,5 +63,8 @@ func lfstackUnpack(val uint64) *lfnode {
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if GOARCH == "ppc64" && GOOS == "aix" {
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return (*lfnode)(unsafe.Pointer(uintptr((val >> aixCntBits << 3) | 0xa<<56)))
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}
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+ if GOARCH == "riscv64" {
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+ return (*lfnode)(unsafe.Pointer(uintptr(val >> riscv64CntBits << 3)))
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+ }
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return (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3)))
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}
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--
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2.35.1
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