Re: [RFC PATCH 2/2] mm: mmu_notifier fix for tlb_end_vma (build failures)
From: Palmer Dabbelt
Date: Fri Aug 24 2018 - 19:32:17 EST
On Fri, 24 Aug 2018 06:50:48 PDT (-0700), Will Deacon wrote:
On Fri, Aug 24, 2018 at 02:34:27PM +0100, Will Deacon wrote:
On Fri, Aug 24, 2018 at 06:24:19AM -0700, Guenter Roeck wrote:
> On Fri, Aug 24, 2018 at 02:10:27PM +0100, Will Deacon wrote:
> > On Fri, Aug 24, 2018 at 06:07:22AM -0700, Guenter Roeck wrote:
> > > On Thu, Aug 23, 2018 at 06:47:09PM +1000, Nicholas Piggin wrote:
> > > > The generic tlb_end_vma does not call invalidate_range mmu notifier,
> > > > and it resets resets the mmu_gather range, which means the notifier
> > > > won't be called on part of the range in case of an unmap that spans
> > > > multiple vmas.
> > > >
> > > > ARM64 seems to be the only arch I could see that has notifiers and
> > > > uses the generic tlb_end_vma. I have not actually tested it.
> > > >
> > > > Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
> > > > Acked-by: Will Deacon <will.deacon@xxxxxxx>
> > >
> > > This patch breaks riscv builds in mainline.
> >
> > Looks very similar to the breakage we hit on arm64. diff below should fix
> > it.
> >
>
> Unfortunately it doesn't.
>
> In file included from ./arch/riscv/include/asm/pgtable.h:26:0,
> from ./include/linux/memremap.h:7,
> from ./include/linux/mm.h:27,
> from arch/riscv/mm/fault.c:23:
> ./arch/riscv/include/asm/tlb.h: In function âtlb_flushâ:
> ./arch/riscv/include/asm/tlb.h:19:18: error: dereferencing pointer to incomplete type âstruct mmu_gatherâ
> flush_tlb_mm(tlb->mm);
> ^
Sorry, I was a bit quick of the mark there. You'll need a forward
declaration for the paramater type. Here it is with a commit message,
although still untested because I haven't got round to setting up a riscv
toolchain yet.
FWIW, Arnd built them last time he updated the cross tools so you should be
able to get GCC 8.1.0 for RISC-V from there. I use this make.cross script that
I stole from the Intel 0-day robot
https://github.com/palmer-dabbelt/home/blob/master/.local/src/local-scripts/make.cross.bash
If I'm reading it correctly the tools come from here
http://cdn.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/x86_64-gcc-8.1.0-nolibc-riscv64-linux.tar.gz
I use the make.cross script as it makes it super easy to test my
across-the-tree patches on other people's ports.
Will
--->8
From adb9be33d68320edcda80d540a97a647792894d2 Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@xxxxxxx>
Date: Fri, 24 Aug 2018 14:33:48 +0100
Subject: [PATCH] riscv: tlb: Provide definition of tlb_flush() before
including tlb.h
As of commit fd1102f0aade ("mm: mmu_notifier fix for tlb_end_vma"),
asm-generic/tlb.h now calls tlb_flush() from a static inline function,
so we need to make sure that it's declared before #including the
asm-generic header in the arch header.
Since tlb_flush() is a one-liner for riscv, we can define it before
including asm-generic/tlb.h as long as we provide a forward declaration
of struct mmu_gather.
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
---
arch/riscv/include/asm/tlb.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/include/asm/tlb.h b/arch/riscv/include/asm/tlb.h
index c229509288ea..a3d1380ad970 100644
--- a/arch/riscv/include/asm/tlb.h
+++ b/arch/riscv/include/asm/tlb.h
@@ -14,11 +14,13 @@
#ifndef _ASM_RISCV_TLB_H
#define _ASM_RISCV_TLB_H
-#include <asm-generic/tlb.h>
+struct mmu_gather;
static inline void tlb_flush(struct mmu_gather *tlb)
{
flush_tlb_mm(tlb->mm);
Bah, didn't spot the dereference so this won't work either. You basically
just need to copy what I did for arm64 in d475fac95779.
Will