From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.101.70]:57614 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726960AbeHXRZl (ORCPT ); Fri, 24 Aug 2018 13:25:41 -0400 Date: Fri, 24 Aug 2018 14:50:48 +0100 From: Will Deacon Subject: Re: [RFC PATCH 2/2] mm: mmu_notifier fix for tlb_end_vma (build failures) Message-ID: <20180824135048.GF11868@brain-police> References: <20180823084709.19717-1-npiggin@gmail.com> <20180823084709.19717-3-npiggin@gmail.com> <20180824130722.GA31409@roeck-us.net> <20180824131026.GB11868@brain-police> <20180824132419.GA9983@roeck-us.net> <20180824133427.GC11868@brain-police> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180824133427.GC11868@brain-police> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Guenter Roeck Cc: Nicholas Piggin , Peter Zijlstra , torvalds@linux-foundation.org, luto@kernel.org, x86@kernel.org, bp@alien8.de, riel@surriel.com, jannh@google.com, ascannell@google.com, dave.hansen@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Miller , Martin Schwidefsky , Michael Ellerman , linux-arch@vger.kernel.org, Palmer Dabbelt , linux-riscv@lists.infradead.org Message-ID: <20180824135048.TFlIfZnxEvZrHZLfSQIbGYDdOZ4X94AeJF6qKxj3gCA@z> 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 > > > > > Acked-by: Will Deacon > > > > > > > > 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 ‘tlb_flush’: > > ./arch/riscv/include/asm/tlb.h:19:18: error: dereferencing pointer to incomplete type ‘struct mmu_gather’ > > 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. > > Will > > --->8 > > From adb9be33d68320edcda80d540a97a647792894d2 Mon Sep 17 00:00:00 2001 > From: Will Deacon > 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 > Signed-off-by: Will Deacon > --- > 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 > +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