From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CA24CC79FA1 for ; Tue, 8 Sep 2026 12:35:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E11256B00A0; Tue, 8 Sep 2026 08:35:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DE8DD6B00A1; Tue, 8 Sep 2026 08:35:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CD80D6B00A2; Tue, 8 Sep 2026 08:35:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id AABD56B00A0 for ; Tue, 8 Sep 2026 08:35:38 -0400 (EDT) Received: from smtpin15.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 5AECE1A066D for ; Tue, 8 Sep 2026 12:35:38 +0000 (UTC) X-FDA: 85190541156.15.95D588A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf02.hostedemail.com (Postfix) with ESMTP id 9C4408000D for ; Tue, 8 Sep 2026 12:35:36 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=K+cwUMT+; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf02.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788870936; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NpWdcIey4xCI1AAiZQP3vw2H/6eRNpO9q4dcacOYsLQ=; b=Xa07hSagHChiV2ojzGFoy4pgn+oI63cwNjuXzXOtFQtahuRhYTx7RVDRr7pvIBpr0DaJFo FMmvJJdenTI5rxuWIjK8BWMYaZLBZV6IGzz2qLr3AR3roNDuMivmh4BSUJjxTuMyeqKs0Y VOJ7y7u6dXyLPmKFido2kYRWdNVDRug= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788870936; b=XnqXSvhCAgitxNmGVdoL5gk/+W0YjU6lPE1EtXw3O3f/45eskeQJ322lq8n2wkYrfZKjiL T6fd4fkmndSygmkl12VszK7oiVbhTU36TlMZcs+uKgZN/BEAeXyGeH4seCy0WOrgOgnOCM Ic2NV77yhS43Vo54avom6rWciZy8foE= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=K+cwUMT+; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf02.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 33EFE601DB; Tue, 8 Sep 2026 12:35:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB33D1F00A3A; Tue, 8 Sep 2026 12:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788870934; bh=NpWdcIey4xCI1AAiZQP3vw2H/6eRNpO9q4dcacOYsLQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=K+cwUMT+d+8/P/ENQVo8DJwc6HGv2hQO+Baa0naUwE3kAv1rdlgVz2F0JO2otmqsR 5iVklIoB7Ri1NDYRWUl76IL47aSyqJrEU+u2MYBj8KejAvZPwT5M0haV6fwHhu61vX hsKmaC5ibrBpStRjPAB/CeZK6AIWwFpISbtm/LTupqa38eQL+EnkABc8GbZqBsS5dN +zWduJuI52AGrGzXleklgVXoZYAZjiHlT8oOhs7SlWXTdgPIATE7ETJoX8t3oe5ICQ cyDq/JnMwFgjyW+BDQ9vDogwSEYfmD3c4PNUaUr1MGiwFNeGB/WSLVO82a3ha+ANYN B9N9mrikFcAtQ== From: "Lorenzo Stoakes (ARM)" Date: Tue, 08 Sep 2026 13:32:17 +0100 Subject: [PATCH v2 08/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for sh-X2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260908-rcu-pagetable-freeing-v2-8-1f60b64e878e@kernel.org> References: <20260908-rcu-pagetable-freeing-v2-0-1f60b64e878e@kernel.org> In-Reply-To: <20260908-rcu-pagetable-freeing-v2-0-1f60b64e878e@kernel.org> To: Andrew Morton , David Hildenbrand , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Guo Ren , Brian Cain , Geert Uytterhoeven , Dinh Nguyen , Simon Schuster , Jonas Bonn , Stefan Kristiansson , Stafford Horne , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Russell King , Vineet Gupta , Michal Simek , Chris Zankel , Max Filippov , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , "David S. Miller" , Andreas Larsson , Richard Henderson , Matt Turner , Magnus Lindholm , Catalin Marinas , Mark Rutland , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Madhavan Srinivasan , Michael Ellerman , "Christophe Leroy (CS GROUP)" , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , John Hubbard , Peter Xu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-openrisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-snps-arc@lists.infradead.org, linux-arch@vger.kernel.org, sparclinux@vger.kernel.org, linux-alpha@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, Hugh Dickins , Qi Zheng , "Lorenzo Stoakes (ARM)" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=4126; i=ljs@kernel.org; h=from:subject:message-id; bh=wpROf24w3fAQ7cNDxi2SGsbF1TZYrv0Ll+LdZO5C4PE=; b=owGbwMvMwCV2fu7ZrsZH9SKMp9WSGLIWMMS4lVQbvv+3RX2Wkqdg2b0oK+mVS0I3JzD2PHdKW pydFzmlo5SFQYyLQVZMkeX5F/H9QSJh8zov+LvBzGFlAhnCwMUpABOxX8nIcFK4ov8A47aDvveq z5q9aj+5p1/U9/UxxmeffPW4BVWU5Rj+B3L/PBGjOLXqWdbBCq85k42q9/08tXTZszu/eG/F/J1 exgYA X-Developer-Key: i=ljs@kernel.org; a=openpgp; fpr=E7F417BF5214569E89D04F46CF9DCD8A81E27F14 X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9C4408000D X-Stat-Signature: 9tb18yythoijei8ntstfupj55jwo1m8m X-HE-Tag: 1788870936-176288 X-HE-Meta: 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 Iad6tbSo yOFMJMkYABEHiwOzaw9vmovzVs8eu8YmAYHlSJgCE+Ii5pc+foljptqFoBgy8QNmyV6q28pXEldCVe/+OMoxkgFzNbkWkV5OkHghRpaV+Cxqv4dzsUPJSMoKNSejtCM+50mlwoW/7BT+zUbuK5FvkF6K4MW4A04itaPzkhsMb01trFb9AngSgzBsAtaYwo2HWvGB/vzikCQoCILNUeUVTMrRoWxKBTaduj1vy4XlEfENPpgRGJgKN46WrBLb09zBBQD4MIrjqbu1Svgar0RTg4dLtlM1Nc+CvLk5q/IBrLnQhk2md0YEh4O+dU89caIxjJOvb9ZBAdow9UUtPKIQ0um3TkoW1jW3Q/J5VJvLxpx6wofnJ9vVKiwimOI7lATOcyPZVpY3yZh5RbQuFAep8O/cYJHoc879KJJ5CPYtL8WUJCnXDXVNjUEuZMOjrP+7IvazsUeNIq8Z8lEbO+kGTt1/MOIBWrkbWCj3qW2Ich5nflIw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Currently, non-x2 sh specifies CONFIG_MMU_GATHER_RCU_TABLE_FREE allowing RCU page table freeing. sh-X2 is problematic because it utilises slab-allocated PMD page tables, and thus tlb_remove_ptdesc() cannot be used in these cases. All other sh variants are fine as commit e3ecf7c7d082 ("mm: pgtable: convert some architectures to use tlb_remove_ptdesc()") already converted page table freeing to use tlb_remove_ptdesc(), which does so after an RCU grace period when CONFIG_MMU_GATHER_RCU_TABLE_FREE is specified. Resolve this issue by firstly specifying CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE for sh-X2, so the arch can provide its own __tlb_remove_table() implementation (called after the RCU grace period). Then, convert __pmd_free_tlb() to tag the pointer to the PMD, and have __tlb_remove_table() check this tag to determine whether to free via the slab or to use pagetable_dtor_free(). This follows the pattern used by sparc64 as implemented in commit 4a0100f7546f ("sparc64: use RCU page table freeing"). Previously __pmd_free_tlb() freed PMD page tables immediately, before any TLB flush IPI. This seems to be a pre-existing bug, which this change also resolves. CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE is only specified for sh-X2, as setting it disables CONFIG_PT_RECLAIM and causes __tlb_remove_table_one() to call tlb_remove_table_sync_rcu() and synchronize_rcu() in turn, and this is not necessary for other sh variants. This forms part of an overall effort to switch every architecture to this mode. Signed-off-by: Lorenzo Stoakes (ARM) --- arch/sh/Kconfig | 3 ++- arch/sh/include/asm/pgalloc.h | 6 +++++- arch/sh/mm/pgtable.c | 20 ++++++++++++++++++++ 3 files changed, 27 insertions(+), 2 deletions(-) diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 204f64912f0e..75236bef6f16 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -33,6 +33,7 @@ config SUPERH select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_KGDB select HAVE_ARCH_SECCOMP_FILTER + select HAVE_ARCH_TLB_REMOVE_TABLE if X2TLB select HAVE_ARCH_TRACEHOOK select HAVE_DEBUG_BUGVERBOSE select HAVE_DEBUG_KMEMLEAK @@ -61,7 +62,7 @@ config SUPERH select HAVE_SYSCALL_TRACEPOINTS select IRQ_FORCED_THREADING select LOCK_MM_AND_FIND_VMA - select MMU_GATHER_RCU_TABLE_FREE if MMU && !X2TLB + select MMU_GATHER_RCU_TABLE_FREE if MMU select MODULES_USE_ELF_RELA select NEED_SG_DMA_LENGTH select NO_DMA if !MMU && !DMA_COHERENT diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h index 6fe7123d38fa..67ce7fa23fa1 100644 --- a/arch/sh/include/asm/pgalloc.h +++ b/arch/sh/include/asm/pgalloc.h @@ -17,7 +17,11 @@ extern void pgd_free(struct mm_struct *mm, pgd_t *pgd); extern void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd); extern pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address); extern void pmd_free(struct mm_struct *mm, pmd_t *pmd); -#define __pmd_free_tlb(tlb, pmdp, addr) pmd_free((tlb)->mm, (pmdp)) +extern void __tlb_remove_table(void *table); + +/* PMDs are slab-allocated, tag so they are freed correctly. */ +#define __pmd_free_tlb(tlb, pmdp, addr) \ + tlb_remove_table((tlb), (void *)((unsigned long)(pmdp) | 1)) #endif static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, diff --git a/arch/sh/mm/pgtable.c b/arch/sh/mm/pgtable.c index 3a4085ea0161..f6184b86b89c 100644 --- a/arch/sh/mm/pgtable.c +++ b/arch/sh/mm/pgtable.c @@ -56,4 +56,24 @@ void pmd_free(struct mm_struct *mm, pmd_t *pmd) { kmem_cache_free(pmd_cachep, pmd); } + +static void __tlb_remove_table_slab(void *table) +{ + kmem_cache_free(pmd_cachep, table); +} + +static void __tlb_remove_table_pgtable(void *table) +{ + pagetable_dtor_free(table); +} + +void __tlb_remove_table(void *table) +{ + const unsigned long addr = (unsigned long)table; + + if (addr & 1) + __tlb_remove_table_slab((void *)(addr & ~1UL)); + else + __tlb_remove_table_pgtable(table); +} #endif /* PAGETABLE_LEVELS > 2 */ -- 2.55.0