From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 82418284662; Tue, 21 Jul 2026 19:47:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784663256; cv=none; b=h3ggfLXqgzClVXoYFtuTVCwgN+UlTZ+CgCZef+NtSrAwf1u5y/e3T47btKBRuX3ZQoEP/b+O292TUvPy3Oi8xGtsDqiQSm06V9NVsrk1E5bS8CgHrkWcU8C5zufrkHea/kAri6hpzWVJDoWDeano2yTSYIcExwVnlvAWrul4fqE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784663256; c=relaxed/simple; bh=ZvD22Yje6F9aYY1ULSm7lCtSL9RsMCvMPs2BlzdcGt8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eRqRLnFvZSK4cNrCyFuvUFItAxTC0f6lNwFuj/YIiDe7j726nTL7g51ffrDW4+M+RWbAc9gbTnWkWZlva6zaSbGhaap+oF+qqet5OJ+s/wsRGkZTxjhdmqWss/V6Xic22hXMfhmsNKAm81U0BWO1uj4yrpAigXpLDdj4Jbu5eRA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bLzYBqZx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bLzYBqZx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EE2B41F000E9; Tue, 21 Jul 2026 19:47:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784663255; bh=65iu+fvv6zg80Z2TEtDP0fDG9xB3qx2rnoHkZO/RyA8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bLzYBqZxvYWoG0KG0AbvgjMGGA+6I2rBc2wyJ09UWl6zhZbAZ8ZJ16MucpdBrOaFE Xe2vVWlSXZo19F8x8i88IlRUDsxuWMltA88Os3xrsCJ7GdwPEAt/a1UyoTyDzBSHjJ K1lnzZCngMXfszWzKR5Yc3cRBGNt4AHuw2DxjtFU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Catalin Marinas , Will Deacon , Ryan Roberts , David Hildenbrand , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Ben Hutchings , Anshuman Khandual , Sasha Levin Subject: [PATCH 6.12 0755/1276] arm64/mm: Optimize TLB flush in unmap_hotplug_[pmd|pud]_range() Date: Tue, 21 Jul 2026 17:19:58 +0200 Message-ID: <20260721152502.972518391@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152446.065700225@linuxfoundation.org> References: <20260721152446.065700225@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Anshuman Khandual [ Upstream commit ff4c5a0de1f2ef7737a8688a86e19301e567020d ] Commit 48478b9f7913 ("arm64/mm: Enable batched TLB flush in unmap_hotplug_range") inadvertently introduced redundant TLB invalidation when clearing a block entry, resulting in unnecessary broadcast invalidation on CPUs without support for range-based invalidation. Re-introduce the old behaviour, along with some expanded comments to help people working in this area next time around. Cc: Catalin Marinas Cc: Will Deacon Cc: Ryan Roberts Cc: David Hildenbrand Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Reported-by: Ben Hutchings Closes: https://lore.kernel.org/all/b0d5836032ce3135bfc473f6bff791306d086925.camel@decadent.org.uk/ Fixes: 48478b9f7913 ("arm64/mm: Enable batched TLB flush in unmap_hotplug_range()") Signed-off-by: Anshuman Khandual Reviewed-by: David Hildenbrand (Arm) Reviewed-by: Catalin Marinas [will: Reword comments and commit message] Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/mm/mmu.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 872227e4fada7f..2b5e0ccc0af555 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -900,7 +900,13 @@ static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, if (free_mapped) { /* CONT blocks are not supported in the vmemmap */ WARN_ON(pmd_cont(pmd)); - flush_tlb_kernel_range(addr, addr + PMD_SIZE); + /* + * Invalidating a block entry requires just + * a single overlapping TLB invalidation, + * so limit the range of the flush to a single + * page. + */ + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); free_hotplug_page_range(pmd_page(pmd), PMD_SIZE, altmap); } @@ -930,7 +936,8 @@ static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, if (pud_sect(pud)) { pud_clear(pudp); if (free_mapped) { - flush_tlb_kernel_range(addr, addr + PUD_SIZE); + /* See comment in unmap_hotplug_pmd_range(). */ + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); free_hotplug_page_range(pud_page(pud), PUD_SIZE, altmap); } -- 2.53.0