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 CFBC146C4B9; Tue, 21 Jul 2026 18:22:17 +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=1784658138; cv=none; b=C6bB0nEnCTaqLGKrOkOnEtUYOYuX3UtJL4WCf7A2uobcFu6a6ektj7jUVLQOAZVXBKXTCGk2mdss5VxFrYnXaLb9YfdHRygGUE7UA6IYNZUIExNINOJFgmh2xhDxVScPeC8g08WxtcFsAfUO+Dp7D4KWN2QuisdQAMlTd2isBtM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784658138; c=relaxed/simple; bh=M8S0vQMDb7JBtaW1fS4gxtu/+j0dB8xuu2eF0BkPAYY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lHdeJpM4MI/Fxz0O1rNaTPPD2MM60VraovAeErWHvE2G5btaTEOIoKM8pudkgrmvcfCzMVXol0sHw7i/pNHJLdy3bVqy/PVRb9TVzRfGRPFrYVRYXj2bx5Z+4wpC8nWoAu3mXtqUeLi/JjYAODRoLcS7F4En5EEmMtYZrCnAHTk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NP/PtZ5N; 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="NP/PtZ5N" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4516F1F000E9; Tue, 21 Jul 2026 18:22:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784658137; bh=vhxlZAdk5I92uZuiC0gTM7XxBcCOd76Jdv+wwDD0qsw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NP/PtZ5NXTbTlSz///+O5b23ZQKq5cwlm4wZF7z3eNdoFnhFYZ4oxf5DSIFpJVscJ TcTKEI842OT9pj3ikv9+01RVrxI7HcvcbImbYaYEp5FmK8FWECq9Z05oFVMD5HOXte NKyOszJyOrRYbfWYclm/IpfXknyPhyHB40wCn8sU= 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 6.18 1031/1611] arm64/mm: Optimize TLB flush in unmap_hotplug_[pmd|pud]_range() Date: Tue, 21 Jul 2026 17:19:07 +0200 Message-ID: <20260721152538.589665393@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 ada93622ccf2c0..971cffdb8b48cc 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1515,7 +1515,13 @@ 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); } @@ -1545,7 +1551,8 @@ 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