From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7814A763FD; Sun, 24 Mar 2024 22:47:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711320451; cv=none; b=gdgDNEjQq3HNRAm8Q5lXCMFs+NeXoftRa818Q0ly7rLCBAQCTegu28RaNetJWSsSjb3jb3V1rMTgNQWZqLKplo0U80hQi8iS/aHvm78TJOWHK/v6NZm6o+WZpmgFFBUrGlgYvMyQbC/vuu92sVKr2+whTyy7rLzcATdx9ZiIpzY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711320451; c=relaxed/simple; bh=5F7XSSCngd7SJiSXtRGZSco15qRwSXu6/QNItN9LrzE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tpmUyGLCt2fWu7oa0FtAEw+svn02jj2SXRLYQK2ygH5VRE/bgAmifZjXUtT310i0fQZWjplHfsvTKlPaDIePySPGqZ9nSd0HryVnqxKseX/xlOG3XQQV2KxSAceI4aS4XU7Y/th2AHkZw1LFdnZtSXpQyxenx7iKvH8SJcCIjAo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pF8umtIt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pF8umtIt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5393EC43394; Sun, 24 Mar 2024 22:47:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711320451; bh=5F7XSSCngd7SJiSXtRGZSco15qRwSXu6/QNItN9LrzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pF8umtItCrqEpHtsmJOL4IwiZZ+XEheSECokCt8nPvWD3ur1fs++twbvex+Mlf7D0 T7lPEpO/iDpvDmVb2GcOa0KSGEKKCLYk3VHxTXMEDizissrCbjZvpwpddG7WTz2TCj RFy/5+/MTQw+84xQKAiEtkrpB4/hKiYIT7sKtyBqtmj1K1nYo5LIoMnaGFoH7widhu nvCNDQ9soXH/TOjIJyiV6i7HxEe4PesKeMvVx8tA2qK/rH51QU7MOmCiZsV2+77fY9 RdZrmWl2gzDLhd3LJ9yd/38vvfk3/hReF5tKqXEPf5Hx1hkGl/AILfZyxVCp8GH35m MCWg7DHdfM2AA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ilkka Koskinen , Robin Murphy , Will Deacon , Sasha Levin Subject: [PATCH 6.7 009/713] perf/arm-cmn: Workaround AmpereOneX errata AC04_MESH_1 (incorrect child count) Date: Sun, 24 Mar 2024 18:35:35 -0400 Message-ID: <20240324224720.1345309-10-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324224720.1345309-1-sashal@kernel.org> References: <20240324224720.1345309-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Ilkka Koskinen [ Upstream commit 50572064ec7109b00eef8880e905f55861c8b3de ] AmpereOneX mesh implementation has a bug in HN-P nodes that makes them report incorrect child count. The failing crosspoints report 8 children while they only have two. When the driver tries to access the inexistent child nodes, it believes it has reached an invalid node type and probing fails. The workaround is to ignore those incorrect child nodes and continue normally. Signed-off-by: Ilkka Koskinen [ rm: rewrote simpler generalised version ] Tested-by: Ilkka Koskinen Signed-off-by: Robin Murphy Link: https://lore.kernel.org/r/ce4b1442135fe03d0de41859b04b268c88c854a3.1707498577.git.robin.murphy@arm.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/perf/arm-cmn.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index c584165b13bab..7e3aa7e2345fa 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -2305,6 +2305,17 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset) dev_dbg(cmn->dev, "ignoring external node %llx\n", reg); continue; } + /* + * AmpereOneX erratum AC04_MESH_1 makes some XPs report a bogus + * child count larger than the number of valid child pointers. + * A child offset of 0 can only occur on CMN-600; otherwise it + * would imply the root node being its own grandchild, which + * we can safely dismiss in general. + */ + if (reg == 0 && cmn->part != PART_CMN600) { + dev_dbg(cmn->dev, "bogus child pointer?\n"); + continue; + } arm_cmn_init_node_info(cmn, reg & CMN_CHILD_NODE_ADDR, dn); -- 2.43.0