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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 179ECC433FE for ; Wed, 30 Nov 2022 10:53:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=cLQ/aRjzQoKrRVZxBBnMWYFGoGN5e+EKSdII/71y2DE=; b=pM2TKp5NCQDA7o CCizbRpRqbCTv7fC0zwIdv8GeewJ8C6HpA9dHrtNwFu9VdTMz6HDFpx9gYKjTzfwhxuQOV5jEQXnA t30eK4yOnMdOTimfaFQREl9uSRHSN6P2KQt1UrwwtVtXdnu1pabXwMjPHZ/szjdWUS7jYCj63NgII d6EWmX5ZNZGAs5W78fLFZgrYlziq9MxYseCtGWgk0wu3Rtu6IY5FDRKlVCeS4SLl+n5++iie0O57w lHaMCzxbTRv09hoBkEFXP9v/Mp56S8XvqQAZLhAhKg4VU5Sr7Oy8N8E3cqd4qNn+nlcn1jFMYjwsA zrt025BsZ9BKT7E5q8cw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p0KhG-00FZKG-4h; Wed, 30 Nov 2022 10:52:10 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p0KhC-00FZHW-MY for linux-arm-kernel@lists.infradead.org; Wed, 30 Nov 2022 10:52:08 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A134BB81A9A; Wed, 30 Nov 2022 10:52:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 869EAC433C1; Wed, 30 Nov 2022 10:51:59 +0000 (UTC) Date: Wed, 30 Nov 2022 10:51:56 +0000 From: Catalin Marinas To: Tomislav Novak Cc: Alexei Starovoitov , Will Deacon , "bpf@vger.kernel.org" , "linux-perf-users@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Samuel Gosselin , Mark Rutland , Russell King Subject: Re: [PATCH] hw_breakpoint: fix single-stepping when using bpf_overflow_handler Message-ID: References: <20220923203644.2731604-1-tnovak@fb.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221130_025206_915853_8AE5D889 X-CRM114-Status: GOOD ( 28.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Nov 28, 2022 at 11:59:37AM +0000, Tomislav Novak wrote: > On Tue, Nov 15, 2022 at 03:09:37PM +0000, Catalin Marinas wrote: > > > On ARM platforms is_default_overflow_handler() is used to determine if > > > hw_breakpoint code should single-step over the watchpoint trigger or > > > let the custom handler deal with it. > > > > > > Attaching a BPF program to a watchpoint replaces the handler with > > > bpf_overflow_handler, which isn't recognized as a default handler so we > > > never step over the instruction triggering the data abort exception (the > > > watchpoint keeps firing): > > > > > > # bpftrace -e 'watchpoint:0x10000000:4:w { printf("hit\n"); }' ./wp_test > > > Attaching 1 probe... > > > hit > > > hit > > > hit > > > [...] > > > > > > (wp_test performs a single 4-byte store to address 0x10000000) > > > > > > This patch replaces the check with uses_default_overflow_handler(), which > > > accounts for the bpf_overflow_handler() case by also testing if the handler > > > invokes one of the perf_event_output functions via orig_default_handler. > > > > > > Signed-off-by: Tomislav Novak > > > Tested-by: Samuel Gosselin # arm64 > > > --- > > > arch/arm/kernel/hw_breakpoint.c | 8 ++++---- > > > arch/arm64/kernel/hw_breakpoint.c | 4 ++-- > > > include/linux/perf_event.h | 22 +++++++++++++++++++--- > > > 3 files changed, 25 insertions(+), 9 deletions(-) > > > > It looks like this slipped through the cracks. I'm fine with the patch > > but could you split the arm and arm64 parts in separate patches? Unless > > rmk acks it and we can take the patch through the arm64 (or perf) tree. > > Thanks for reviewing! > > Given the changes in the arch-independent perf_event.h, I think merging it > as a single commit may be easiest (assuming rmk acks it). > > Alternatively I could move arm changes into a separate patch, keeping arm64 > and perf_event.h in this one (possibly splitting out the latter into its own > commit). One that's merged, the arm patch could be submitted to linux-arm. > What would you prefer? Actually, arch/arm*/kernel/hw_breakpoint.c come under the ARM PMU profiling, so no need to split the patch. It may need an ack from the generic perf maintainers for include/linux/perf.h. FWIW, Reviewed-by: Catalin Marinas _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel