From patchwork Tue May 7 14:13:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13657165 X-Patchwork-Delegate: bpf@iogearbox.net 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 2EB8F161322; Tue, 7 May 2024 14:13:48 +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=1715091228; cv=none; b=ePdO//oAoOGBUzP/DRTAa94vNfAMx1PavL3qzN5//w9zBPw5/igrMaBmUVndLld5AuowiItoLCrDs5IGwmp31BpT7YP9gL6VHBdi81ySbD6xTCg4vd1T03fFvq8NmiRuwJRJAl4KRA1ALi/Qi1KvCQXflRCPZLuFyjYAFxDWSkU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715091228; c=relaxed/simple; bh=f5W7Es8Asv6qhDQvPibvV7iDgsG1y7b4XsCF+sg5Yg0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=s+RxYcIcZb1NiiCLM+fnZpDxoeBLexdNhgdrx6NRhJ5QDYRq7jONtywaGIb9YvJq5EKxw1BkTmhqpBgFFpdaMmqRVSp3YviCjkb+y2mTnoenC8rx1dNMkXEGwZne0PidrqKo+uxrhrEBwXX1OQPN0ndGzyrzbK7sDxGegmZ4Lpw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AOpgaYzg; 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="AOpgaYzg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D28E8C2BBFC; Tue, 7 May 2024 14:13:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715091227; bh=f5W7Es8Asv6qhDQvPibvV7iDgsG1y7b4XsCF+sg5Yg0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AOpgaYzg3igdK/6Aw2Z0aa5JUYyN4E/5aGrhQ3IrFvKWqoOR+TDPamXcN1AmV1oWt pD/RppUBGbN4dFeFH+EGneLi1R+65T7rwgwxifArOeST4JST3yE+/wEm9I8b07GvLg U70EyCesZ31zWWXa3A3kcab8ErYSDfJ+8dBATSWyQmpnmYM9h89dvBSH5yLQQNPkf/ Jxyqniiea+pTf4FZHvCt4XsYhWdrt1x1MXlhKJX+PeAfu2GecIBH62PP7ea2lNXjek t5AgC+AJTsaVp6BpPQZPGqD2CUfUfPRrK37kTAOGauj1W9KkH0H54jGEZ86tgCy6W4 WfmxCSZunZs/Q== From: "Masami Hiramatsu (Google)" To: Alexei Starovoitov , Steven Rostedt , Florent Revest Cc: linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Sven Schnelle , Alexei Starovoitov , Jiri Olsa , Arnaldo Carvalho de Melo , Daniel Borkmann , Alan Maguire , Mark Rutland , Peter Zijlstra , Thomas Gleixner , Guo Ren Subject: [PATCH v10 29/36] bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled Date: Tue, 7 May 2024 23:13:41 +0900 Message-Id: <171509122161.162236.2569574954668326512.stgit@devnote2> X-Mailer: git-send-email 2.34.1 In-Reply-To: <171509088006.162236.7227326999861366050.stgit@devnote2> References: <171509088006.162236.7227326999861366050.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net From: Masami Hiramatsu (Google) Enable kprobe_multi feature if CONFIG_FPROBE is enabled. The pt_regs is converted from ftrace_regs by ftrace_partial_regs(), thus some registers may always returns 0. But it should be enough for function entry (access arguments) and exit (access return value). Signed-off-by: Masami Hiramatsu (Google) Acked-by: Florent Revest --- Changes in v9: - Avoid wasting memory for bpf_kprobe_multi_pt_regs when CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST=y --- kernel/trace/bpf_trace.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e51a6ef87167..b779f4a83361 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2577,7 +2577,7 @@ static int __init bpf_event_init(void) fs_initcall(bpf_event_init); #endif /* CONFIG_MODULES */ -#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) +#ifdef CONFIG_FPROBE struct bpf_kprobe_multi_link { struct bpf_link link; struct fprobe fp; @@ -2600,6 +2600,13 @@ struct user_syms { char *buf; }; +#ifndef CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs); +#define bpf_kprobe_multi_pt_regs_ptr() this_cpu_ptr(&bpf_kprobe_multi_pt_regs) +#else +#define bpf_kprobe_multi_pt_regs_ptr() (NULL) +#endif + static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt) { unsigned long __user usymbol; @@ -2792,13 +2799,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) static int kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, - unsigned long entry_ip, struct pt_regs *regs) + unsigned long entry_ip, struct ftrace_regs *fregs) { struct bpf_kprobe_multi_run_ctx run_ctx = { .link = link, .entry_ip = entry_ip, }; struct bpf_run_ctx *old_run_ctx; + struct pt_regs *regs; int err; if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { @@ -2809,6 +2817,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, migrate_disable(); rcu_read_lock(); + regs = ftrace_partial_regs(fregs, bpf_kprobe_multi_pt_regs_ptr()); old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); err = bpf_prog_run(link->link.prog, regs); bpf_reset_run_ctx(old_run_ctx); @@ -2826,13 +2835,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, void *data) { struct bpf_kprobe_multi_link *link; - struct pt_regs *regs = ftrace_get_regs(fregs); - - if (!regs) - return 0; link = container_of(fp, struct bpf_kprobe_multi_link, fp); - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); return 0; } @@ -2842,13 +2847,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, void *data) { struct bpf_kprobe_multi_link *link; - struct pt_regs *regs = ftrace_get_regs(fregs); - - if (!regs) - return; link = container_of(fp, struct bpf_kprobe_multi_link, fp); - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); } static int symbols_cmp_r(const void *a, const void *b, const void *priv) @@ -3107,7 +3108,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr kvfree(cookies); return err; } -#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */ +#else /* !CONFIG_FPROBE */ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { return -EOPNOTSUPP;