From patchwork Sun Jul 14 08:27:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naveen N Rao X-Patchwork-Id: 13732618 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 7B9214595B; Sun, 14 Jul 2024 08:29:29 +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=1720945769; cv=none; b=ggZ5/RCE16HJFHuvT66wRaAODz0L0zSjC9nahQLEAAxqa1Ycsv8KvJICk+Src1FkgYKftrtToCnc9smbvPSXc4Zesyf0zQy1CVxPXmtTIKY3d8J1jvWsvkDPJ160f+GSuqN3ELCi+iUWIShH/FZHx0hY40QhjOh5e8ZkOEWAoag= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720945769; c=relaxed/simple; bh=Yw7BK5ZSzIqUwdH+xzRKsshvO4agK2xzXRxs7K0POPk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rCk54CLbnntJb9rAvaeWvo35/GK9CL/hnL/Y+tu6Dxr0mJOkvwhGEMl93EDJVFQKxEiq2LjPa5OZIRGPwLqB5nTa3DJOp53TxfDS8S5/405PMZrEU3eNX9ll32QeeT+ihpUwPcCo8AhsvirnTUe6E4+JGfL542pQq0EuLu3BtCg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iu+S2/CO; 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="iu+S2/CO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F9C0C4AF0A; Sun, 14 Jul 2024 08:29:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720945769; bh=Yw7BK5ZSzIqUwdH+xzRKsshvO4agK2xzXRxs7K0POPk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iu+S2/COmExD2t5/fDyfq7l4ZVCYt9JRCq2RzN28BeGCP0NBLWxXIADnph3qHr7++ I5YmI/fYuJrPObs+vDblAtzHtWjk5PfERvuquk4AGn1wYo6u6O2rRRNjCfNf2FiodN T1JjYiM3b7+z2wgBy83gtr8Je2ojhXe+ppbathOWCyvlKT5FmP0QtZ6ckhnvSQKqyW e1JprOL03fEhjRNxXiby58fOoWl6spkopXuA5gKtgpz3YpJYdFsXWskVdin143+Ak8 TuuHmshZ2OA4nq3Lx/g6Why2YfMiFMWnqBeSUEUKuFXPkh2MRYVBTf1n80ZxvxkTSN FDhfLN4ImhX0Q== From: Naveen N Rao To: , , , linux-kbuild@vger.kernel.org, Cc: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masahiro Yamada , Hari Bathini , Mahesh Salgaonkar , Vishal Chourasia Subject: [RFC PATCH v4 02/17] powerpc/kprobes: Use ftrace to determine if a probe is at function entry Date: Sun, 14 Jul 2024 13:57:38 +0530 Message-ID: X-Mailer: git-send-email 2.45.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Rather than hard-coding the offset into a function to be used to determine if a kprobe is at function entry, use ftrace_location() to determine the ftrace location within the function and categorize all instructions till that offset to be function entry. For functions that cannot be traced, we fall back to using a fixed offset of 8 (two instructions) to categorize a probe as being at function entry for 64-bit elfv2, unless we are using pcrel. Acked-by: Masami Hiramatsu (Google) Signed-off-by: Naveen N Rao --- arch/powerpc/kernel/kprobes.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 14c5ddec3056..ca204f4f21c1 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -105,24 +105,22 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset) return addr; } -static bool arch_kprobe_on_func_entry(unsigned long offset) +static bool arch_kprobe_on_func_entry(unsigned long addr, unsigned long offset) { -#ifdef CONFIG_PPC64_ELF_ABI_V2 -#ifdef CONFIG_KPROBES_ON_FTRACE - return offset <= 16; -#else - return offset <= 8; -#endif -#else + unsigned long ip = ftrace_location(addr); + + if (ip) + return offset <= (ip - addr); + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + return offset <= 8; return !offset; -#endif } /* XXX try and fold the magic of kprobe_lookup_name() in this */ kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry) { - *on_func_entry = arch_kprobe_on_func_entry(offset); + *on_func_entry = arch_kprobe_on_func_entry(addr, offset); return (kprobe_opcode_t *)(addr + offset); }