From nobody Fri Apr 3 00:30:10 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8EF2C54EE9 for ; Tue, 20 Sep 2022 03:37:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229987AbiITDh3 (ORCPT ); Mon, 19 Sep 2022 23:37:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229596AbiITDhS (ORCPT ); Mon, 19 Sep 2022 23:37:18 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id EA4E15A14A for ; Mon, 19 Sep 2022 20:37:16 -0700 (PDT) Received: from linux.localdomain (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8DxReJqNSlj7FseAA--.48978S4; Tue, 20 Sep 2022 11:37:15 +0800 (CST) From: Tiezhu Yang To: Huacai Chen , Masami Hiramatsu Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 2/4] LoongArch: Add kretprobe support Date: Tue, 20 Sep 2022 11:37:12 +0800 Message-Id: <1663645034-967-3-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1663645034-967-1-git-send-email-yangtiezhu@loongson.cn> References: <1663645034-967-1-git-send-email-yangtiezhu@loongson.cn> X-CM-TRANSID: AQAAf8DxReJqNSlj7FseAA--.48978S4 X-Coremail-Antispam: 1UD129KBjvJXoWxGFWxAw1kuFWxJF1UWF4Uurg_yoW5Gw1fpF 9Iyr9xGr45WrZ3ZrZxJ34FvF4S9rn7u3y7GrZrJa4rCFy5XryUJr1xXrW2vFyrGrZYvr1S qF4rJryYkFW7J37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBFb7Iv0xC_KF4lb4IE77IF4wAFF20E14v26r4j6ryUM7CY07I2 0VC2zVCF04k26cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI 8067AKxVWUXwA2048vs2IY020Ec7CjxVAFwI0_JFI_Gr1l8cAvFVAK0II2c7xJM28CjxkF 64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcV CY1x0267AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv 6xkF7I0E14v26F4UJVW0owAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzV Aqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S 6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JMxkIecxEwVAFwVW8GwCF04k20xvY0x 0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E 7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcV C0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF 04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7 CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07jw4SrUUUUU= X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Use the generic kretprobe trampoline handler to add kretprobe support for LoongArch. Signed-off-by: Tiezhu Yang --- arch/loongarch/Kconfig | 1 + arch/loongarch/kernel/kprobes.c | 49 +++++++++++++++++++++++++++++++++++++= +++- 2 files changed, 49 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 6b01073..5f8503a 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -95,6 +95,7 @@ config LOONGARCH select HAVE_IRQ_EXIT_ON_IRQ_STACK select HAVE_IRQ_TIME_ACCOUNTING select HAVE_KPROBES + select HAVE_KRETPROBES select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI select HAVE_PCI diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobe= s.c index b2c73a5..8c3efe5 100644 --- a/arch/loongarch/kernel/kprobes.c +++ b/arch/loongarch/kernel/kprobes.c @@ -303,7 +303,54 @@ int kprobe_exceptions_notify(struct notifier_block *se= lf, } NOKPROBE_SYMBOL(kprobe_exceptions_notify); =20 +/* + * For function-return probes, init_kprobes() establishes a probepoint + * here. When a retprobed function returns, this probe is hit and + * trampoline_probe_handler() runs, calling the kretprobe's handler. + */ +static void __used kretprobe_trampoline_holder(void) +{ + asm volatile(".global __kretprobe_trampoline\n" + "__kretprobe_trampoline:\n" + "nop\n"); +} + +/* Called when the probe at kretprobe trampoline is hit */ +static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) +{ + instruction_pointer(regs) =3D __kretprobe_trampoline_handler(regs, NULL); + /* + * By returning a non-zero value, we are telling + * kprobe_handler() that we don't want the post_handler + * to run (and have re-enabled preemption) + */ + return 1; +} +NOKPROBE_SYMBOL(trampoline_probe_handler); + +static struct kprobe trampoline_p =3D { + .addr =3D (kprobe_opcode_t *)__kretprobe_trampoline, + .pre_handler =3D trampoline_probe_handler +}; + +void arch_prepare_kretprobe(struct kretprobe_instance *ri, + struct pt_regs *regs) +{ + ri->ret_addr =3D (kprobe_opcode_t *)regs->regs[1]; + ri->fp =3D NULL; + + /* Replace the return addr with trampoline addr */ + regs->regs[1] =3D (unsigned long)__kretprobe_trampoline; +} +NOKPROBE_SYMBOL(arch_prepare_kretprobe); + +int arch_trampoline_kprobe(struct kprobe *p) +{ + return p->addr =3D=3D trampoline_p.addr; +} +NOKPROBE_SYMBOL(arch_trampoline_kprobe); + int __init arch_init_kprobes(void) { - return 0; + return register_kprobe(&trampoline_p); } --=20 2.1.0