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From:   Xiongfeng Wang <wangxiongfeng2@huawei.com>
To:     <wangxiongfeng2@huawei.com>, <james.morse@arm.com>
CC:     <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
Subject: [RFC PATCH] kprobes/arm64: Blacklist functions called in '_sdei_handler'
Date:   Sat, 20 Apr 2019 17:06:57 +0800
Message-ID: <1555751217-54310-1-git-send-email-wangxiongfeng2@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
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Functions called in '_sdei_handler' are needed to be marked as
'nokprobe'.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>

---
When I kprobe 'sdei_smccc_smc', the cpu hungs. I am not sure if it is
becase when SDEI events interrupt EL0, '__sdei_asm_entry_trampoline'
didn't restore vbar_el1 with kernel vectors. Or is it becasue brk
exception corrupt elr_el1 and trust firmware didn't preserve it for us?
---
 drivers/firmware/arm_sdei.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index e6376f9..9cd70d1 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -165,6 +165,7 @@ static int invoke_sdei_fn(unsigned long function_id, unsigned long arg0,
 
 	return err;
 }
+NOKPROBE_SYMBOL(invoke_sdei_fn);
 
 static struct sdei_event *sdei_event_find(u32 event_num)
 {
@@ -879,6 +880,7 @@ static void sdei_smccc_smc(unsigned long function_id,
 {
 	arm_smccc_smc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
 }
+NOKPROBE_SYMBOL(sdei_smccc_smc);
 
 static void sdei_smccc_hvc(unsigned long function_id,
 			   unsigned long arg0, unsigned long arg1,
@@ -887,6 +889,7 @@ static void sdei_smccc_hvc(unsigned long function_id,
 {
 	arm_smccc_hvc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
 }
+NOKPROBE_SYMBOL(sdei_smccc_hvc);
 
 int sdei_register_ghes(struct ghes *ghes, sdei_event_callback *normal_cb,
 		       sdei_event_callback *critical_cb)
-- 
1.7.12.4