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Message-ID: <44a7007d-9624-8ac7-e0ab-fab8bdd39848@oracle.com>
Date: Thu, 27 Feb 2020 21:42:02 -0800
From: Joe Jin <joe.jin@...cle.com>
To: Thomas Gleixner <tglx@...utronix.de>,
Marc Zyngier <maz@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc: Joe Jin <joe.jin@...cle.com>
Subject: [PATCH] genirq/debugfs: add new config option for trigger interrupt
from userspace
commit 536e2e34bd00 ("genirq/debugfs: Triggering of interrupts from
userspace") is allowed developer inject interrupts via irq debugfs, which
is very useful during development phase, but on a production system, this
is very dangerous, add new config option, developers can enable it as
needed instead of enabling it by default when irq debugfs is enabled.
Signed-off-by: Joe Jin <joe.jin@...cle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Marc Zyngier <maz@...nel.org>
---
kernel/irq/Kconfig | 15 +++++++++++++++
kernel/irq/debugfs.c | 9 +++++++++
2 files changed, 24 insertions(+)
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index f92d9a687372..00521e896e6c 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -135,6 +135,21 @@ config GENERIC_IRQ_DEBUGFS
If you don't know what to do here, say N.
+config GENERIC_IRQ_DEBUGFS_INJECT_INT
+ bool "Allow trigger interrupts from userspace"
+ depends on DEBUG_FS && GENERIC_IRQ_DEBUGFS
+ default n
+ ---help---
+
+ Allow developers retrigger a (edge-only) interrupt from userspace.
+ To use this feature:
+
+ echo -n trigger > /sys/kernel/debug/irq/irqs/IRQNUM
+
+ WARNING: This is DANGEROUS, and strictly a debug feature.
+
+ If you don't know what to do here, say N.
+
endmenu
config GENERIC_IRQ_MULTI_HANDLER
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index a949bd39e343..56db29bc1acf 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -178,6 +178,7 @@ static int irq_debug_open(struct inode *inode, struct file *file)
return single_open(file, irq_debug_show, inode->i_private);
}
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS_INJECT_INT
static ssize_t irq_debug_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
@@ -223,10 +224,13 @@ static ssize_t irq_debug_write(struct file *file, const char __user *user_buf,
return count;
}
+#endif
static const struct file_operations dfs_irq_ops = {
.open = irq_debug_open,
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS_INJECT_INT
.write = irq_debug_write,
+#endif
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
@@ -249,8 +253,13 @@ void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc)
return;
sprintf(name, "%d", irq);
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS_INJECT_INT
desc->debugfs_file = debugfs_create_file(name, 0644, irq_dir, desc,
&dfs_irq_ops);
+#else
+ desc->debugfs_file = debugfs_create_file(name, 0444, irq_dir, desc,
+ &dfs_irq_ops);
+#endif
}
static int __init irq_debugfs_init(void)
--
2.21.1 (Apple Git-122.3)
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