[PATCH 5.16 0501/1039] counter: 104-quad-8: Fix persistent enabled events bug
From: Greg Kroah-Hartman
Date: Mon Jan 24 2022 - 18:54:14 EST
From: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
[ Upstream commit c95cc0d95702523f8f361b802c9b7d4eeae07f5d ]
A bug exists if the user executes a COUNTER_ADD_WATCH_IOCTL ioctl call,
and then executes a COUNTER_DISABLE_EVENTS_IOCTL ioctl call. Disabling
the events should disable the 104-QUAD-8 interrupts, but because of this
bug the interrupts are not disabling.
The reason this bug is occurring is because quad8_events_configure() is
called when COUNTER_DISABLE_EVENTS_IOCTL is handled, but the
next_irq_trigger[] array has not been cleared before it is checked in
the loop.
This patch fixes the bug by removing the next_irq_trigger array and
instead utilizing a different algorithm of walking the events_list list
for the current requested events. When a COUNTER_DISABLE_EVENTS_IOCTL is
handled, events_list will be empty and thus all device channels end up
with interrupts disabled.
Fixes: 7aa2ba0df651 ("counter: 104-quad-8: Add IRQ support for the ACCES 104-QUAD-8")
Cc: Syed Nayyar Waris <syednwaris@xxxxxxxxx>
Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
Link: https://lore.kernel.org/r/5fd5731cec1c251acee30eefb7c19160d03c9d39.1640072891.git.vilhelm.gray@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/counter/104-quad-8.c | 82 +++++++++++++++++-------------------
1 file changed, 39 insertions(+), 43 deletions(-)
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 1cbd60aaed697..a97027db0446d 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -14,6 +14,7 @@
#include <linux/interrupt.h>
#include <linux/isa.h>
#include <linux/kernel.h>
+#include <linux/list.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
@@ -44,7 +45,6 @@ MODULE_PARM_DESC(irq, "ACCES 104-QUAD-8 interrupt line numbers");
* @ab_enable: array of A and B inputs enable configurations
* @preset_enable: array of set_to_preset_on_index attribute configurations
* @irq_trigger: array of current IRQ trigger function configurations
- * @next_irq_trigger: array of next IRQ trigger function configurations
* @synchronous_mode: array of index function synchronous mode configurations
* @index_polarity: array of index function polarity configurations
* @cable_fault_enable: differential encoder cable status enable configurations
@@ -61,7 +61,6 @@ struct quad8 {
unsigned int ab_enable[QUAD8_NUM_COUNTERS];
unsigned int preset_enable[QUAD8_NUM_COUNTERS];
unsigned int irq_trigger[QUAD8_NUM_COUNTERS];
- unsigned int next_irq_trigger[QUAD8_NUM_COUNTERS];
unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
unsigned int index_polarity[QUAD8_NUM_COUNTERS];
unsigned int cable_fault_enable;
@@ -390,7 +389,6 @@ static int quad8_action_read(struct counter_device *counter,
}
enum {
- QUAD8_EVENT_NONE = -1,
QUAD8_EVENT_CARRY = 0,
QUAD8_EVENT_COMPARE = 1,
QUAD8_EVENT_CARRY_BORROW = 2,
@@ -402,34 +400,49 @@ static int quad8_events_configure(struct counter_device *counter)
struct quad8 *const priv = counter->priv;
unsigned long irq_enabled = 0;
unsigned long irqflags;
- size_t channel;
+ struct counter_event_node *event_node;
+ unsigned int next_irq_trigger;
unsigned long ior_cfg;
unsigned long base_offset;
spin_lock_irqsave(&priv->lock, irqflags);
- /* Enable interrupts for the requested channels, disable for the rest */
- for (channel = 0; channel < QUAD8_NUM_COUNTERS; channel++) {
- if (priv->next_irq_trigger[channel] == QUAD8_EVENT_NONE)
- continue;
+ list_for_each_entry(event_node, &counter->events_list, l) {
+ switch (event_node->event) {
+ case COUNTER_EVENT_OVERFLOW:
+ next_irq_trigger = QUAD8_EVENT_CARRY;
+ break;
+ case COUNTER_EVENT_THRESHOLD:
+ next_irq_trigger = QUAD8_EVENT_COMPARE;
+ break;
+ case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
+ next_irq_trigger = QUAD8_EVENT_CARRY_BORROW;
+ break;
+ case COUNTER_EVENT_INDEX:
+ next_irq_trigger = QUAD8_EVENT_INDEX;
+ break;
+ default:
+ /* should never reach this path */
+ spin_unlock_irqrestore(&priv->lock, irqflags);
+ return -EINVAL;
+ }
- if (priv->irq_trigger[channel] != priv->next_irq_trigger[channel]) {
- /* Save new IRQ function configuration */
- priv->irq_trigger[channel] = priv->next_irq_trigger[channel];
+ /* Skip configuration if it is the same as previously set */
+ if (priv->irq_trigger[event_node->channel] == next_irq_trigger)
+ continue;
- /* Load configuration to I/O Control Register */
- ior_cfg = priv->ab_enable[channel] |
- priv->preset_enable[channel] << 1 |
- priv->irq_trigger[channel] << 3;
- base_offset = priv->base + 2 * channel + 1;
- outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
- }
+ /* Save new IRQ function configuration */
+ priv->irq_trigger[event_node->channel] = next_irq_trigger;
- /* Reset next IRQ trigger function configuration */
- priv->next_irq_trigger[channel] = QUAD8_EVENT_NONE;
+ /* Load configuration to I/O Control Register */
+ ior_cfg = priv->ab_enable[event_node->channel] |
+ priv->preset_enable[event_node->channel] << 1 |
+ priv->irq_trigger[event_node->channel] << 3;
+ base_offset = priv->base + 2 * event_node->channel + 1;
+ outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
/* Enable IRQ line */
- irq_enabled |= BIT(channel);
+ irq_enabled |= BIT(event_node->channel);
}
outb(irq_enabled, priv->base + QUAD8_REG_INDEX_INTERRUPT);
@@ -442,35 +455,20 @@ static int quad8_events_configure(struct counter_device *counter)
static int quad8_watch_validate(struct counter_device *counter,
const struct counter_watch *watch)
{
- struct quad8 *const priv = counter->priv;
+ struct counter_event_node *event_node;
if (watch->channel > QUAD8_NUM_COUNTERS - 1)
return -EINVAL;
switch (watch->event) {
case COUNTER_EVENT_OVERFLOW:
- if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
- priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_CARRY;
- else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_CARRY)
- return -EINVAL;
- return 0;
case COUNTER_EVENT_THRESHOLD:
- if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
- priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_COMPARE;
- else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_COMPARE)
- return -EINVAL;
- return 0;
case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
- if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
- priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_CARRY_BORROW;
- else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_CARRY_BORROW)
- return -EINVAL;
- return 0;
case COUNTER_EVENT_INDEX:
- if (priv->next_irq_trigger[watch->channel] == QUAD8_EVENT_NONE)
- priv->next_irq_trigger[watch->channel] = QUAD8_EVENT_INDEX;
- else if (priv->next_irq_trigger[watch->channel] != QUAD8_EVENT_INDEX)
- return -EINVAL;
+ list_for_each_entry(event_node, &counter->next_events_list, l)
+ if (watch->channel == event_node->channel &&
+ watch->event != event_node->event)
+ return -EINVAL;
return 0;
default:
return -EINVAL;
@@ -1183,8 +1181,6 @@ static int quad8_probe(struct device *dev, unsigned int id)
outb(QUAD8_CTR_IOR, base_offset + 1);
/* Disable index function; negative index polarity */
outb(QUAD8_CTR_IDR, base_offset + 1);
- /* Initialize next IRQ trigger function configuration */
- priv->next_irq_trigger[i] = QUAD8_EVENT_NONE;
}
/* Disable Differential Encoder Cable Status for all channels */
outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
--
2.34.1