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Code Issues Projects Releases Wiki Activity

coresight: add spinlock across stm channel allocation 

There appears to be a race condition during stm channel allocation where
two processes running in parallel get same channel. Fix this by adding a
spinlock across channel allocation logic until we figure out a root cause
of this issue.

Change-Id: Ifcc655957adae3c58d8b329d8cd5c0551a26d5c6
Signed-off-by: Sarangdhar Joshi <spjoshi@codeaurora.org>
This commit is contained in:
Sarangdhar Joshi 2014-07-25 11:07:19 -07:00
parent 763e35c98f
commit 719767d522
1 changed files with 33 additions and 17 deletions
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50
drivers/coresight/coresight-stm.c
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@ -1,4 +1,4 @@
/* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
/* Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
@ -148,12 +148,13 @@ static struct stm_drvdata *stmdrvdata;
static int stm_hwevent_isenable(struct stm_drvdata *drvdata)
{
int ret = 0;
unsigned long flags;
spin_lock(&drvdata->spinlock);
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->enable)
if (BVAL(stm_readl(drvdata, STMHEMCR), 0))
ret = stm_readl(drvdata, STMHEER) == 0 ? 0 : 1;
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return ret;
}
@ -175,13 +176,14 @@ static void __stm_hwevent_enable(struct stm_drvdata *drvdata)
static int stm_hwevent_enable(struct stm_drvdata *drvdata)
{
int ret = 0;
unsigned long flags;
spin_lock(&drvdata->spinlock);
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->enable)
__stm_hwevent_enable(drvdata);
else
ret = -EINVAL;
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return ret;
}
@ -189,11 +191,12 @@ static int stm_hwevent_enable(struct stm_drvdata *drvdata)
static int stm_port_isenable(struct stm_drvdata *drvdata)
{
int ret = 0;
unsigned long flags;
spin_lock(&drvdata->spinlock);
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->enable)
ret = stm_readl(drvdata, STMSPER) == 0 ? 0 : 1;
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return ret;
}
@ -211,13 +214,14 @@ static void __stm_port_enable(struct stm_drvdata *drvdata)
static int stm_port_enable(struct stm_drvdata *drvdata)
{
int ret = 0;
unsigned long flags;
spin_lock(&drvdata->spinlock);
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->enable)
__stm_port_enable(drvdata);
else
ret = -EINVAL;
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return ret;
}
@ -240,15 +244,16 @@ static int stm_enable(struct coresight_device *csdev)
{
struct stm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
int ret;
unsigned long flags;
ret = clk_prepare_enable(drvdata->clk);
if (ret)
return ret;
spin_lock(&drvdata->spinlock);
spin_lock_irqsave(&drvdata->spinlock, flags);
__stm_enable(drvdata);
drvdata->enable = true;
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
dev_info(drvdata->dev, "STM tracing enabled\n");
return 0;
@ -267,10 +272,12 @@ static void __stm_hwevent_disable(struct stm_drvdata *drvdata)
static void stm_hwevent_disable(struct stm_drvdata *drvdata)
{
spin_lock(&drvdata->spinlock);
unsigned long flags;
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->enable)
__stm_hwevent_disable(drvdata);
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
}
static void __stm_port_disable(struct stm_drvdata *drvdata)
@ -285,10 +292,12 @@ static void __stm_port_disable(struct stm_drvdata *drvdata)
static void stm_port_disable(struct stm_drvdata *drvdata)
{
spin_lock(&drvdata->spinlock);
unsigned long flags;
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->enable)
__stm_port_disable(drvdata);
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
}
static void __stm_disable(struct stm_drvdata *drvdata)
@ -306,11 +315,12 @@ static void __stm_disable(struct stm_drvdata *drvdata)
static void stm_disable(struct coresight_device *csdev)
{
struct stm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
unsigned long flags;
spin_lock(&drvdata->spinlock);
spin_lock_irqsave(&drvdata->spinlock, flags);
__stm_disable(drvdata);
drvdata->enable = false;
spin_unlock(&drvdata->spinlock);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
/* Wait for 100ms so that pending data has been written to HW */
msleep(100);
@ -333,12 +343,15 @@ static uint32_t stm_channel_alloc(uint32_t off)
{
struct stm_drvdata *drvdata = stmdrvdata;
uint32_t ch;
unsigned long flags;
spin_lock_irqsave(&drvdata->spinlock, flags);
do {
ch = find_next_zero_bit(drvdata->chs.bitmap,
NR_STM_CHANNEL, off);
} while ((ch < NR_STM_CHANNEL) &&
test_and_set_bit(ch, drvdata->chs.bitmap));
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return ch;
}
@ -346,8 +359,11 @@ static uint32_t stm_channel_alloc(uint32_t off)
static void stm_channel_free(uint32_t ch)
{
struct stm_drvdata *drvdata = stmdrvdata;
unsigned long flags;
spin_lock_irqsave(&drvdata->spinlock, flags);
clear_bit(ch, drvdata->chs.bitmap);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
}
static int stm_send_64bit(void *addr, const void *data, uint32_t size)