diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-20 21:20:31 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-20 21:20:31 -0700 |
commit | 5af2344013454640e0133bb62e8cf2e30190a472 (patch) | |
tree | 93495d1eb88d7498dac4747a3d28081c09a69a55 /drivers/hwtracing/intel_th/msu.c | |
parent | 19e36ad292ab24980db64a5ff17973d3118a8fb9 (diff) | |
parent | 725d0123dfff3d7b666cf57f5d29c50addfc99d3 (diff) |
Merge tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char / misc driver updates from Greg KH:
"Here's the big char and misc driver update for 4.7-rc1.
Lots of different tiny driver subsystems have updates here with new
drivers and functionality. Details in the shortlog.
All have been in linux-next with no reported issues for a while"
* tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (125 commits)
mcb: Delete num_cells variable which is not required
mcb: Fixed bar number assignment for the gdd
mcb: Replace ioremap and request_region with the devm version
mcb: Implement bus->dev.release callback
mcb: export bus information via sysfs
mcb: Correctly initialize the bus's device
mei: bus: call mei_cl_read_start under device lock
coresight: etb10: adjust read pointer only when needed
coresight: configuring ETF in FIFO mode when acting as link
coresight: tmc: implementing TMC-ETF AUX space API
coresight: moving struct cs_buffers to header file
coresight: tmc: keep track of memory width
coresight: tmc: make sysFS and Perf mode mutually exclusive
coresight: tmc: dump system memory content only when needed
coresight: tmc: adding mode of operation for link/sinks
coresight: tmc: getting rid of multiple read access
coresight: tmc: allocating memory when needed
coresight: tmc: making prepare/unprepare functions generic
coresight: tmc: splitting driver in ETB/ETF and ETR components
coresight: tmc: cleaning up header file
...
Diffstat (limited to 'drivers/hwtracing/intel_th/msu.c')
-rw-r--r-- | drivers/hwtracing/intel_th/msu.c | 116 |
1 files changed, 68 insertions, 48 deletions
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index d2209147dc89..e8d55a153a65 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -122,7 +122,6 @@ struct msc { atomic_t mmap_count; struct mutex buf_mutex; - struct mutex iter_mutex; struct list_head iter_list; /* config */ @@ -257,23 +256,37 @@ static struct msc_iter *msc_iter_install(struct msc *msc) iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) - return NULL; + return ERR_PTR(-ENOMEM); + + mutex_lock(&msc->buf_mutex); + + /* + * Reading and tracing are mutually exclusive; if msc is + * enabled, open() will fail; otherwise existing readers + * will prevent enabling the msc and the rest of fops don't + * need to worry about it. + */ + if (msc->enabled) { + kfree(iter); + iter = ERR_PTR(-EBUSY); + goto unlock; + } msc_iter_init(iter); iter->msc = msc; - mutex_lock(&msc->iter_mutex); list_add_tail(&iter->entry, &msc->iter_list); - mutex_unlock(&msc->iter_mutex); +unlock: + mutex_unlock(&msc->buf_mutex); return iter; } static void msc_iter_remove(struct msc_iter *iter, struct msc *msc) { - mutex_lock(&msc->iter_mutex); + mutex_lock(&msc->buf_mutex); list_del(&iter->entry); - mutex_unlock(&msc->iter_mutex); + mutex_unlock(&msc->buf_mutex); kfree(iter); } @@ -454,7 +467,6 @@ static void msc_buffer_clear_hw_header(struct msc *msc) { struct msc_window *win; - mutex_lock(&msc->buf_mutex); list_for_each_entry(win, &msc->win_list, entry) { unsigned int blk; size_t hw_sz = sizeof(struct msc_block_desc) - @@ -466,7 +478,6 @@ static void msc_buffer_clear_hw_header(struct msc *msc) memset(&bdesc->hw_tag, 0, hw_sz); } } - mutex_unlock(&msc->buf_mutex); } /** @@ -474,12 +485,15 @@ static void msc_buffer_clear_hw_header(struct msc *msc) * @msc: the MSC device to configure * * Program storage mode, wrapping, burst length and trace buffer address - * into a given MSC. If msc::enabled is set, enable the trace, too. + * into a given MSC. Then, enable tracing and set msc::enabled. + * The latter is serialized on msc::buf_mutex, so make sure to hold it. */ static int msc_configure(struct msc *msc) { u32 reg; + lockdep_assert_held(&msc->buf_mutex); + if (msc->mode > MSC_MODE_MULTI) return -ENOTSUPP; @@ -497,21 +511,19 @@ static int msc_configure(struct msc *msc) reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL); reg &= ~(MSC_MODE | MSC_WRAPEN | MSC_EN | MSC_RD_HDR_OVRD); + reg |= MSC_EN; reg |= msc->mode << __ffs(MSC_MODE); reg |= msc->burst_len << __ffs(MSC_LEN); - /*if (msc->mode == MSC_MODE_MULTI) - reg |= MSC_RD_HDR_OVRD; */ + if (msc->wrap) reg |= MSC_WRAPEN; - if (msc->enabled) - reg |= MSC_EN; iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL); - if (msc->enabled) { - msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI; - intel_th_trace_enable(msc->thdev); - } + msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI; + intel_th_trace_enable(msc->thdev); + msc->enabled = 1; + return 0; } @@ -521,15 +533,14 @@ static int msc_configure(struct msc *msc) * @msc: MSC device to disable * * If @msc is enabled, disable tracing on the switch and then disable MSC - * storage. + * storage. Caller must hold msc::buf_mutex. */ static void msc_disable(struct msc *msc) { unsigned long count; u32 reg; - if (!msc->enabled) - return; + lockdep_assert_held(&msc->buf_mutex); intel_th_trace_disable(msc->thdev); @@ -569,33 +580,35 @@ static void msc_disable(struct msc *msc) static int intel_th_msc_activate(struct intel_th_device *thdev) { struct msc *msc = dev_get_drvdata(&thdev->dev); - int ret = 0; + int ret = -EBUSY; if (!atomic_inc_unless_negative(&msc->user_count)) return -ENODEV; - mutex_lock(&msc->iter_mutex); - if (!list_empty(&msc->iter_list)) - ret = -EBUSY; - mutex_unlock(&msc->iter_mutex); + mutex_lock(&msc->buf_mutex); - if (ret) { - atomic_dec(&msc->user_count); - return ret; - } + /* if there are readers, refuse */ + if (list_empty(&msc->iter_list)) + ret = msc_configure(msc); - msc->enabled = 1; + mutex_unlock(&msc->buf_mutex); + + if (ret) + atomic_dec(&msc->user_count); - return msc_configure(msc); + return ret; } static void intel_th_msc_deactivate(struct intel_th_device *thdev) { struct msc *msc = dev_get_drvdata(&thdev->dev); - msc_disable(msc); - - atomic_dec(&msc->user_count); + mutex_lock(&msc->buf_mutex); + if (msc->enabled) { + msc_disable(msc); + atomic_dec(&msc->user_count); + } + mutex_unlock(&msc->buf_mutex); } /** @@ -1035,8 +1048,8 @@ static int intel_th_msc_open(struct inode *inode, struct file *file) return -EPERM; iter = msc_iter_install(msc); - if (!iter) - return -ENOMEM; + if (IS_ERR(iter)) + return PTR_ERR(iter); file->private_data = iter; @@ -1101,11 +1114,6 @@ static ssize_t intel_th_msc_read(struct file *file, char __user *buf, if (!atomic_inc_unless_negative(&msc->user_count)) return 0; - if (msc->enabled) { - ret = -EBUSY; - goto put_count; - } - if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap) size = msc->single_sz; else @@ -1245,6 +1253,7 @@ static const struct file_operations intel_th_msc_fops = { .read = intel_th_msc_read, .mmap = intel_th_msc_mmap, .llseek = no_llseek, + .owner = THIS_MODULE, }; static int intel_th_msc_init(struct msc *msc) @@ -1254,8 +1263,6 @@ static int intel_th_msc_init(struct msc *msc) msc->mode = MSC_MODE_MULTI; mutex_init(&msc->buf_mutex); INIT_LIST_HEAD(&msc->win_list); - - mutex_init(&msc->iter_mutex); INIT_LIST_HEAD(&msc->iter_list); msc->burst_len = @@ -1393,6 +1400,11 @@ nr_pages_store(struct device *dev, struct device_attribute *attr, do { end = memchr(p, ',', len); s = kstrndup(p, end ? end - p : len, GFP_KERNEL); + if (!s) { + ret = -ENOMEM; + goto free_win; + } + ret = kstrtoul(s, 10, &val); kfree(s); @@ -1473,10 +1485,6 @@ static int intel_th_msc_probe(struct intel_th_device *thdev) if (err) return err; - err = sysfs_create_group(&dev->kobj, &msc_output_group); - if (err) - return err; - dev_set_drvdata(dev, msc); return 0; @@ -1484,7 +1492,18 @@ static int intel_th_msc_probe(struct intel_th_device *thdev) static void intel_th_msc_remove(struct intel_th_device *thdev) { - sysfs_remove_group(&thdev->dev.kobj, &msc_output_group); + struct msc *msc = dev_get_drvdata(&thdev->dev); + int ret; + + intel_th_msc_deactivate(thdev); + + /* + * Buffers should not be used at this point except if the + * output character device is still open and the parent + * device gets detached from its bus, which is a FIXME. + */ + ret = msc_buffer_free_unless_used(msc); + WARN_ON_ONCE(ret); } static struct intel_th_driver intel_th_msc_driver = { @@ -1493,6 +1512,7 @@ static struct intel_th_driver intel_th_msc_driver = { .activate = intel_th_msc_activate, .deactivate = intel_th_msc_deactivate, .fops = &intel_th_msc_fops, + .attr_group = &msc_output_group, .driver = { .name = "msc", .owner = THIS_MODULE, |