Hi,
On 2/10/23 05:48, Orlando Chamberlain wrote:
Allow reading gmux ports from userspace. When the unsafe module parameter allow_user_writes is true, writing 1 byte values is also allowed.
For example:
cd /sys/bus/acpi/devices/APP000B:00/physical_node/ echo 4 > gmux_selected_port cat gmux_selected_port_data | xxd -p
Will show the gmux version information (00000005 in this case)
Please use debugfs for this and as part of the conversion drop the #ifdef-s (debugfs has stubs for when not enabled) and drop all the error checking of creating the files, debugfs is deliberately designed to not have any error checking in the setup / teardown code.
This also removes the need for the allow_user_writes parameter replacing it with the new kernel lockdown mechanism. debugfs will automatically block access to writable files when the kernel is in lockdown mode.
Regards,
Hans
Signed-off-by: Orlando Chamberlain orlandoch.dev@gmail.com
drivers/platform/x86/apple-gmux.c | 129 ++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+)
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c index c38d6ef0c15a..756059d48393 100644 --- a/drivers/platform/x86/apple-gmux.c +++ b/drivers/platform/x86/apple-gmux.c @@ -66,6 +66,11 @@ struct apple_gmux_data { enum vga_switcheroo_client_id switch_state_external; enum vga_switcheroo_state power_state; struct completion powerchange_done;
+#ifdef CONFIG_SYSFS
- /* sysfs data */
- int selected_port;
+#endif /* CONFIG_SYSFS */ };
static struct apple_gmux_data *apple_gmux_data; @@ -651,6 +656,121 @@ static void gmux_notify_handler(acpi_handle device, u32 value, void *context) complete(&gmux_data->powerchange_done); }
+/**
- DOC: Sysfs Interface
- gmux ports can be read from userspace as a sysfs interface. For example:
- # echo 4 > /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port
- # cat /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port_data | xxd -p
- 00000005
- Reads 4 bytes from port 4 (GMUX_PORT_VERSION_MAJOR).
- Single byte writes are also supported, however this must be enabled with the
- unsafe allow_user_writes module parameter.
- */
+#ifdef CONFIG_SYSFS
+static bool allow_user_writes; +module_param_unsafe(allow_user_writes, bool, 0); +MODULE_PARM_DESC(allow_user_writes, "Allow userspace to write to gmux ports (default: false) (bool)");
+static ssize_t gmux_selected_port_store(struct device *dev,
struct device_attribute *attr, const char *sysfsbuf, size_t count)+{
- struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
- u8 port;
- if (kstrtou8(sysfsbuf, 10, &port) < 0)
return -EINVAL;- /* On pio gmux's, make sure the user doesn't access too high of a port. */
- if ((gmux_data->config == &apple_gmux_pio) &&
port > (gmux_data->iolen - 4))return -EINVAL;- gmux_data->selected_port = port;
- return count;
+}
+static ssize_t gmux_selected_port_show(struct device *dev,
struct device_attribute *attr, char *sysfsbuf)+{
- struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
- return sysfs_emit(sysfsbuf, "%d\n", gmux_data->selected_port);
+}
+DEVICE_ATTR_RW(gmux_selected_port);
+static ssize_t gmux_selected_port_data_store(struct device *dev,
struct device_attribute *attr, const char *sysfsbuf, size_t count)+{
- struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
- if (count == 1)
gmux_write8(gmux_data, gmux_data->selected_port, *sysfsbuf);- else
return -EINVAL;- return count;
+}
+static ssize_t gmux_selected_port_data_show(struct device *dev,
struct device_attribute *attr, char *sysfsbuf)+{
- struct apple_gmux_data *gmux_data = dev_get_drvdata(dev);
- u32 data;
- data = gmux_read32(gmux_data, gmux_data->selected_port);
- memcpy(sysfsbuf, &data, sizeof(data));
- return sizeof(data);
+}
+struct device_attribute dev_attr_gmux_selected_port_data_rw = __ATTR_RW(gmux_selected_port_data); +struct device_attribute dev_attr_gmux_selected_port_data_ro = __ATTR_RO(gmux_selected_port_data);
+static int gmux_init_sysfs(struct pnp_dev *pnp) +{
- int ret;
- ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port);
- if (ret)
return ret;- if (allow_user_writes)
ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);- else
ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);- if (ret)
device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);- return ret;
+}
+static void gmux_fini_sysfs(struct pnp_dev *pnp) +{
- device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port);
- if (allow_user_writes)
device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw);- else
device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro);+}
+#else
+static int gmux_init_sysfs(struct pnp_dev *pnp) +{
- return 0;
+} +static void gmux_fini_sysfs(struct pnp_dev *pnp) +{ +}
+#endif /* CONFIG_SYSFS */
static int gmux_suspend(struct device *dev) { struct pnp_dev *pnp = to_pnp_dev(dev); @@ -846,8 +966,16 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) goto err_register_handler; }
- ret = gmux_init_sysfs(pnp);
- if (ret) {
pr_err("Failed to register gmux sysfs entries\n");goto err_sysfs;- }
- return 0;
+err_sysfs:
- vga_switcheroo_unregister_handler();
err_register_handler: gmux_disable_interrupts(gmux_data); apple_gmux_data = NULL; @@ -877,6 +1005,7 @@ static void gmux_remove(struct pnp_dev *pnp) { struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
- gmux_fini_sysfs(pnp); vga_switcheroo_unregister_handler(); gmux_disable_interrupts(gmux_data); if (gmux_data->gpe >= 0) {