| Message ID | 20230210044826.9834-8-orlandoch.dev@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | apple-gmux: support MMIO gmux type on T2 Macs | expand |
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) {
Hi, On 2/10/23 21:15, Hans de Goede wrote: > 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 p.s. I just realized I forgot my usual thank you for contributing to the kernel reply to the cover letter before diving into the review (oops). So let me correct that: thank you very much for your work on this! 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) { >
On Fri, 10 Feb 2023 21:23:15 +0100 Hans de Goede <hdegoede@redhat.com> wrote: > Hi, > > On 2/10/23 21:15, Hans de Goede wrote: > > 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. I'll change it to use debugfs instead of sysfs in v2. > > > > Regards, > > > > Hans > > p.s. > > I just realized I forgot my usual thank you for contributing > to the kernel reply to the cover letter before diving into > the review (oops). > > So let me correct that: thank you very much for your work on this! thank you for maintaining and reviewing! > > 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) { > > >
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) {
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) Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com> --- drivers/platform/x86/apple-gmux.c | 129 ++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+)