Hi
On Fri, Nov 1, 2013 at 9:16 PM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
> As we painfully noticed during the 3.12 merge-window our
> EVIOCGABS/EVIOCSABS API is limited to ABS_MAX<=0x3f. We tried several
> hacks to work around it but if we ever decide to increase ABS_MAX, the
> EVIOCSABS ioctl ABI might overflow into the next byte causing horrible
> misinterpretations in the kernel that we cannot catch.
>
> Therefore, we decided to go with ABS_MAX2/CNT2 and introduce two new
> ioctls to get/set abs-params. They no longer encode the ABS code in the
> ioctl number and thus allow up to 4 billion ABS codes.
>
> The new API also allows to query multiple ABS values with one call. To
> allow EVIOCSABS2(code = 0, cnt = ABS_CNT2) we need to silently ignore
> writes to ABS_MT_SLOT. Other than that, semantics are the same as for the
> legacy API.
I'm currently having a hard time making this properly work with
backwards-compatibility in mind. It can get really hairy to properly
detect whether a kernel supports ABS2 or not (during runtime). Any
objections to increasing the EVDEV version field? User-space could
then easily know whether EVIOCGABS2 is supported.
Just as a note: the libevdev test-suite runs just fine with this
patch, so at least it shouldn't break backwards-compat this time.
Anyway, I would feel a lot better if we can let this stay in
linux-next for one cycle.
Thanks
David
> Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
> ---
> drivers/hid/hid-debug.c | 2 +-
> drivers/hid/hid-input.c | 2 +-
> drivers/input/evdev.c | 88 +++++++++++++++++++++++++++++++-
> drivers/input/input.c | 14 ++---
> drivers/input/keyboard/goldfish_events.c | 6 +--
> drivers/input/keyboard/hil_kbd.c | 2 +-
> drivers/input/misc/uinput.c | 6 +--
> include/linux/hid.h | 2 +-
> include/linux/input.h | 6 +--
> include/uapi/linux/input.h | 37 +++++++++++++-
> include/uapi/linux/uinput.h | 2 +-
> 11 files changed, 144 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c
> index 8453214..d32fa30 100644
> --- a/drivers/hid/hid-debug.c
> +++ b/drivers/hid/hid-debug.c
> @@ -862,7 +862,7 @@ static const char *relatives[REL_MAX + 1] = {
> [REL_WHEEL] = "Wheel", [REL_MISC] = "Misc",
> };
>
> -static const char *absolutes[ABS_CNT] = {
> +static const char *absolutes[ABS_CNT2] = {
> [ABS_X] = "X", [ABS_Y] = "Y",
> [ABS_Z] = "Z", [ABS_RX] = "Rx",
> [ABS_RY] = "Ry", [ABS_RZ] = "Rz",
> diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> index d97f232..a02721c 100644
> --- a/drivers/hid/hid-input.c
> +++ b/drivers/hid/hid-input.c
> @@ -1300,7 +1300,7 @@ static bool hidinput_has_been_populated(struct hid_input *hidinput)
> for (i = 0; i < BITS_TO_LONGS(REL_CNT); i++)
> r |= hidinput->input->relbit[i];
>
> - for (i = 0; i < BITS_TO_LONGS(ABS_CNT); i++)
> + for (i = 0; i < BITS_TO_LONGS(ABS_CNT2); i++)
> r |= hidinput->input->absbit[i];
>
> for (i = 0; i < BITS_TO_LONGS(MSC_CNT); i++)
> diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> index b6ded17..ffe65fd 100644
> --- a/drivers/input/evdev.c
> +++ b/drivers/input/evdev.c
> @@ -635,7 +635,7 @@ static int handle_eviocgbit(struct input_dev *dev,
> case 0: bits = dev->evbit; len = EV_MAX; break;
> case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
> case EV_REL: bits = dev->relbit; len = REL_MAX; break;
> - case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
> + case EV_ABS: bits = dev->absbit; len = ABS_MAX2; break;
> case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
> case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
> case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
> @@ -663,6 +663,86 @@ static int handle_eviocgbit(struct input_dev *dev,
> }
> #undef OLD_KEY_MAX
>
> +static int evdev_handle_get_abs2(struct input_dev *dev, void __user *p)
> +{
> + u32 code, cnt, i;
> + struct input_absinfo2 __user *pinfo = p;
> + struct input_absinfo abs;
> +
> + if (!dev->absinfo)
> + return -EINVAL;
> +
> + if (copy_from_user(&code, &pinfo->code, sizeof(code)))
> + return -EFAULT;
> + if (copy_from_user(&cnt, &pinfo->cnt, sizeof(cnt)))
> + return -EFAULT;
> +
> + if (!cnt || code > ABS_MAX2 || cnt > ABS_CNT2)
> + return -EINVAL;
> + if (code + cnt > ABS_MAX2)
> + return -EINVAL;
> +
> + for (i = 0; i < cnt; ++i) {
> + /*
> + * Take event lock to ensure that we are not
> + * copying data while EVIOCSABS2 changes it.
> + * Might be inconsistent, otherwise.
> + */
> + spin_lock_irq(&dev->event_lock);
> + abs = dev->absinfo[code + i];
> + spin_unlock_irq(&dev->event_lock);
> +
> + if (copy_to_user(&pinfo->info[i], &abs, sizeof(abs)))
> + return -EFAULT;
> + }
> +
> + return 0;
> +}
> +
> +static int evdev_handle_set_abs2(struct input_dev *dev, void __user *p)
> +{
> + struct input_absinfo2 __user *pinfo = p;
> + struct input_absinfo *abs;
> + u32 code, cnt, i;
> + size_t size;
> +
> + if (!dev->absinfo)
> + return -EINVAL;
> +
> + if (copy_from_user(&code, &pinfo->code, sizeof(code)))
> + return -EFAULT;
> + if (copy_from_user(&cnt, &pinfo->cnt, sizeof(cnt)))
> + return -EFAULT;
> +
> + if (!cnt || code > ABS_MAX2 || cnt > ABS_CNT2)
> + return -EINVAL;
> + if (code + cnt > ABS_MAX2)
> + return -EINVAL;
> +
> + size = cnt * sizeof(*abs);
> + abs = memdup_user(&pinfo->info[0], size);
> + if (IS_ERR(abs))
> + return PTR_ERR(abs);
> +
> + /*
> + * Take event lock to ensure that we are not
> + * changing device parameters in the middle
> + * of event.
> + */
> + spin_lock_irq(&dev->event_lock);
> + for (i = 0; i < cnt; ++i) {
> + /* silently drop ABS_MT_SLOT */
> + if (code + i == ABS_MT_SLOT)
> + continue;
> +
> + dev->absinfo[code + i] = abs[i];
> + }
> + spin_unlock_irq(&dev->event_lock);
> +
> + kfree(abs);
> + return 0;
> +}
> +
> static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
> {
> struct input_keymap_entry ke = {
> @@ -890,6 +970,12 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
> client->clkid = i;
> return 0;
>
> + case EVIOCGABS2:
> + return evdev_handle_get_abs2(dev, p);
> +
> + case EVIOCSABS2:
> + return evdev_handle_set_abs2(dev, p);
> +
> case EVIOCGKEYCODE:
> return evdev_handle_get_keycode(dev, p);
>
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index c044699..bc88f17 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -305,7 +305,7 @@ static int input_get_disposition(struct input_dev *dev,
> break;
>
> case EV_ABS:
> - if (is_event_supported(code, dev->absbit, ABS_MAX))
> + if (is_event_supported(code, dev->absbit, ABS_MAX2))
> disposition = input_handle_abs_event(dev, code, &value);
>
> break;
> @@ -474,7 +474,7 @@ EXPORT_SYMBOL(input_inject_event);
> void input_alloc_absinfo(struct input_dev *dev)
> {
> if (!dev->absinfo)
> - dev->absinfo = kcalloc(ABS_CNT, sizeof(struct input_absinfo),
> + dev->absinfo = kcalloc(ABS_CNT2, sizeof(struct input_absinfo),
> GFP_KERNEL);
>
> WARN(!dev->absinfo, "%s(): kcalloc() failed?\n", __func__);
> @@ -954,7 +954,7 @@ static const struct input_device_id *input_match_device(struct input_handler *ha
> if (!bitmap_subset(id->relbit, dev->relbit, REL_MAX))
> continue;
>
> - if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX))
> + if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX2))
> continue;
>
> if (!bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX))
> @@ -1147,7 +1147,7 @@ static int input_devices_seq_show(struct seq_file *seq, void *v)
> if (test_bit(EV_REL, dev->evbit))
> input_seq_print_bitmap(seq, "REL", dev->relbit, REL_MAX);
> if (test_bit(EV_ABS, dev->evbit))
> - input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX);
> + input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX2);
> if (test_bit(EV_MSC, dev->evbit))
> input_seq_print_bitmap(seq, "MSC", dev->mscbit, MSC_MAX);
> if (test_bit(EV_LED, dev->evbit))
> @@ -1333,7 +1333,7 @@ static int input_print_modalias(char *buf, int size, struct input_dev *id,
> len += input_print_modalias_bits(buf + len, size - len,
> 'r', id->relbit, 0, REL_MAX);
> len += input_print_modalias_bits(buf + len, size - len,
> - 'a', id->absbit, 0, ABS_MAX);
> + 'a', id->absbit, 0, ABS_MAX2);
> len += input_print_modalias_bits(buf + len, size - len,
> 'm', id->mscbit, 0, MSC_MAX);
> len += input_print_modalias_bits(buf + len, size - len,
> @@ -1592,7 +1592,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
> if (test_bit(EV_REL, dev->evbit))
> INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
> if (test_bit(EV_ABS, dev->evbit))
> - INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
> + INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX2);
> if (test_bit(EV_MSC, dev->evbit))
> INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
> if (test_bit(EV_LED, dev->evbit))
> @@ -1924,7 +1924,7 @@ static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
>
> events = mt_slots + 1; /* count SYN_MT_REPORT and SYN_REPORT */
>
> - for (i = 0; i < ABS_CNT; i++) {
> + for (i = 0; i < ABS_CNT2; i++) {
> if (test_bit(i, dev->absbit)) {
> if (input_is_mt_axis(i))
> events += mt_slots;
> diff --git a/drivers/input/keyboard/goldfish_events.c b/drivers/input/keyboard/goldfish_events.c
> index 9f60a2e..9999cea 100644
> --- a/drivers/input/keyboard/goldfish_events.c
> +++ b/drivers/input/keyboard/goldfish_events.c
> @@ -90,8 +90,8 @@ static void events_import_abs_params(struct event_dev *edev)
> __raw_writel(PAGE_ABSDATA, addr + REG_SET_PAGE);
>
> count = __raw_readl(addr + REG_LEN) / sizeof(val);
> - if (count > ABS_MAX)
> - count = ABS_MAX;
> + if (count > ABS_MAX2)
> + count = ABS_MAX2;
>
> for (i = 0; i < count; i++) {
> if (!test_bit(i, input_dev->absbit))
> @@ -158,7 +158,7 @@ static int events_probe(struct platform_device *pdev)
> events_import_bits(edev, input_dev->evbit, EV_SYN, EV_MAX);
> events_import_bits(edev, input_dev->keybit, EV_KEY, KEY_MAX);
> events_import_bits(edev, input_dev->relbit, EV_REL, REL_MAX);
> - events_import_bits(edev, input_dev->absbit, EV_ABS, ABS_MAX);
> + events_import_bits(edev, input_dev->absbit, EV_ABS, ABS_MAX2);
> events_import_bits(edev, input_dev->mscbit, EV_MSC, MSC_MAX);
> events_import_bits(edev, input_dev->ledbit, EV_LED, LED_MAX);
> events_import_bits(edev, input_dev->sndbit, EV_SND, SND_MAX);
> diff --git a/drivers/input/keyboard/hil_kbd.c b/drivers/input/keyboard/hil_kbd.c
> index 589e3c2..4e4e010 100644
> --- a/drivers/input/keyboard/hil_kbd.c
> +++ b/drivers/input/keyboard/hil_kbd.c
> @@ -387,7 +387,7 @@ static void hil_dev_pointer_setup(struct hil_dev *ptr)
> 0, HIL_IDD_AXIS_MAX(idd, i - 3), 0, 0);
>
> #ifdef TABLET_AUTOADJUST
> - for (i = 0; i < ABS_MAX; i++) {
> + for (i = 0; i < ABS_MAX2; i++) {
> int diff = input_abs_get_max(input_dev, ABS_X + i) / 10;
> input_abs_set_min(input_dev, ABS_X + i,
> input_abs_get_min(input_dev, ABS_X + i) + diff);
> diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
> index 3cd84d2..2f7355e 100644
> --- a/drivers/input/misc/uinput.c
> +++ b/drivers/input/misc/uinput.c
> @@ -311,7 +311,7 @@ static int uinput_validate_absbits(struct input_dev *dev)
> unsigned int cnt;
> int retval = 0;
>
> - for (cnt = 0; cnt < ABS_CNT; cnt++) {
> + for (cnt = 0; cnt < ABS_CNT2; cnt++) {
> int min, max;
> if (!test_bit(cnt, dev->absbit))
> continue;
> @@ -474,7 +474,7 @@ static int uinput_setup_device2(struct uinput_device *udev,
> return -EINVAL;
>
> /* rough check to avoid huge kernel space allocations */
> - max = ABS_CNT * sizeof(*user_dev2->abs) + sizeof(*user_dev2);
> + max = ABS_CNT2 * sizeof(*user_dev2->abs) + sizeof(*user_dev2);
> if (count > max)
> return -EINVAL;
>
> @@ -770,7 +770,7 @@ static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
> break;
>
> case UI_SET_ABSBIT:
> - retval = uinput_set_bit(arg, absbit, ABS_MAX);
> + retval = uinput_set_bit(arg, absbit, ABS_MAX2);
> break;
>
> case UI_SET_MSCBIT:
> diff --git a/include/linux/hid.h b/include/linux/hid.h
> index 31b9d29..c21d8bb 100644
> --- a/include/linux/hid.h
> +++ b/include/linux/hid.h
> @@ -828,7 +828,7 @@ static inline void hid_map_usage(struct hid_input *hidinput,
> switch (type) {
> case EV_ABS:
> *bit = input->absbit;
> - *max = ABS_MAX;
> + *max = ABS_MAX2;
> break;
> case EV_REL:
> *bit = input->relbit;
> diff --git a/include/linux/input.h b/include/linux/input.h
> index 82ce323..c6add6f 100644
> --- a/include/linux/input.h
> +++ b/include/linux/input.h
> @@ -129,7 +129,7 @@ struct input_dev {
> unsigned long evbit[BITS_TO_LONGS(EV_CNT)];
> unsigned long keybit[BITS_TO_LONGS(KEY_CNT)];
> unsigned long relbit[BITS_TO_LONGS(REL_CNT)];
> - unsigned long absbit[BITS_TO_LONGS(ABS_CNT)];
> + unsigned long absbit[BITS_TO_LONGS(ABS_CNT2)];
> unsigned long mscbit[BITS_TO_LONGS(MSC_CNT)];
> unsigned long ledbit[BITS_TO_LONGS(LED_CNT)];
> unsigned long sndbit[BITS_TO_LONGS(SND_CNT)];
> @@ -210,8 +210,8 @@ struct input_dev {
> #error "REL_MAX and INPUT_DEVICE_ID_REL_MAX do not match"
> #endif
>
> -#if ABS_MAX != INPUT_DEVICE_ID_ABS_MAX
> -#error "ABS_MAX and INPUT_DEVICE_ID_ABS_MAX do not match"
> +#if ABS_MAX2 != INPUT_DEVICE_ID_ABS_MAX
> +#error "ABS_MAX2 and INPUT_DEVICE_ID_ABS_MAX do not match"
> #endif
>
> #if MSC_MAX != INPUT_DEVICE_ID_MSC_MAX
> diff --git a/include/uapi/linux/input.h b/include/uapi/linux/input.h
> index a372627..9e525f9 100644
> --- a/include/uapi/linux/input.h
> +++ b/include/uapi/linux/input.h
> @@ -74,6 +74,27 @@ struct input_absinfo {
> };
>
> /**
> + * struct input_absinfo2 - used by EVIOC[G/S]ABS2 ioctls
> + * @code: First ABS code to query
> + * @cnt: Number of ABS codes to query starting at @code
> + * @info: #@cnt absinfo structures to get/set abs parameters for all codes
> + *
> + * This structure is used by the new EVIOC[G/S]ABS2 ioctls which
> + * do the same as the old EVIOC[G/S]ABS ioctls but avoid encoding
> + * the ABS code in the ioctl number. This allows a much wider
> + * range of ABS codes. Furthermore, it allows to query multiple codes with a
> + * single call.
> + *
> + * Note that this silently drops any requests to set ABS_MT_SLOT. Hence, it is
> + * allowed to call this with code=0 cnt=ABS_CNT2.
> + */
> +struct input_absinfo2 {
> + __u32 code;
> + __u32 cnt;
> + struct input_absinfo info[1];
> +};
> +
> +/**
> * struct input_keymap_entry - used by EVIOCGKEYCODE/EVIOCSKEYCODE ioctls
> * @scancode: scancode represented in machine-endian form.
> * @len: length of the scancode that resides in @scancode buffer.
> @@ -153,6 +174,8 @@ struct input_keymap_entry {
>
> #define EVIOCGRAB _IOW('E', 0x90, int) /* Grab/Release device */
> #define EVIOCREVOKE _IOW('E', 0x91, int) /* Revoke device access */
> +#define EVIOCGABS2 _IOR('E', 0x92, struct input_absinfo2) /* get abs value/limits */
> +#define EVIOCSABS2 _IOW('E', 0x93, struct input_absinfo2) /* set abs value/limits */
>
> #define EVIOCSCLOCKID _IOW('E', 0xa0, int) /* Set clockid to be used for timestamps */
>
> @@ -832,11 +855,23 @@ struct input_keymap_entry {
> #define ABS_MT_TOOL_X 0x3c /* Center X tool position */
> #define ABS_MT_TOOL_Y 0x3d /* Center Y tool position */
>
> -
> +/*
> + * ABS_MAX/CNT is limited to a maximum of 0x3f due to the design of EVIOCGABS
> + * and EVIOCSABS ioctls. Other kernel APIs like uinput also hardcoded it. Do
> + * not modify this value and instead use the extended ABS_MAX2/CNT2 API.
> + */
> #define ABS_MAX 0x3f
> #define ABS_CNT (ABS_MAX+1)
>
> /*
> + * Due to API restrictions the legacy evdev API only supports ABS values up to
> + * ABS_MAX/CNT. Use the extended *ABS2 ioctls to operate on any ABS values in
> + * between ABS_MAX and ABS_MAX2.
> + */
> +#define ABS_MAX2 0x3f
> +#define ABS_CNT2 (ABS_MAX2+1)
> +
> +/*
> * Switch events
> */
>
> diff --git a/include/uapi/linux/uinput.h b/include/uapi/linux/uinput.h
> index c2e8710..27ee521 100644
> --- a/include/uapi/linux/uinput.h
> +++ b/include/uapi/linux/uinput.h
> @@ -140,7 +140,7 @@ struct uinput_user_dev2 {
> char name[UINPUT_MAX_NAME_SIZE];
> struct input_id id;
> __u32 ff_effects_max;
> - struct input_absinfo abs[ABS_CNT];
> + struct input_absinfo abs[ABS_CNT2];
> };
>
> #endif /* _UAPI__UINPUT_H_ */
> --
> 1.8.4.1
>
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