kernel/linux.git/drivers/ptp/ptp_vmclock.c, branch v7.0.10

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

ptp: ptp_vmclock: return TAI not UTC

2026-02-03T02:06:01+00:00

To output UTC would involve complex calculations about whether the time elapsed since the reference time has crossed the end of the month when a leap second takes effect. I've prototyped that, but it made me sad. Much better to report TAI, which is what PHCs should do anyway. And much much simpler. Signed-off-by: David Woodhouse Signed-off-by: Babis Chalios Tested-by: Takahiro Itazuri Link: https://patch.msgid.link/20260130173704.12575-8-itazur@amazon.com Signed-off-by: Jakub Kicinski

ptp: ptp_vmclock: remove dependency on CONFIG_ACPI

2026-02-03T02:06:01+00:00

Now that we added device tree support we can remove dependency on CONFIG_ACPI. Signed-off-by: David Woodhouse Signed-off-by: Babis Chalios Tested-by: Takahiro Itazuri Link: https://patch.msgid.link/20260130173704.12575-7-itazur@amazon.com Signed-off-by: Jakub Kicinski

ptp: ptp_vmclock: add 'VMCLOCK' to ACPI device match

2026-02-03T02:06:01+00:00

As we finalised the spec, we spotted that vmgenid actually says that the _HID is supposed to be hypervisor-specific. Although in the 13 years since the original vmgenid doc was published, nobody seems to have cared about using _HID to distinguish between implementations on different hypervisors, and we only ever use the _CID. For consistency, match the _CID of "VMCLOCK" too. Signed-off-by: David Woodhouse Signed-off-by: Babis Chalios Tested-by: Takahiro Itazuri Link: https://patch.msgid.link/20260130173704.12575-6-itazur@amazon.com Signed-off-by: Jakub Kicinski

ptp: ptp_vmclock: Add device tree support

2026-02-03T02:06:01+00:00

Add device tree support to the ptp_vmclock driver, allowing it to probe via device tree in addition to ACPI. Handle optional interrupt for clock disruption notifications, mirroring the ACPI notification behaviour. Although the interrupt is marked as 'optional' in the DT bindings, if the device *advertises* the VMCLOCK_FLAG_NOTIFICATION_ABSENT then it *should* have an interrupt. The driver will refuse to initialize if not. Signed-off-by: David Woodhouse Signed-off-by: Babis Chalios Signed-off-by: Takahiro Itazuri Tested-by: Takahiro Itazuri Link: https://patch.msgid.link/20260130173704.12575-5-itazur@amazon.com Signed-off-by: Jakub Kicinski

ptp: vmclock: support device notifications

2026-02-03T02:06:00+00:00

Add optional support for device notifications in VMClock. When supported, the hypervisor will send a device notification every time it updates the seq_count to a new even value. Moreover, add support for poll() in VMClock as a means to propagate this notification to user space. poll() will return a POLLIN event to listeners every time seq_count changes to a value different than the one last seen (since open() or last read()/pread()). This means that when poll() returns a POLLIN event, listeners need to use read() to observe what has changed and update the reader's view of seq_count. In other words, after a poll() returned, all subsequent calls to poll() will immediately return with a POLLIN event until the listener calls read(). The device advertises support for the notification mechanism by setting flag VMCLOCK_FLAG_NOTIFICATION_PRESENT in vmclock_abi flags field. If the flag is not present the driver won't setup the ACPI notification handler and poll() will always immediately return POLLHUP. Signed-off-by: Babis Chalios Signed-off-by: David Woodhouse Signed-off-by: Takahiro Itazuri Reviewed-by: David Woodhouse Tested-by: Takahiro Itazuri Link: https://patch.msgid.link/20260130173704.12575-3-itazur@amazon.com Signed-off-by: Jakub Kicinski

ptp: vmclock: Remove goto-based cleanup logic

2025-02-11T09:20:52+00:00

vmclock_probe() uses an "out:" label to return from the function on error. This indicates that some cleanup operation is necessary. However the label does not do anything as all resources are managed through devres, making the code slightly harder to read. Remove the label and just return directly. Signed-off-by: Thomas Weißschuh Acked-by: Richard Cochran Reviewed-by: David Woodhouse Signed-off-by: Paolo Abeni

ptp: vmclock: Clean up miscdev and ptp clock through devres

2025-02-11T09:20:52+00:00

Most resources owned by the vmclock device are managed through devres. Only the miscdev and ptp clock are managed manually. This makes the code slightly harder to understand than necessary. Switch them over to devres and remove the now unnecessary drvdata. Signed-off-by: Thomas Weißschuh Acked-by: Richard Cochran Reviewed-by: David Woodhouse Signed-off-by: Paolo Abeni

ptp: vmclock: Don't unregister misc device if it was not registered

2025-02-11T09:20:52+00:00

vmclock_remove() tries to detect the successful registration of the misc device based on the value of its minor value. However that check is incorrect if the misc device registration was not attempted in the first place. Always initialize the minor number, so the check works properly. Fixes: 205032724226 ("ptp: Add support for the AMZNC10C 'vmclock' device") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh Acked-by: Richard Cochran Reviewed-by: David Woodhouse Signed-off-by: Paolo Abeni