libdevinfo: Avoid false positives for the root0 sentinel value
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Authored by jhb on Jan 25 2025, 2:42 AM.

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imp
jrtc27

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rG7554746c43c5: libdevinfo: Avoid false positives for the root0 sentinel value

Summary

Previously, a NULL pointer value was used to request the root0 device
at the top of the device tree. However, this meant that resource
ranges from a rman with a NULL device pointer were annotated as being
owned by root0 instead of being unowned. Switch to a different value
for root0's sentinel to avoid the clash.

Since this is an ABI change, bump the SHLIB_MAJOR for libdevinfo to 7.

Reported by: jrtc27

Diff Detail

Repository

rG FreeBSD src repository

Lint

Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

jhb requested review of this revision.Jan 25 2025, 2:42 AM

jhb created this revision.

Harbormaster completed remote builds in B62017: Diff 149947.Jan 25 2025, 2:42 AM

Fix looking up root0

Harbormaster completed remote builds in B62018: Diff 149948.Jan 25 2025, 3:43 AM

Before in a VM:

# devinfo -u
Interrupt request lines:
    0x0 (attimer0)
    0x1 (atkbdc0)
    0x3 (uart3)
    0x3 (uart1)
    0x4 (uart2)
    0x4 (uart0)
    0x5-0x7 (root0)
    0x8 (atrtc0)
    0x9 (acpi0)
    0xa-0xb (root0)
    0xc (psm0)
    0xd-0x1f (root0)
    0x20 (hpet0)
    0x21 (hpet0)
    0x22 (hpet0)
    0x23 (hpet0)
    0x24 (hpet0)
    0x25 (hpet0)
    0x26 (hpet0)
    0x27 (hpet0)
    0x28 (virtio_pci0)
    0x29 (virtio_pci0)
    0x2a (virtio_pci1)
    0x2b (virtio_pci1)
    0x2c (virtio_pci1)
    0x2d (nvme0)
    0x2e (nvme0)
    0x2f (nvme0)
    0x30 (nvme0)
    0x31 (nvme0)
    0x32 (nvme0)
    0x33 (nvme0)
    0x34 (nvme0)
    0x35 (nvme0)
    0x36 (nvme0)
    0x37 (nvme0)
    0x38 (nvme0)
    0x39 (nvme0)
    0x3a (nvme0)
    0x3b (nvme0)
    0x3c (nvme0)
    0x3d (nvme0)
DMA request lines:
    0-7 (root0)
I/O ports:
    0x0-0x1f (root0)
    0x20-0x21 ----
    0x22-0x3f (root0)
    0x40-0x43 (attimer0)
    0x44-0x5f (root0)
    0x60 (atkbdc0)
    0x61 (acpi0)
    0x62-0x63 (root0)
    0x64 (atkbdc0)
    0x65-0x6f (root0)
    0x70-0x71 (atrtc0)
    0x72-0x77 (acpi0)
    0x78-0x83 (root0)
    0x84 (acpi0)
    0x85-0x9f (root0)
    0xa0-0xa1 ----
    0xa2-0xb1 (root0)
    0xb2 (acpi0)
    0xb3-0x2e7 (root0)
    0x2e8-0x2ef (uart3)
    0x2f0-0x2f7 (root0)
    0x2f8-0x2ff (uart1)
    0x300-0x3af (root0)
    0x3b0-0x3bb (vga0)
    0x3bc-0x3e7 (root0)
    0x3e8-0x3ef (uart2)
    0x3f0-0x3f7 (root0)
    0x3f8-0x3ff (uart0)
    0x400-0x407 (acpi0)
    0x408-0x40b (acpi_timer0)
    0x40c-0x4cf (root0)
    0x4d0-0x4d1 (acpi0)
    0x4d2-0xcf7 (root0)
    0xcf8-0xcff (pcib0)
    0xd00-0x1fff (root0)
    0x2000-0x207f (virtio_pci0)
    0x2080-0x20bf (virtio_pci1)
    0x20c0-0x20df (virtio_pci2)
    0x20e0-0xffff (root0)
I/O memory addresses:
    0x0-0x9ffff (ram0)
    0xa0000-0xaffff (root0)
    0xb0000-0xb7fff (vga0)
    0xb8000-0xfffff (root0)
    0x100000-0xbfffffff (ram0)
    0xc0000000-0xc0003fff (nvme0)
    0xc0004000-0xc0005fff (virtio_pci0)
    0xc0006000-0xc0007fff (virtio_pci1)
    0xc0008000-0xc0009fff (virtio_pci2)
    0xc000a000-0xc000bfff (nvme0)
    0xc000c000-0xdfffffff (root0)
    0xe0000000-0xefffffff (acpi0)
    0xf0000000-0xfebfffff (root0)
    0xfec00000-0xfec0001f (apic0)
    0xfec00020-0xfecfffff (root0)
    0xfed00000-0xfed003ff (hpet0)
    0xfed00400-0xfedfffff (root0)
    0xfee00000-0xfee0053f (apic0)
    0xfee00540-0xffffffff (root0)
    0x100000000-0x43fffffff (ram0)
    0x440000000-0xffffffffffff (root0)
ACPI I/O ports:
    0x61 (root0)
    0x72-0x77 (root0)
    0x84 (root0)
    0xb2 (root0)
    0x400-0x407 (root0)
    0x4d0-0x4d1 (root0)
ACPI I/O memory addresses:
    0xe0000000-0xefffffff (root0)
PCI domain 0 bus numbers:
    0 (pci0)
    1-255 (root0)

after:

# devinfo -u
Interrupt request lines:
    0x0 (attimer0)
    0x1 (atkbdc0)
    0x3 (uart3)
    0x3 (uart1)
    0x4 (uart2)
    0x4 (uart0)
    0x5-0x7 ----
    0x8 (atrtc0)
    0x9 (acpi0)
    0xa-0xb ----
    0xc (psm0)
    0xd-0x1f ----
    0x20 (hpet0)
    0x21 (hpet0)
    0x22 (hpet0)
    0x23 (hpet0)
    0x24 (hpet0)
    0x25 (hpet0)
    0x26 (hpet0)
    0x27 (hpet0)
    0x28 (virtio_pci0)
    0x29 (virtio_pci0)
    0x2a (virtio_pci1)
    0x2b (virtio_pci1)
    0x2c (virtio_pci1)
    0x2d (nvme0)
    0x2e (nvme0)
    0x2f (nvme0)
    0x30 (nvme0)
    0x31 (nvme0)
    0x32 (nvme0)
    0x33 (nvme0)
    0x34 (nvme0)
    0x35 (nvme0)
    0x36 (nvme0)
    0x37 (nvme0)
    0x38 (nvme0)
    0x39 (nvme0)
    0x3a (nvme0)
    0x3b (nvme0)
    0x3c (nvme0)
    0x3d (nvme0)
DMA request lines:
    0-7 ----
I/O ports:
    0x0-0x1f ----
    0x20-0x21 ----
    0x22-0x3f ----
    0x40-0x43 (attimer0)
    0x44-0x5f ----
    0x60 (atkbdc0)
    0x61 (acpi0)
    0x62-0x63 ----
    0x64 (atkbdc0)
    0x65-0x6f ----
    0x70-0x71 (atrtc0)
    0x72-0x77 (acpi0)
    0x78-0x83 ----
    0x84 (acpi0)
    0x85-0x9f ----
    0xa0-0xa1 ----
    0xa2-0xb1 ----
    0xb2 (acpi0)
    0xb3-0x2e7 ----
    0x2e8-0x2ef (uart3)
    0x2f0-0x2f7 ----
    0x2f8-0x2ff (uart1)
    0x300-0x3af ----
    0x3b0-0x3bb (vga0)
    0x3bc-0x3e7 ----
    0x3e8-0x3ef (uart2)
    0x3f0-0x3f7 ----
    0x3f8-0x3ff (uart0)
    0x400-0x407 (acpi0)
    0x408-0x40b (acpi_timer0)
    0x40c-0x4cf ----
    0x4d0-0x4d1 (acpi0)
    0x4d2-0xcf7 ----
    0xcf8-0xcff (pcib0)
    0xd00-0x1fff ----
    0x2000-0x207f (virtio_pci0)
    0x2080-0x20bf (virtio_pci1)
    0x20c0-0x20df (virtio_pci2)
    0x20e0-0xffff ----
I/O memory addresses:
    0x0-0x9ffff (ram0)
    0xa0000-0xaffff ----
    0xb0000-0xb7fff (vga0)
    0xb8000-0xfffff ----
    0x100000-0xbfffffff (ram0)
    0xc0000000-0xc0003fff (nvme0)
    0xc0004000-0xc0005fff (virtio_pci0)
    0xc0006000-0xc0007fff (virtio_pci1)
    0xc0008000-0xc0009fff (virtio_pci2)
    0xc000a000-0xc000bfff (nvme0)
    0xc000c000-0xdfffffff ----
    0xe0000000-0xefffffff (acpi0)
    0xf0000000-0xfebfffff ----
    0xfec00000-0xfec0001f (apic0)
    0xfec00020-0xfecfffff ----
    0xfed00000-0xfed003ff (hpet0)
    0xfed00400-0xfedfffff ----
    0xfee00000-0xfee0053f (apic0)
    0xfee00540-0xffffffff ----
    0x100000000-0x43fffffff (ram0)
    0x440000000-0xffffffffffff ----
ACPI I/O ports:
    0x61 ----
    0x72-0x77 ----
    0x84 ----
    0xb2 ----
    0x400-0x407 ----
    0x4d0-0x4d1 ----
ACPI I/O memory addresses:
    0xe0000000-0xefffffff ----
PCI domain 0 bus numbers:
    0 (pci0)
    1-255 ----

jhb added a child revision: D48676: devinfo: Distinguish resources owned by unnamed devices from free resources.Jan 25 2025, 3:52 AM

imp accepted this revision.Jan 26 2025, 3:53 AM

imp added inline comments.

lib/libdevinfo/devinfo.h
37	why 1?

This revision is now accepted and ready to land.Jan 26 2025, 3:53 AM

jhb added inline comments.Jan 27 2025, 2:27 PM

lib/libdevinfo/devinfo.h
37	I just need some value that isn't a valid kernel pointer. The sysctls are returning pointers to device_t objects as the handles for devices. In some cases a NULL pointer can be returned (such as for "free" address ranges) and so 0 needs to be avoided. It seems unlikely that a device_t pointer in the kernel will ever be `(void *)1`. -1 is probably also safe which is the other option I considered.

One could conceivably imagine the handles being small positive integers (nexus0 is 1, and so on) rather than using kernel addresses, so -1 seems more flexible IMO, and is generally a clear sentinel.

Switch to -1

This revision now requires review to proceed.Jan 28 2025, 8:34 PM

Harbormaster completed remote builds in B62084: Diff 150082.Jan 28 2025, 8:34 PM

This revision was not accepted when it landed; it landed in state Needs Review.Jan 29 2025, 4:32 PM

Closed by commit rG7554746c43c5: libdevinfo: Avoid false positives for the root0 sentinel value (authored by jhb). · Explain Why

This revision was automatically updated to reflect the committed changes.

jhb added a commit: rG7554746c43c5: libdevinfo: Avoid false positives for the root0 sentinel value.