1: # Jonathan Kollasch
2:
3: ## [[!template id=man name="ddb" section="4"]] tips
4:
5: ### locating a softc
6: This locates a device's softc using it's `cfdriver_t` (e.g. `&mainbus_cd`, `&cpu_cd`) and its "device unit" (e.g. the `0` in `mainbus0`).
7:
8: db{0}> call device_lookup_private(ohci_cd, 0)
9: 0xffff800045fb2008
10:
11: ### locating structure members
12: This uses [[!template id=man name="gdb" section="1"]] and a kernel with debugging symbols to find the offset to a element in a structure.
13:
14: $ gdb netbsd.gdb
15: ...
16: (gdb) print &((struct ohci_softc *)0)->iot
17: $3 = (bus_space_tag_t *) 0x478
18: (gdb) print &((struct ohci_softc *)0)->ioh
19: $4 = (bus_space_handle_t *) 0x480
20:
21: ### peeking at mapped registers
22:
23: db{0}> call bus_space_read_4(*(ffff800045fb2008+478), *(ffff800045fb2008+480), 0)
24: 0x110
25:
26: ## Unfinished Projects
27:
28: ### x86 UEFI kernel loader
29: Building this for x64 UEFI requires the `ms_abi` function attribute introduced in GCC 4.4 or so.
30: This project uses Intel UEFI headers and some existing FreeBSD work.
31: Needs more work and cleanup, also toolchain updates.
32: Work has been done using the OVMF BIOS images for Qemu.
33:
34: ### bcm47xx for evbmips
35: Boots multiuser on NFS root, needs more work and cleanup.
36: This project is on hold until there's a miniature userland that fits in 4-8MiB flash storage devices, on a flash-oriented file system.
37: [[!template id=man name="bce" section="4"]] and [[!template id=man name="bwi" section="4"]] would need refactoring to be bus-independent.
38:
39: ### Memory-mapped PCI config access on x86
40: Needs cleanup, and maybe some more validation of MCFG tables.
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