kernel maps only one page of FDT. When FDT is more than one page in size, data TLB miss occurs on memmove()
when FDT is moved to kernel storage (sys/powerpc/booke/booke_machdep.c, booke_init())
Details
Details
- Reviewers
jhibbits - Commits
- rS304727: Fix system hang when large FDT is in use
- Build kernel, create uImage
mkimage -A ppc -O linux -e 0x4001000 -a 0x3ffffc0 -C none -d /tftpboot/fbsd /tftpboot/fbsd.uImage
- Boot uImage on the QorIQ system
> tftpboot 0x3ffffc0 k1
Using FM1@DTSEC3 device
TFTP from server 192.168.2.23; our IP address is 192.168.2.22
Filename 'k1'.
Load address: 0x3ffffc0
Loading: #############
- ############# ############# ############# ############# ############# ############# ############# ##############
3.1 MiB/s
done
Bytes transferred = 9380388 (8f2224 hex)
- Boot the image, ensure that kernel successfully reaches mi_startup() (you shall see greeting
when it does)
Bytes transferred = 9380388 (8f2224 hex)
> bootm 0x3ffffc0 - 0xec800000
WARNING: adjusting available memory to 30000000
Booting kernel from Legacy Image at 03ffffc0 ...
Image Name:
Image Type: PowerPC Linux Kernel Image (uncompressed)
Data Size: 9380324 Bytes = 8.9 MiB
Load Address: 03ffffc0
Entry Point: 04001000
Verifying Checksum ... OK
Flattened Device Tree blob at ec800000
Booting using the fdt blob at 0xec800000
XIP Kernel Image ... OK
Loading Device Tree to 03fe0000, end 03fff10b ... OK
HELLO FROM t2080 FREEBSD!!
Copyright (c) 1992-2016 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 12.0-CURRENT #40 9d6a66c(master)-dirty: Sun Aug 21 12:15:46 PDT 2016
root@int0dh-home:/usr/obj/powerpc.powerpc/usr/home/int0dh/WORK/freebsd.original/sys/AMIGAX5000 powerpc
gcc version 4.2.1 20070831 patched [FreeBSD]
WARNING: WITNESS option enabled, expect reduced performance.
...
Diff Detail
Diff Detail
- Repository
- rS FreeBSD src repository - subversion
- Lint
Lint Skipped - Unit
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Event Timeline
Comment Actions
Overall, good work. Just a couple nits and it'll be fine. This should definitely fix the hang problem I've seen booting from ubldr on one of my boards, so I'm excited about it.
| sys/powerpc/booke/pmap.c | ||
|---|---|---|
| 3416 | ||
| 3431 | This will only work right if the mapping completely encloses the region, it won't work if the region spans multiple TLB mappings, which is possible to do in pmap_early_io_map(). Since it's only used in one location right now, I guess it's okay, but just add a comment here that it should be fixed in the future. | |
Comment Actions
Looks good, I'll see if I can commit it tonight.
I put a few minutes of thought into the pmap_early_io_unmap() problem, and I think it'll be pretty easy to address, but it'll need either a new function (good idea) or some inline asm, to search for each TLB entry by VA. It's more complicated, and not needed right now, but something to think about for later on.