Rust for linux pdev rng v2 #16
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Since usage of PointerWrapper is not limited only to file operations, move it out from file_operations.rs to a more suitable place, types.rs. Fixes torvalds#144 Signed-off-by: Sumera Priyadarsini <[email protected]>
Proof-of-concept of a `bcm2835-rng` Rust driver. This is the hardware
random-number generator present on Raspberry Pi Zero(W), Classic,
Two, and Three. It's a convenient starting point because:
- it's ubiquitous: a Pi Zero can be purchased for $10
- it has QEMU Support (-M raspi2)
- it's very simple: just 0x10 bytes of register space
The hwrng is exposed as a Rust `miscdev` named `rust_hwrng`. Reading
its devnode will produce up to 4 random bytes at a time:
pi@raspberrypi:~$ hexdump -C /dev/rust_hwrng
00000000 ef 9c 19 8a |....|
00000004
Tested on a real Raspberry Pi Zero-W, and QEMU (-M raspi2).
Consider this to be a "pencil outline": most of the new Rust abstractions
I've introduced here are clunky, inelegant and incomplete - my Rust is very
poor. But I'm sure that collective wisdom can improve them. The `unsafe`
sections need careful review too.
Rust abstractions/infrastructure were introduced for the following kernel concepts:
- `struct platform_device` / `struct platform_driver`
- per-device driver data
- `struct regmap`
How to run on QEMU
==================
Download a Raspbian image. I used `2021-03-04-raspios-buster-armhf-lite.img`.
It will consist of two partitions. Discover their offsets using:
```sh
$ fdisk -l 2021-03-04-raspios-buster-armhf-lite.img
Device Boot Start End Sectors Size Id Type
2021-03-04-raspios-buster-armhf-lite.img1 8192 532479 524288 256M c W95 FAT32 (LBA)
2021-03-04-raspios-buster-armhf-lite.img2 532480 3645439 3112960 1.5G 83 Linux
```
Mount the second partition on your PC: (note how the offset is multiplied by 512)
```sh
$ mount -o loop,offset=$((512*532480)) 2021-03-04-raspios-buster-armhf-lite.img /mnt
Comment out everything in /etc/ld.so.preload - otherwise the Raspbian rootfs cannot support
a mainline kernel:
$ vi /etc/ld.so.preload # comment everything out
$ umount /mnt
```
Build the kernel for arm 32-bit:
```sh
$ make bcm2835_defconfig # defconfig modded so `bcm2835-rng` binds to Rust
$ make zImage dtbs modules
```
Start QEMU:
```sh
# to boot mainline, make sure that /etc/ld.so.preload is commented out
# in the Raspbian image.
qemu-system-arm \
-M raspi2 \
-append "rw earlyprintk loglevel=8 console=ttyAMA0,115200 dwc_otg.lpm_enable=0 root=/dev/mmcblk0p2 rootwait" \
-cpu arm1176 \
-dtb bcm2836-rpi-2-b.dts \
-hda ./2021-03-04-raspios-buster-armhf-lite.img \
-kernel zImage \
-m 1G \
-smp 4 \
-nographic \
;
```
How to run on a Raspberry Pi Zero(W)
====================================
Follow the instructions for QEMU above. Deploy the Raspbian image to SD card.
Copy zImage and bcm2835-rpi-zero-w.dtb to Raspbian's first (boot) partition:
```
zImage -> boot partition: kernel.img
bcm2835-rpi-zero-w.dtb -> boot partition: bcm2708-rpi-0-w.dtb
```
If you'd like wifi to keep working, also copy the kernel modules you built to
Raspbian's second partition:
```sh
$ make modules_install INSTALL_MOD_PATH=<somewhere>
$ cp -rfa <somewhere> <Raspbian Partition> # should end up in /lib/modules/5.12.0-rc4+/
```
Signed-off-by: Sven Van Asbroeck <[email protected]>
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There is a panic in socket ioctl cmd SIOCGSKNS when NET_NS is not enabled. The reason is that nsfs tries to access ns->ops but the proc_ns_operations is not implemented in this case. [7.670023] Unable to handle kernel NULL pointer dereference at virtual address 00000010 [7.670268] pgd = 32b54000 [7.670544] [00000010] *pgd=00000000 [7.671861] Internal error: Oops: 5 [#1] SMP ARM [7.672315] Modules linked in: [7.672918] CPU: 0 PID: 1 Comm: systemd Not tainted 5.13.0-rc3-00375-g6799d4f2da49 #16 [7.673309] Hardware name: Generic DT based system [7.673642] PC is at nsfs_evict+0x24/0x30 [7.674486] LR is at clear_inode+0x20/0x9c The same to tun SIOCGSKNS command. To fix this problem, we make get_net_ns() return -EINVAL when NET_NS is disabled. Meanwhile move it to right place net/core/net_namespace.c. Signed-off-by: Changbin Du <[email protected]> Fixes: c62cce2 ("net: add an ioctl to get a socket network namespace") Cc: Cong Wang <[email protected]> Cc: Jakub Kicinski <[email protected]> Cc: David Laight <[email protected]> Cc: Christian Brauner <[email protected]> Suggested-by: Jakub Kicinski <[email protected]> Acked-by: Christian Brauner <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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