On Wed, Sep 22, 2021 at 12:10:41PM +0200, Ard Biesheuvel wrote: > On Tue, 21 Sept 2021 at 23:49, Emmanuel Gil Peyrot > <linkmauve@xxxxxxxxxxxx> wrote: > > > > This engine implements AES in CBC mode, using 128-bit keys only. It is > > present on both the Wii and the Wii U, and is apparently identical in > > both consoles. > > > > The hardware is capable of firing an interrupt when the operation is > > done, but this driver currently uses a busy loop, I’m not too sure > > whether it would be preferable to switch, nor how to achieve that. > > > > It also supports a mode where no operation is done, and thus could be > > used as a DMA copy engine, but I don’t know how to expose that to the > > kernel or whether it would even be useful. > > > > In my testing, on a Wii U, this driver reaches 80.7 MiB/s, while the > > aes-generic driver only reaches 30.9 MiB/s, so it is a quite welcome > > speedup. > > > > This driver was written based on reversed documentation, see: > > https://wiibrew.org/wiki/Hardware/AES > > > > Signed-off-by: Emmanuel Gil Peyrot <linkmauve@xxxxxxxxxxxx> > > Tested-by: Emmanuel Gil Peyrot <linkmauve@xxxxxxxxxxxx> # on Wii U > > This is redundant - everybody should test the code they submit. Indeed, except for the comment, as I haven’t been able to test on the Wii just yet and that’s kind of a call for doing exactly that. :) > > ... > > + /* TODO: figure out how to use interrupts here, this will probably > > + * lower throughput but let the CPU do other things while the AES > > + * engine is doing its work. */ > > So is it worthwhile like this? How much faster is it to use this > accelerator rather than the CPU? As I mentioned above, on my hardware it reaches 80.7 MiB/s using this busy loop instead of 30.9 MiB/s using aes-generic, measured using `cryptsetup benchmark --cipher=aes --key-size=128`. I expect the difference would be even more pronounced on the Wii, with its CPU being clocked lower. I will give a try at using the interrupt, but I fully expect a lower throughput alongside a lower CPU usage (for large requests). > > > + do { > > + status = ioread32be(base + AES_CTRL); > > + cpu_relax(); > > + } while ((status & AES_CTRL_EXEC) && --counter); > > + > > + /* Do we ever get called with dst ≠ src? If so we have to invalidate > > + * dst in addition to the earlier flush of src. */ > > + if (unlikely(dst != src)) { > > + for (i = 0; i < len; i += 32) > > + __asm__("dcbi 0, %0" : : "r" (dst + i)); > > + __asm__("sync" : : : "memory"); > > + } > > + > > + return counter ? 0 : 1; > > +} > > + > > +static void > > +nintendo_aes_crypt(const void *src, void *dst, u32 len, u8 *iv, int dir, > > + bool firstchunk) > > +{ > > + u32 flags = 0; > > + unsigned long iflags; > > + int ret; > > + > > + flags |= AES_CTRL_EXEC_INIT /* | AES_CTRL_IRQ */ | AES_CTRL_ENA; > > + > > + if (dir == AES_DIR_DECRYPT) > > + flags |= AES_CTRL_DEC; > > + > > + if (!firstchunk) > > + flags |= AES_CTRL_IV; > > + > > + /* Start the critical section */ > > + spin_lock_irqsave(&lock, iflags); > > + > > + if (firstchunk) > > + writefield(AES_IV, iv); > > + > > + ret = do_crypt(src, dst, len, flags); > > + BUG_ON(ret); > > + > > + spin_unlock_irqrestore(&lock, iflags); > > +} > > + > > +static int nintendo_setkey_skcipher(struct crypto_skcipher *tfm, const u8 *key, > > + unsigned int len) > > +{ > > + /* The hardware only supports AES-128 */ > > + if (len != AES_KEYSIZE_128) > > + return -EINVAL; > > + > > + writefield(AES_KEY, key); > > + return 0; > > +} > > + > > +static int nintendo_skcipher_crypt(struct skcipher_request *req, int dir) > > +{ > > + struct skcipher_walk walk; > > + unsigned int nbytes; > > + int err; > > + char ivbuf[AES_BLOCK_SIZE]; > > + unsigned int ivsize; > > + > > + bool firstchunk = true; > > + > > + /* Reset the engine */ > > + iowrite32be(0, base + AES_CTRL); > > + > > + err = skcipher_walk_virt(&walk, req, false); > > + ivsize = min(sizeof(ivbuf), walk.ivsize); > > + > > + while ((nbytes = walk.nbytes) != 0) { > > + unsigned int chunkbytes = round_down(nbytes, AES_BLOCK_SIZE); > > + unsigned int ret = nbytes % AES_BLOCK_SIZE; > > + > > + if (walk.total == chunkbytes && dir == AES_DIR_DECRYPT) { > > + /* If this is the last chunk and we're decrypting, take > > + * note of the IV (which is the last ciphertext block) > > + */ > > + memcpy(ivbuf, walk.src.virt.addr + walk.total - ivsize, > > + ivsize); > > + } > > + > > + nintendo_aes_crypt(walk.src.virt.addr, walk.dst.virt.addr, > > + chunkbytes, walk.iv, dir, firstchunk); > > + > > + if (walk.total == chunkbytes && dir == AES_DIR_ENCRYPT) { > > + /* If this is the last chunk and we're encrypting, take > > + * note of the IV (which is the last ciphertext block) > > + */ > > + memcpy(walk.iv, > > + walk.dst.virt.addr + walk.total - ivsize, > > + ivsize); > > + } else if (walk.total == chunkbytes && dir == AES_DIR_DECRYPT) { > > + memcpy(walk.iv, ivbuf, ivsize); > > + } > > + > > + err = skcipher_walk_done(&walk, ret); > > + firstchunk = false; > > + } > > + > > + return err; > > +} > > + > > +static int nintendo_cbc_encrypt(struct skcipher_request *req) > > +{ > > + return nintendo_skcipher_crypt(req, AES_DIR_ENCRYPT); > > +} > > + > > +static int nintendo_cbc_decrypt(struct skcipher_request *req) > > +{ > > + return nintendo_skcipher_crypt(req, AES_DIR_DECRYPT); > > +} > > + > > +static struct skcipher_alg nintendo_alg = { > > + .base.cra_name = "cbc(aes)", > > + .base.cra_driver_name = "cbc-aes-nintendo", > > + .base.cra_priority = 400, > > + .base.cra_flags = CRYPTO_ALG_KERN_DRIVER_ONLY, > > + .base.cra_blocksize = AES_BLOCK_SIZE, > > + .base.cra_alignmask = 15, > > + .base.cra_module = THIS_MODULE, > > + .setkey = nintendo_setkey_skcipher, > > + .encrypt = nintendo_cbc_encrypt, > > + .decrypt = nintendo_cbc_decrypt, > > + .min_keysize = AES_KEYSIZE_128, > > + .max_keysize = AES_KEYSIZE_128, > > + .ivsize = AES_BLOCK_SIZE, > > +}; > > + > > +static int nintendo_aes_remove(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + > > + crypto_unregister_skcipher(&nintendo_alg); > > + devm_iounmap(dev, base); > > + base = NULL; > > + > > + return 0; > > +} > > + > > +static int nintendo_aes_probe(struct platform_device *pdev) > > +{ > > + struct device *dev = &pdev->dev; > > + struct resource *res; > > + int ret; > > + > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + base = devm_ioremap_resource(dev, res); > > + if (IS_ERR(base)) > > + return PTR_ERR(base); > > + > > + spin_lock_init(&lock); > > + > > + ret = crypto_register_skcipher(&nintendo_alg); > > + if (ret) > > + goto eiomap; > > + > > + dev_notice(dev, "Nintendo Wii and Wii U AES engine enabled\n"); > > + return 0; > > + > > + eiomap: > > + devm_iounmap(dev, base); > > + > > + dev_err(dev, "Nintendo Wii and Wii U AES initialization failed\n"); > > + return ret; > > +} > > + > > +static const struct of_device_id nintendo_aes_of_match[] = { > > + { .compatible = "nintendo,hollywood-aes", }, > > + { .compatible = "nintendo,latte-aes", }, > > + {/* sentinel */}, > > +}; > > +MODULE_DEVICE_TABLE(of, nintendo_aes_of_match); > > + > > +static struct platform_driver nintendo_aes_driver = { > > + .driver = { > > + .name = "nintendo-aes", > > + .of_match_table = nintendo_aes_of_match, > > + }, > > + .probe = nintendo_aes_probe, > > + .remove = nintendo_aes_remove, > > +}; > > + > > +module_platform_driver(nintendo_aes_driver); > > + > > +MODULE_AUTHOR("Emmanuel Gil Peyrot <linkmauve@xxxxxxxxxxxx>"); > > +MODULE_DESCRIPTION("Nintendo Wii and Wii U Hardware AES driver"); > > +MODULE_LICENSE("GPL"); > > -- > > 2.33.0 > > -- Emmanuel Gil Peyrot
Attachment:
signature.asc
Description: PGP signature
