diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/filesystems/fscrypt.rst | 37 | ||||
| -rw-r--r-- | Documentation/firmware-guide/acpi/i2c-muxes.rst | 8 |
2 files changed, 19 insertions, 26 deletions
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 04eaab01314b..b07368e949ae 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -141,9 +141,8 @@ However, these ioctls have some limitations: CONFIG_PAGE_POISONING=y in your kernel config and add page_poison=1 to your kernel command line. However, this has a performance cost. -- Secret keys might still exist in CPU registers, in crypto - accelerator hardware (if used by the crypto API to implement any of - the algorithms), or in other places not explicitly considered here. +- Secret keys might still exist in CPU registers or in other places + not explicitly considered here. Limitations of v1 policies ~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -378,9 +377,12 @@ the work is done by XChaCha12, which is much faster than AES when AES acceleration is unavailable. For more information about Adiantum, see `the Adiantum paper <https://eprint.iacr.org/2018/720.pdf>`_. -The (AES-128-CBC-ESSIV, AES-128-CBC-CTS) pair exists only to support -systems whose only form of AES acceleration is an off-CPU crypto -accelerator such as CAAM or CESA that does not support XTS. +The (AES-128-CBC-ESSIV, AES-128-CBC-CTS) pair was added to try to +provide a more efficient option for systems that lack AES instructions +in the CPU but do have a non-inline crypto engine such as CAAM or CESA +that supports AES-CBC (and not AES-XTS). This is deprecated. It has +been shown that just doing AES on the CPU is actually faster. +Moreover, Adiantum is faster still and is recommended on such systems. The remaining mode pairs are the "national pride ciphers": @@ -1289,22 +1291,13 @@ this by validating all top-level encryption policies prior to access. Inline encryption support ========================= -By default, fscrypt uses the kernel crypto API for all cryptographic -operations (other than HKDF, which fscrypt partially implements -itself). The kernel crypto API supports hardware crypto accelerators, -but only ones that work in the traditional way where all inputs and -outputs (e.g. plaintexts and ciphertexts) are in memory. fscrypt can -take advantage of such hardware, but the traditional acceleration -model isn't particularly efficient and fscrypt hasn't been optimized -for it. - -Instead, many newer systems (especially mobile SoCs) have *inline -encryption hardware* that can encrypt/decrypt data while it is on its -way to/from the storage device. Linux supports inline encryption -through a set of extensions to the block layer called *blk-crypto*. -blk-crypto allows filesystems to attach encryption contexts to bios -(I/O requests) to specify how the data will be encrypted or decrypted -in-line. For more information about blk-crypto, see +Many newer systems (especially mobile SoCs) have *inline encryption +hardware* that can encrypt/decrypt data while it is on its way to/from +the storage device. Linux supports inline encryption through a set of +extensions to the block layer called *blk-crypto*. blk-crypto allows +filesystems to attach encryption contexts to bios (I/O requests) to +specify how the data will be encrypted or decrypted in-line. For more +information about blk-crypto, see :ref:`Documentation/block/inline-encryption.rst <inline_encryption>`. On supported filesystems (currently ext4 and f2fs), fscrypt can use diff --git a/Documentation/firmware-guide/acpi/i2c-muxes.rst b/Documentation/firmware-guide/acpi/i2c-muxes.rst index 3a8997ccd7c4..f366539acd79 100644 --- a/Documentation/firmware-guide/acpi/i2c-muxes.rst +++ b/Documentation/firmware-guide/acpi/i2c-muxes.rst @@ -14,7 +14,7 @@ Consider this topology:: | | | 0x70 |--CH01--> i2c client B (0x50) +------+ +------+ -which corresponds to the following ASL:: +which corresponds to the following ASL (in the scope of \_SB):: Device (SMB1) { @@ -24,7 +24,7 @@ which corresponds to the following ASL:: Name (_HID, ...) Name (_CRS, ResourceTemplate () { I2cSerialBus (0x70, ControllerInitiated, I2C_SPEED, - AddressingMode7Bit, "^SMB1", 0x00, + AddressingMode7Bit, "\\_SB.SMB1", 0x00, ResourceConsumer,,) } @@ -37,7 +37,7 @@ which corresponds to the following ASL:: Name (_HID, ...) Name (_CRS, ResourceTemplate () { I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED, - AddressingMode7Bit, "^CH00", 0x00, + AddressingMode7Bit, "\\_SB.SMB1.CH00", 0x00, ResourceConsumer,,) } } @@ -52,7 +52,7 @@ which corresponds to the following ASL:: Name (_HID, ...) Name (_CRS, ResourceTemplate () { I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED, - AddressingMode7Bit, "^CH01", 0x00, + AddressingMode7Bit, "\\_SB.SMB1.CH01", 0x00, ResourceConsumer,,) } } |