diff options
Diffstat (limited to 'Documentation/crypto')
| -rw-r--r-- | Documentation/crypto/api-intro.rst (renamed from Documentation/crypto/api-intro.txt) | 186 | ||||
| -rw-r--r-- | Documentation/crypto/asymmetric-keys.rst (renamed from Documentation/crypto/asymmetric-keys.txt) | 91 | ||||
| -rw-r--r-- | Documentation/crypto/async-tx-api.rst (renamed from Documentation/crypto/async-tx-api.txt) | 255 | ||||
| -rw-r--r-- | Documentation/crypto/descore-readme.rst (renamed from Documentation/crypto/descore-readme.txt) | 152 | ||||
| -rw-r--r-- | Documentation/crypto/index.rst | 5 |
5 files changed, 404 insertions, 285 deletions
diff --git a/Documentation/crypto/api-intro.txt b/Documentation/crypto/api-intro.rst index 40137f93e04f..15201be0b811 100644 --- a/Documentation/crypto/api-intro.txt +++ b/Documentation/crypto/api-intro.rst @@ -1,7 +1,11 @@ +.. SPDX-License-Identifier: GPL-2.0 - Scatterlist Cryptographic API - -INTRODUCTION +============================= +Scatterlist Cryptographic API +============================= + +Introduction +============ The Scatterlist Crypto API takes page vectors (scatterlists) as arguments, and works directly on pages. In some cases (e.g. ECB @@ -13,22 +17,23 @@ so that processing can be applied to paged skb's without the need for linearization. -DETAILS +Details +======= At the lowest level are algorithms, which register dynamically with the API. 'Transforms' are user-instantiated objects, which maintain state, handle all -of the implementation logic (e.g. manipulating page vectors) and provide an -abstraction to the underlying algorithms. However, at the user +of the implementation logic (e.g. manipulating page vectors) and provide an +abstraction to the underlying algorithms. However, at the user level they are very simple. -Conceptually, the API layering looks like this: +Conceptually, the API layering looks like this:: [transform api] (user interface) [transform ops] (per-type logic glue e.g. cipher.c, compress.c) [algorithm api] (for registering algorithms) - + The idea is to make the user interface and algorithm registration API very simple, while hiding the core logic from both. Many good ideas from existing APIs such as Cryptoapi and Nettle have been adapted for this. @@ -44,21 +49,21 @@ one block while the former can operate on an arbitrary amount of data, subject to block size requirements (i.e., non-stream ciphers can only process multiples of blocks). -Here's an example of how to use the API: +Here's an example of how to use the API:: #include <crypto/hash.h> #include <linux/err.h> #include <linux/scatterlist.h> - + struct scatterlist sg[2]; char result[128]; struct crypto_ahash *tfm; struct ahash_request *req; - + tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) fail(); - + /* ... set up the scatterlists ... */ req = ahash_request_alloc(tfm, GFP_ATOMIC); @@ -67,18 +72,19 @@ Here's an example of how to use the API: ahash_request_set_callback(req, 0, NULL, NULL); ahash_request_set_crypt(req, sg, result, 2); - + if (crypto_ahash_digest(req)) fail(); ahash_request_free(req); crypto_free_ahash(tfm); - + Many real examples are available in the regression test module (tcrypt.c). -DEVELOPER NOTES +Developer Notes +=============== Transforms may only be allocated in user context, and cryptographic methods may only be called from softirq and user contexts. For @@ -91,7 +97,8 @@ size (typically 8 bytes). This prevents having to do any copying across non-aligned page fragment boundaries. -ADDING NEW ALGORITHMS +Adding New Algorithms +===================== When submitting a new algorithm for inclusion, a mandatory requirement is that at least a few test vectors from known sources (preferably @@ -119,132 +126,137 @@ Also check the TODO list at the web site listed below to see what people might already be working on. -BUGS +Bugs +==== Send bug reports to: -linux-crypto@vger.kernel.org -Cc: Herbert Xu <herbert@gondor.apana.org.au>, + linux-crypto@vger.kernel.org + +Cc: + Herbert Xu <herbert@gondor.apana.org.au>, David S. Miller <davem@redhat.com> -FURTHER INFORMATION +Further Information +=================== For further patches and various updates, including the current TODO list, see: http://gondor.apana.org.au/~herbert/crypto/ -AUTHORS +Authors +======= -James Morris -David S. Miller -Herbert Xu +- James Morris +- David S. Miller +- Herbert Xu -CREDITS +Credits +======= The following people provided invaluable feedback during the development of the API: - Alexey Kuznetzov - Rusty Russell - Herbert Valerio Riedel - Jeff Garzik - Michael Richardson - Andrew Morton - Ingo Oeser - Christoph Hellwig + - Alexey Kuznetzov + - Rusty Russell + - Herbert Valerio Riedel + - Jeff Garzik + - Michael Richardson + - Andrew Morton + - Ingo Oeser + - Christoph Hellwig Portions of this API were derived from the following projects: - + Kerneli Cryptoapi (http://www.kerneli.org/) - Alexander Kjeldaas - Herbert Valerio Riedel - Kyle McMartin - Jean-Luc Cooke - David Bryson - Clemens Fruhwirth - Tobias Ringstrom - Harald Welte + - Alexander Kjeldaas + - Herbert Valerio Riedel + - Kyle McMartin + - Jean-Luc Cooke + - David Bryson + - Clemens Fruhwirth + - Tobias Ringstrom + - Harald Welte and; - + Nettle (https://www.lysator.liu.se/~nisse/nettle/) - Niels Möller + - Niels Möller Original developers of the crypto algorithms: - Dana L. How (DES) - Andrew Tridgell and Steve French (MD4) - Colin Plumb (MD5) - Steve Reid (SHA1) - Jean-Luc Cooke (SHA256, SHA384, SHA512) - Kazunori Miyazawa / USAGI (HMAC) - Matthew Skala (Twofish) - Dag Arne Osvik (Serpent) - Brian Gladman (AES) - Kartikey Mahendra Bhatt (CAST6) - Jon Oberheide (ARC4) - Jouni Malinen (Michael MIC) - NTT(Nippon Telegraph and Telephone Corporation) (Camellia) + - Dana L. How (DES) + - Andrew Tridgell and Steve French (MD4) + - Colin Plumb (MD5) + - Steve Reid (SHA1) + - Jean-Luc Cooke (SHA256, SHA384, SHA512) + - Kazunori Miyazawa / USAGI (HMAC) + - Matthew Skala (Twofish) + - Dag Arne Osvik (Serpent) + - Brian Gladman (AES) + - Kartikey Mahendra Bhatt (CAST6) + - Jon Oberheide (ARC4) + - Jouni Malinen (Michael MIC) + - NTT(Nippon Telegraph and Telephone Corporation) (Camellia) SHA1 algorithm contributors: - Jean-Francois Dive - + - Jean-Francois Dive + DES algorithm contributors: - Raimar Falke - Gisle Sælensminde - Niels Möller + - Raimar Falke + - Gisle Sælensminde + - Niels Möller Blowfish algorithm contributors: - Herbert Valerio Riedel - Kyle McMartin + - Herbert Valerio Riedel + - Kyle McMartin Twofish algorithm contributors: - Werner Koch - Marc Mutz + - Werner Koch + - Marc Mutz SHA256/384/512 algorithm contributors: - Andrew McDonald - Kyle McMartin - Herbert Valerio Riedel - + - Andrew McDonald + - Kyle McMartin + - Herbert Valerio Riedel + AES algorithm contributors: - Alexander Kjeldaas - Herbert Valerio Riedel - Kyle McMartin - Adam J. Richter - Fruhwirth Clemens (i586) - Linus Torvalds (i586) + - Alexander Kjeldaas + - Herbert Valerio Riedel + - Kyle McMartin + - Adam J. Richter + - Fruhwirth Clemens (i586) + - Linus Torvalds (i586) CAST5 algorithm contributors: - Kartikey Mahendra Bhatt (original developers unknown, FSF copyright). + - Kartikey Mahendra Bhatt (original developers unknown, FSF copyright). TEA/XTEA algorithm contributors: - Aaron Grothe - Michael Ringe + - Aaron Grothe + - Michael Ringe Khazad algorithm contributors: - Aaron Grothe + - Aaron Grothe Whirlpool algorithm contributors: - Aaron Grothe - Jean-Luc Cooke + - Aaron Grothe + - Jean-Luc Cooke Anubis algorithm contributors: - Aaron Grothe + - Aaron Grothe Tiger algorithm contributors: - Aaron Grothe + - Aaron Grothe VIA PadLock contributors: - Michal Ludvig + - Michal Ludvig Camellia algorithm contributors: - NTT(Nippon Telegraph and Telephone Corporation) (Camellia) + - NTT(Nippon Telegraph and Telephone Corporation) (Camellia) Generic scatterwalk code by Adam J. Richter <adam@yggdrasil.com> Please send any credits updates or corrections to: Herbert Xu <herbert@gondor.apana.org.au> - diff --git a/Documentation/crypto/asymmetric-keys.txt b/Documentation/crypto/asymmetric-keys.rst index 8763866b11cf..349f44a29392 100644 --- a/Documentation/crypto/asymmetric-keys.txt +++ b/Documentation/crypto/asymmetric-keys.rst @@ -1,8 +1,10 @@ - ============================================= - ASYMMETRIC / PUBLIC-KEY CRYPTOGRAPHY KEY TYPE - ============================================= +.. SPDX-License-Identifier: GPL-2.0 -Contents: +============================================= +Asymmetric / Public-key Cryptography Key Type +============================================= + +.. Contents: - Overview. - Key identification. @@ -13,8 +15,7 @@ Contents: - Keyring link restrictions. -======== -OVERVIEW +Overview ======== The "asymmetric" key type is designed to be a container for the keys used in @@ -42,8 +43,7 @@ key, or it may interpret it as a reference to a key held somewhere else in the system (for example, a TPM). -================== -KEY IDENTIFICATION +Key Identification ================== If a key is added with an empty name, the instantiation data parsers are given @@ -57,49 +57,48 @@ The asymmetric key type's match function can then perform a wider range of comparisons than just the straightforward comparison of the description with the criterion string: - (1) If the criterion string is of the form "id:<hexdigits>" then the match + 1) If the criterion string is of the form "id:<hexdigits>" then the match function will examine a key's fingerprint to see if the hex digits given - after the "id:" match the tail. For instance: + after the "id:" match the tail. For instance:: keyctl search @s asymmetric id:5acc2142 - will match a key with fingerprint: + will match a key with fingerprint:: 1A00 2040 7601 7889 DE11 882C 3823 04AD 5ACC 2142 - (2) If the criterion string is of the form "<subtype>:<hexdigits>" then the + 2) If the criterion string is of the form "<subtype>:<hexdigits>" then the match will match the ID as in (1), but with the added restriction that only keys of the specified subtype (e.g. tpm) will be matched. For - instance: + instance:: keyctl search @s asymmetric tpm:5acc2142 Looking in /proc/keys, the last 8 hex digits of the key fingerprint are -displayed, along with the subtype: +displayed, along with the subtype:: 1a39e171 I----- 1 perm 3f010000 0 0 asymmetric modsign.0: DSA 5acc2142 [] -========================= -ACCESSING ASYMMETRIC KEYS +Accessing Asymmetric Keys ========================= For general access to asymmetric keys from within the kernel, the following -inclusion is required: +inclusion is required:: #include <crypto/public_key.h> This gives access to functions for dealing with asymmetric / public keys. Three enums are defined there for representing public-key cryptography -algorithms: +algorithms:: enum pkey_algo -digest algorithms used by those: +digest algorithms used by those:: enum pkey_hash_algo -and key identifier representations: +and key identifier representations:: enum pkey_id_type @@ -110,25 +109,25 @@ PGP-specific metadata, whereas X.509 has arbitrary certificate identifiers. The operations defined upon a key are: - (1) Signature verification. + 1) Signature verification. Other operations are possible (such as encryption) with the same key data required for verification, but not currently supported, and others (eg. decryption and signature generation) require extra key data. -SIGNATURE VERIFICATION +Signature Verification ---------------------- An operation is provided to perform cryptographic signature verification, using -an asymmetric key to provide or to provide access to the public key. +an asymmetric key to provide or to provide access to the public key:: int verify_signature(const struct key *key, const struct public_key_signature *sig); The caller must have already obtained the key from some source and can then use it to check the signature. The caller must have parsed the signature and -transferred the relevant bits to the structure pointed to by sig. +transferred the relevant bits to the structure pointed to by sig:: struct public_key_signature { u8 *digest; @@ -159,8 +158,7 @@ data; or -ENOMEM if an allocation can't be performed. -EINVAL can be returned if the key argument is the wrong type or is incompletely set up. -======================= -ASYMMETRIC KEY SUBTYPES +Asymmetric Key Subtypes ======================= Asymmetric keys have a subtype that defines the set of operations that can be @@ -171,11 +169,11 @@ The subtype is selected by the key data parser and the parser must initialise the data required for it. The asymmetric key retains a reference on the subtype module. -The subtype definition structure can be found in: +The subtype definition structure can be found in:: #include <keys/asymmetric-subtype.h> -and looks like the following: +and looks like the following:: struct asymmetric_key_subtype { struct module *owner; @@ -198,39 +196,37 @@ the subtype. Currently, the name is only used for print statements. There are a number of operations defined by the subtype: - (1) describe(). + 1) describe(). Mandatory. This allows the subtype to display something in /proc/keys against the key. For instance the name of the public key algorithm type could be displayed. The key type will display the tail of the key identity string after this. - (2) destroy(). + 2) destroy(). Mandatory. This should free the memory associated with the key. The asymmetric key will look after freeing the fingerprint and releasing the reference on the subtype module. - (3) query(). + 3) query(). Mandatory. This is a function for querying the capabilities of a key. - (4) eds_op(). + 4) eds_op(). Optional. This is the entry point for the encryption, decryption and signature creation operations (which are distinguished by the operation ID in the parameter struct). The subtype may do anything it likes to implement an operation, including offloading to hardware. - (5) verify_signature(). + 5) verify_signature(). Optional. This is the entry point for signature verification. The subtype may do anything it likes to implement an operation, including offloading to hardware. - -========================== -INSTANTIATION DATA PARSERS +Instantiation Data Parsers ========================== The asymmetric key type doesn't generally want to store or to deal with a raw @@ -254,11 +250,11 @@ Examples of blob formats for which parsers could be implemented include: During key instantiation each parser in the list is tried until one doesn't return -EBADMSG. -The parser definition structure can be found in: +The parser definition structure can be found in:: #include <keys/asymmetric-parser.h> -and looks like the following: +and looks like the following:: struct asymmetric_key_parser { struct module *owner; @@ -273,7 +269,7 @@ the parser. There is currently only a single operation defined by the parser, and it is mandatory: - (1) parse(). + 1) parse(). This is called to preparse the key from the key creation and update paths. In particular, it is called during the key creation _before_ a key is @@ -282,7 +278,7 @@ mandatory: The caller passes a pointer to the following struct with all of the fields cleared, except for data, datalen and quotalen [see - Documentation/security/keys/core.rst]. + Documentation/security/keys/core.rst]:: struct key_preparsed_payload { char *description; @@ -321,7 +317,7 @@ mandatory: public-key algorithm such as RSA and DSA this will likely be a printable hex version of the key's fingerprint. -Functions are provided to register and unregister parsers: +Functions are provided to register and unregister parsers:: int register_asymmetric_key_parser(struct asymmetric_key_parser *parser); void unregister_asymmetric_key_parser(struct asymmetric_key_parser *subtype); @@ -330,8 +326,7 @@ Parsers may not have the same name. The names are otherwise only used for displaying in debugging messages. -========================= -KEYRING LINK RESTRICTIONS +Keyring Link Restrictions ========================= Keyrings created from userspace using add_key can be configured to check the @@ -340,7 +335,7 @@ allowed to link. Several restriction methods are available: - (1) Restrict using the kernel builtin trusted keyring + 1) Restrict using the kernel builtin trusted keyring - Option string used with KEYCTL_RESTRICT_KEYRING: - "builtin_trusted" @@ -350,7 +345,7 @@ Several restriction methods are available: rejected. The ca_keys kernel parameter also affects which keys are used for signature verification. - (2) Restrict using the kernel builtin and secondary trusted keyrings + 2) Restrict using the kernel builtin and secondary trusted keyrings - Option string used with KEYCTL_RESTRICT_KEYRING: - "builtin_and_secondary_trusted" @@ -361,7 +356,7 @@ Several restriction methods are available: kernel parameter also affects which keys are used for signature verification. - (3) Restrict using a separate key or keyring + 3) Restrict using a separate key or keyring - Option string used with KEYCTL_RESTRICT_KEYRING: - "key_or_keyring:<key or keyring serial number>[:chain]" @@ -378,7 +373,7 @@ Several restriction methods are available: certificate in order (starting closest to the root) to a keyring. For instance, one keyring can be populated with links to a set of root certificates, with a separate, restricted keyring set up for each - certificate chain to be validated: + certificate chain to be validated:: # Create and populate a keyring for root certificates root_id=`keyctl add keyring root-certs "" @s` @@ -400,7 +395,7 @@ Several restriction methods are available: one of the root certificates. A single keyring can be used to verify a chain of signatures by - restricting the keyring after linking the root certificate: + restricting the keyring after linking the root certificate:: # Create a keyring for the certificate chain and add the root chain2_id=`keyctl add keyring chain2 "" @s` diff --git a/Documentation/crypto/async-tx-api.txt b/Documentation/crypto/async-tx-api.rst index 7bf1be20d93a..bfc773991bdc 100644 --- a/Documentation/crypto/async-tx-api.txt +++ b/Documentation/crypto/async-tx-api.rst @@ -1,27 +1,32 @@ - Asynchronous Transfers/Transforms API +.. SPDX-License-Identifier: GPL-2.0 -1 INTRODUCTION +===================================== +Asynchronous Transfers/Transforms API +===================================== -2 GENEALOGY +.. Contents -3 USAGE -3.1 General format of the API -3.2 Supported operations -3.3 Descriptor management -3.4 When does the operation execute? -3.5 When does the operation complete? -3.6 Constraints -3.7 Example + 1. INTRODUCTION -4 DMAENGINE DRIVER DEVELOPER NOTES -4.1 Conformance points -4.2 "My application needs exclusive control of hardware channels" + 2 GENEALOGY -5 SOURCE + 3 USAGE + 3.1 General format of the API + 3.2 Supported operations + 3.3 Descriptor management + 3.4 When does the operation execute? + 3.5 When does the operation complete? + 3.6 Constraints + 3.7 Example ---- + 4 DMAENGINE DRIVER DEVELOPER NOTES + 4.1 Conformance points + 4.2 "My application needs exclusive control of hardware channels" -1 INTRODUCTION + 5 SOURCE + +1. Introduction +=============== The async_tx API provides methods for describing a chain of asynchronous bulk memory transfers/transforms with support for inter-transactional @@ -31,7 +36,8 @@ that is written to the API can optimize for asynchronous operation and the API will fit the chain of operations to the available offload resources. -2 GENEALOGY +2.Genealogy +=========== The API was initially designed to offload the memory copy and xor-parity-calculations of the md-raid5 driver using the offload engines @@ -39,40 +45,52 @@ present in the Intel(R) Xscale series of I/O processors. It also built on the 'dmaengine' layer developed for offloading memory copies in the network stack using Intel(R) I/OAT engines. The following design features surfaced as a result: -1/ implicit synchronous path: users of the API do not need to know if + +1. implicit synchronous path: users of the API do not need to know if the platform they are running on has offload capabilities. The operation will be offloaded when an engine is available and carried out in software otherwise. -2/ cross channel dependency chains: the API allows a chain of dependent +2. cross channel dependency chains: the API allows a chain of dependent operations to be submitted, like xor->copy->xor in the raid5 case. The API automatically handles cases where the transition from one operation to another implies a hardware channel switch. -3/ dmaengine extensions to support multiple clients and operation types +3. dmaengine extensions to support multiple clients and operation types beyond 'memcpy' -3 USAGE +3. Usage +======== + +3.1 General format of the API +----------------------------- + +:: + + struct dma_async_tx_descriptor * + async_<operation>(<op specific parameters>, struct async_submit ctl *submit) -3.1 General format of the API: -struct dma_async_tx_descriptor * -async_<operation>(<op specific parameters>, struct async_submit ctl *submit) +3.2 Supported operations +------------------------ -3.2 Supported operations: -memcpy - memory copy between a source and a destination buffer -memset - fill a destination buffer with a byte value -xor - xor a series of source buffers and write the result to a +======== ==================================================================== +memcpy memory copy between a source and a destination buffer +memset fill a destination buffer with a byte value +xor xor a series of source buffers and write the result to a destination buffer -xor_val - xor a series of source buffers and set a flag if the +xor_val xor a series of source buffers and set a flag if the result is zero. The implementation attempts to prevent writes to memory -pq - generate the p+q (raid6 syndrome) from a series of source buffers -pq_val - validate that a p and or q buffer are in sync with a given series of +pq generate the p+q (raid6 syndrome) from a series of source buffers +pq_val validate that a p and or q buffer are in sync with a given series of sources -datap - (raid6_datap_recov) recover a raid6 data block and the p block +datap (raid6_datap_recov) recover a raid6 data block and the p block from the given sources -2data - (raid6_2data_recov) recover 2 raid6 data blocks from the given +2data (raid6_2data_recov) recover 2 raid6 data blocks from the given sources +======== ==================================================================== + +3.3 Descriptor management +------------------------- -3.3 Descriptor management: The return value is non-NULL and points to a 'descriptor' when the operation has been queued to execute asynchronously. Descriptors are recycled resources, under control of the offload engine driver, to be reused as @@ -82,12 +100,15 @@ before the dependency is submitted. This requires that all descriptors be acknowledged by the application before the offload engine driver is allowed to recycle (or free) the descriptor. A descriptor can be acked by one of the following methods: -1/ setting the ASYNC_TX_ACK flag if no child operations are to be submitted -2/ submitting an unacknowledged descriptor as a dependency to another + +1. setting the ASYNC_TX_ACK flag if no child operations are to be submitted +2. submitting an unacknowledged descriptor as a dependency to another async_tx call will implicitly set the acknowledged state. -3/ calling async_tx_ack() on the descriptor. +3. calling async_tx_ack() on the descriptor. 3.4 When does the operation execute? +------------------------------------ + Operations do not immediately issue after return from the async_<operation> call. Offload engine drivers batch operations to improve performance by reducing the number of mmio cycles needed to @@ -98,12 +119,15 @@ channels since the application has no knowledge of channel to operation mapping. 3.5 When does the operation complete? +------------------------------------- + There are two methods for an application to learn about the completion of an operation. -1/ Call dma_wait_for_async_tx(). This call causes the CPU to spin while + +1. Call dma_wait_for_async_tx(). This call causes the CPU to spin while it polls for the completion of the operation. It handles dependency chains and issuing pending operations. -2/ Specify a completion callback. The callback routine runs in tasklet +2. Specify a completion callback. The callback routine runs in tasklet context if the offload engine driver supports interrupts, or it is called in application context if the operation is carried out synchronously in software. The callback can be set in the call to @@ -111,83 +135,95 @@ of an operation. unknown length it can use the async_trigger_callback() routine to set a completion interrupt/callback at the end of the chain. -3.6 Constraints: -1/ Calls to async_<operation> are not permitted in IRQ context. Other +3.6 Constraints +--------------- + +1. Calls to async_<operation> are not permitted in IRQ context. Other contexts are permitted provided constraint #2 is not violated. -2/ Completion callback routines cannot submit new operations. This +2. Completion callback routines cannot submit new operations. This results in recursion in the synchronous case and spin_locks being acquired twice in the asynchronous case. -3.7 Example: +3.7 Example +----------- + Perform a xor->copy->xor operation where each operation depends on the -result from the previous operation: - -void callback(void *param) -{ - struct completion *cmp = param; - - complete(cmp); -} - -void run_xor_copy_xor(struct page **xor_srcs, - int xor_src_cnt, - struct page *xor_dest, - size_t xor_len, - struct page *copy_src, - struct page *copy_dest, - size_t copy_len) -{ - struct dma_async_tx_descriptor *tx; - addr_conv_t addr_conv[xor_src_cnt]; - struct async_submit_ctl submit; - addr_conv_t addr_conv[NDISKS]; - struct completion cmp; - - init_async_submit(&submit, ASYNC_TX_XOR_DROP_DST, NULL, NULL, NULL, - addr_conv); - tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, &submit) - - submit->depend_tx = tx; - tx = async_memcpy(copy_dest, copy_src, 0, 0, copy_len, &submit); - - init_completion(&cmp); - init_async_submit(&submit, ASYNC_TX_XOR_DROP_DST | ASYNC_TX_ACK, tx, - callback, &cmp, addr_conv); - tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, &submit); - - async_tx_issue_pending_all(); - - wait_for_completion(&cmp); -} +result from the previous operation:: + + void callback(void *param) + { + struct completion *cmp = param; + + complete(cmp); + } + + void run_xor_copy_xor(struct page **xor_srcs, + int xor_src_cnt, + struct page *xor_dest, + size_t xor_len, + struct page *copy_src, + struct page *copy_dest, + size_t copy_len) + { + struct dma_async_tx_descriptor *tx; + addr_conv_t addr_conv[xor_src_cnt]; + struct async_submit_ctl submit; + addr_conv_t addr_conv[NDISKS]; + struct completion cmp; + + init_async_submit(&submit, ASYNC_TX_XOR_DROP_DST, NULL, NULL, NULL, + addr_conv); + tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, &submit) + + submit->depend_tx = tx; + tx = async_memcpy(copy_dest, copy_src, 0, 0, copy_len, &submit); + + init_completion(&cmp); + init_async_submit(&submit, ASYNC_TX_XOR_DROP_DST | ASYNC_TX_ACK, tx, + callback, &cmp, addr_conv); + tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, &submit); + + async_tx_issue_pending_all(); + + wait_for_completion(&cmp); + } See include/linux/async_tx.h for more information on the flags. See the ops_run_* and ops_complete_* routines in drivers/md/raid5.c for more implementation examples. -4 DRIVER DEVELOPMENT NOTES +4. Driver Development Notes +=========================== + +4.1 Conformance points +---------------------- -4.1 Conformance points: There are a few conformance points required in dmaengine drivers to accommodate assumptions made by applications using the async_tx API: -1/ Completion callbacks are expected to happen in tasklet context -2/ dma_async_tx_descriptor fields are never manipulated in IRQ context -3/ Use async_tx_run_dependencies() in the descriptor clean up path to + +1. Completion callbacks are expected to happen in tasklet context +2. dma_async_tx_descriptor fields are never manipulated in IRQ context +3. Use async_tx_run_dependencies() in the descriptor clean up path to handle submission of dependent operations 4.2 "My application needs exclusive control of hardware channels" +----------------------------------------------------------------- + Primarily this requirement arises from cases where a DMA engine driver is being used to support device-to-memory operations. A channel that is performing these operations cannot, for many platform specific reasons, be shared. For these cases the dma_request_channel() interface is provided. -The interface is: -struct dma_chan *dma_request_channel(dma_cap_mask_t mask, - dma_filter_fn filter_fn, - void *filter_param); +The interface is:: -Where dma_filter_fn is defined as: -typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param); + struct dma_chan *dma_request_channel(dma_cap_mask_t mask, + dma_filter_fn filter_fn, + void *filter_param); + +Where dma_filter_fn is defined as:: + + typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param); When the optional 'filter_fn' parameter is set to NULL dma_request_channel simply returns the first channel that satisfies the @@ -207,19 +243,28 @@ private. Alternatively, it is set when dma_request_channel() finds an unused "public" channel. A couple caveats to note when implementing a driver and consumer: -1/ Once a channel has been privately allocated it will no longer be + +1. Once a channel has been privately allocated it will no longer be considered by the general-purpose allocator even after a call to dma_release_channel(). -2/ Since capabilities are specified at the device level a dma_device +2. Since capabilities are specified at the device level a dma_device with multiple channels will either have all channels public, or all channels private. -5 SOURCE - -include/linux/dmaengine.h: core header file for DMA drivers and api users -drivers/dma/dmaengine.c: offload engine channel management routines -drivers/dma/: location for offload engine drivers -include/linux/async_tx.h: core header file for the async_tx api -crypto/async_tx/async_tx.c: async_tx interface to dmaengine and common code -crypto/async_tx/async_memcpy.c: copy offload -crypto/async_tx/async_xor.c: xor and xor zero sum offload +5. Source +--------- + +include/linux/dmaengine.h: + core header file for DMA drivers and api users +drivers/dma/dmaengine.c: + offload engine channel management routines +drivers/dma/: + location for offload engine drivers +include/linux/async_tx.h: + core header file for the async_tx api +crypto/async_tx/async_tx.c: + async_tx interface to dmaengine and common code +crypto/async_tx/async_memcpy.c: + copy offload +crypto/async_tx/async_xor.c: + xor and xor zero sum offload diff --git a/Documentation/crypto/descore-readme.txt b/Documentation/crypto/descore-readme.rst index 16e9e6350755..45bd9c8babf4 100644 --- a/Documentation/crypto/descore-readme.txt +++ b/Documentation/crypto/descore-readme.rst @@ -1,8 +1,20 @@ -Below is the original README file from the descore.shar package. +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=========================================== +Fast & Portable DES encryption & decryption +=========================================== + +.. note:: + + Below is the original README file from the descore.shar package, + converted to ReST format. + ------------------------------------------------------------------------------ des - fast & portable DES encryption & decryption. -Copyright (C) 1992 Dana L. How + +Copyright |copy| 1992 Dana L. How This program is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by @@ -20,13 +32,12 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. Author's address: how@isl.stanford.edu -$Id: README,v 1.15 1992/05/20 00:25:32 how E $ - - -==>> To compile after untarring/unsharring, just `make' <<== +.. README,v 1.15 1992/05/20 00:25:32 how E +==>> To compile after untarring/unsharring, just ``make`` <<== This package was designed with the following goals: + 1. Highest possible encryption/decryption PERFORMANCE. 2. PORTABILITY to any byte-addressable host with a 32bit unsigned C type 3. Plug-compatible replacement for KERBEROS's low-level routines. @@ -36,7 +47,7 @@ register-starved machines. My discussions with Richard Outerbridge, 71755.204@compuserve.com, sparked a number of these enhancements. To more rapidly understand the code in this package, inspect desSmallFips.i -(created by typing `make') BEFORE you tackle desCode.h. The latter is set +(created by typing ``make``) |