Access control apparatus, access control system, processor, access control method, memory access control apparatus, memory access control system, and memory access control method
First Claim
1. An access control apparatus to control an access among a writer, a reader, and a memory, comprising:
- a parity generator that generates a parity for original data to be written into the memory;
a parity adder that generates parity-added data by adding the parity generated by the parity generator to the original data;
a first syndrome generator that generates a first syndrome which is a value associated with a first access code used by the writer to request writing of the original data into the memory;
a first mask generator that generates the first mask data, based on the first syndrome, the first access code, and a first memory address at which the original data is to be written by the writer;
a first XOR unit that obtains first post-operation data by calculating an XOR between the parity-added data and the first mask data;
a writing unit that writes the first post-operation data into the memory;
a second syndrome generator that generates a second syndrome which is a value associated with a second access code used by the reader to request reading of data from the memory;
a second mask generator that generates the second mask data, based on the second syndrome, the second access code, and a second memory address from which the data is to be read by the reader;
a reading unit that reads the first post-operation data from the memory;
a second XOR unit that obtains second post-operation data by calculating an XOR between the second mask data and the first post-operation data;
a data syndrome calculator that calculates a real data syndrome based on the second post-operation data; and
an output determining unit that determines whether the second post-operation data is to be output as the original data, based on the real data syndrome.
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Accused Products
Abstract
An access control apparatus includes a parity generator that generates a parity for original data to be written into a memory; and a parity adder that generates parity-added data by adding the parity to the original data; a first syndrome generator that generates a first syndrome of first mask data to mask the parity-added data. The first syndrome is a value associated beforehand with a first access code to be used when a writer accesses the memory. The apparatus also includes a first mask generator that generates the first mask data based on the first syndrome, the first access code, and a first memory address; a first XOR unit that obtains first post-operation data by calculating an XOR between the parity-added data and the first mask data; and a writing unit that writes the first post-operation data into the memory.
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Citations
28 Claims
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1. An access control apparatus to control an access among a writer, a reader, and a memory, comprising:
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a parity generator that generates a parity for original data to be written into the memory;
a parity adder that generates parity-added data by adding the parity generated by the parity generator to the original data;
a first syndrome generator that generates a first syndrome which is a value associated with a first access code used by the writer to request writing of the original data into the memory;
a first mask generator that generates the first mask data, based on the first syndrome, the first access code, and a first memory address at which the original data is to be written by the writer;
a first XOR unit that obtains first post-operation data by calculating an XOR between the parity-added data and the first mask data;
a writing unit that writes the first post-operation data into the memory;
a second syndrome generator that generates a second syndrome which is a value associated with a second access code used by the reader to request reading of data from the memory;
a second mask generator that generates the second mask data, based on the second syndrome, the second access code, and a second memory address from which the data is to be read by the reader;
a reading unit that reads the first post-operation data from the memory;
a second XOR unit that obtains second post-operation data by calculating an XOR between the second mask data and the first post-operation data;
a data syndrome calculator that calculates a real data syndrome based on the second post-operation data; and
an output determining unit that determines whether the second post-operation data is to be output as the original data, based on the real data syndrome. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An access control system comprising:
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a processor;
a memory controller; and
a memory access control apparatus that controls access to a memory, the memory access control apparatus comprising a parity generator that generates a parity for original data to be written into the memory;
a parity adder that generates parity-added data by adding the parity generated by the parity generator to the original data;
a first syndrome generator that generates a first syndrome of first mask data to mask the parity-added data, the first syndrome being a value associated beforehand with a first access code that is information to be used when a writer accesses the memory, the writer requesting writing of the original data into the memory;
a first mask generator that generates the first mask data, based on the first syndrome, the first access code, and a first memory address at which the original data is to be written;
a first XOR unit that obtains first post-operation data by calculating an XOR between the parity-added data and the first mask data;
a writing unit that writes the first post-operation data into the memory;
a second syndrome generator that generates a second syndrome of second mask data to mask the first post-operation data, the second syndrome being a value associated beforehand with a second access code that is information to be used when a reader accesses the memory, the reader requesting reading of data from the memory;
a second mask generator that generates the second mask data, based on the second syndrome, the second access code, and a second memory address from which the data is to be read;
a reading unit that reads the first post-operation data from the memory;
a second XOR unit that obtains second post-operation data by calculating an XOR between the second mask data and the first post-operation data;
a data syndrome calculator that calculates a real data syndrome based on the second post-operation data; and
an output determining unit that determines whether the second post-operation data is to be output as the original data, based on the real data syndrome.
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20. An access control system comprising:
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a processor; and
a memory access control apparatus that controls access to a memory, the memory access control apparatus comprising a parity generator that generates a parity for original data to be written into the memory;
a parity adder that generates parity-added data by adding the parity generated by the parity generator to the original data;
a first syndrome generator that generates a first syndrome of first mask data to mask the parity-added data, the first syndrome being a value associated beforehand with a first access code that is information to be used when a writer accesses the memory, the writer requesting writing of the original data into the memory;
a first mask generator that generates the first mask data, based on the first syndrome, the first access code, and a first memory address at which the original data is to be written;
a first XOR unit that obtains first post-operation data by calculating an XOR between the parity-added data and the first mask data;
a writing unit that writes the first post-operation data into the memory;
a second syndrome generator that generates a second syndrome of second mask data to mask the first post-operation data, the second syndrome being a value associated beforehand with a second access code that is information to be used when a reader accesses the memory, the reader requesting reading of data from the memory;
a second mask generator that generates the second mask data, based on the second syndrome, the second access code, and a second memory address from which the data is to be read;
a reading unit that reads the first post-operation data from the memory;
a second XOR unit that obtains second post-operation data by calculating an XOR between the second mask data and the first post-operation data;
a data syndrome calculator that calculates a real data syndrome based on the second post-operation data; and
an output determining unit that determines whether the second post-operation data is to be output as the original data, based on the real data syndrome.
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21. A processor that is equipped with a memory controller and a memory access control apparatus that controls access to a memory,
the processor comprising: -
a parity generator that generates a parity for original data to be written into the memory;
a parity adder that generates parity-added data by adding the parity generated by the parity generator to the original data;
a first syndrome generator that generates a first syndrome of first mask data to mask the parity-added data, the first syndrome being a value associated beforehand with a first access code that is information to be used when a writer accesses the memory, the writer requesting writing of the original data into the memory;
a first mask generator that generates the first mask data, based on the first syndrome, the first access code, and a first memory address at which the original data is to be written;
a first XOR unit that obtains first post-operation data by calculating an XOR between the parity-added data and the first mask data;
a writing unit that writes the first post-operation data into the memory;
a second syndrome generator that generates a second syndrome of second mask data to mask the first post-operation data, the second syndrome being a value associated beforehand with a second access code that is information to be used when a reader accesses the memory, the reader requesting reading of data from the memory;
a second mask generator that generates the second mask data, based on the second syndrome, the second access code, and a second memory address from which the data is to be read;
a reading unit that reads the first post-operation data from the memory;
a second XOR unit that obtains second post-operation data by calculating an XOR between the second mask data and the first post-operation data;
a data syndrome calculator that calculates a real data syndrome based on the second post-operation data; and
an output determining unit that determines whether the second post-operation data is to be output as the original data, based on the real data syndrome.
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22. An access control method comprising:
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generating a parity for original data to be written into a memory;
generating parity-added data by adding the parity generated to the original data;
generating a first syndrome of first mask data to mask the parity-added data, the first syndrome being a value associated beforehand with a first access code that is information to be used when a writer accesses the memory, the writer requesting writing of the original data into the memory;
generating the first mask data based on the first syndrome, the first access code, and a first memory address at which the original data is to be written;
acquiring first post-operation data by calculating an XOR between the parity-added data and the first mask data;
writing the first post-operation data into the memory;
generating a second syndrome of second mask data to mask the first post-operation data, the second syndrome being a value associated beforehand with a second access code that is information to be used when a reader accesses the memory, the reader requesting reading of data from the memory;
generator that generates the second mask data, based on the second syndrome, the second access code, and a second memory address from which the data is to be read;
reading the first post-operation data from the memory;
obtaining second post-operation data by calculating an XOR between the second mask data and the first post-operation data;
calculating a real data syndrome based on the second post-operation data; and
determining whether the second post-operation data is to be output as the original data, based on the real data syndrome.
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23. A memory access control apparatus, comprising:
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a read request acquirer that acquires data to be read from a memory, and a memory address at which the data is to be read, the data and the memory address being acquired from a reader that requests the reading of the data from the memory;
a cache memory monitor that determines whether the memory address acquired by the read request acquirer is stored in a cache memory that stores data, a memory address of the data, and a requester access code in association with one another, the data being requested to be written into the memory by a writer that requests writing of the data into the memory or being requested to be read from the memory by the reader, the requester access code being information to be used when a writer or a reader that is allowed to access the data accesses the memory;
an access code comparator that compares the requester access code, which is associated with the memory address in the cache memory, with a second access code that is information to be used by the reader to access the memory, when the cache memory monitor determines that the memory address is stored in the cache memory; and
an output unit that outputs the data associated with the memory address in the cache memory to the reader, when the requestor access code matches the second access code. - View Dependent Claims (24, 25, 26)
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27. An access control system comprising:
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a processor;
a cache memory; and
a memory access control apparatus that controls access to a memory, the cache memory storing data requested by a writer that request writing of the data into the memory or a reader that requests reading of the data from the memory, a memory address of the data, and a requester access code that is information to be used when a writer or a reader that is allowed to access the data accesses the memory, the data and the memory address being associated with the requestor access code, the memory access control apparatus comprising a read request acquirer that acquires from the reader the data to be read from the memory and the memory address of the data;
a cache memory monitor that determines whether the memory address acquired by the read request acquirer is stored in the cache memory;
an access code comparator that compares the requester access code associated with the memory address in the cache memory with a second access code that is information to be used by the reader to access the memory, when the cache memory monitor determines that the memory address is stored in the cache memory; and
an output unit that outputs the data associated with the memory address in the cache memory to the reader, when the requester access code matches the second access code.
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28. A memory access control method, comprising:
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acquiring data to be read from a memory and a memory address at which the data is to be read, the data and the memory address being acquired from a reader that requests the reading of the data from the memory;
determining whether the memory address acquired is stored in a cache memory that stores data, a memory address of the data, and a requestor access code in association with one another, the data being requested to be written into the memory by a writer that requests writing of the data into the memory or being requested to be read from the memory by the reader, the requester access code being information to be used when a writer or a reader that has a right of access to the data accesses the memory;
comparing the requester access code, which is associated with the memory address in the cache memory, with a second access code that is information to be used by the reader to access the memory, when the memory address is stored in the cache memory; and
outputting the data associated with the memory address in the cache memory to the reader, when the requestor access code matches the second access code.
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Specification