Semiconductor device and its memory access control method
First Claim
1. A semiconductor device comprising:
- a main-arithmetic unit configured to execute a program;
a sub-arithmetic unit configured to execute a process of a part of the program executed by the main-arithmetic unit; and
a shared memory configured to be accessed by the main-arithmetic unit and the sub-arithmetic unit,wherein the sub-arithmetic unit comprises;
a register configured to store an access permission range address value provided from the main-arithmetic unit;
an information processing unit configured to execute a predetermined process according to an operation instruction provided from the main-arithmetic unit; and
a memory protection unit configured to provide, among access requests issued from the information processing unit to the shared memory, an access request for an address within an access permission range specified by the access permission range address value to the shared memory, and block an access request for an address outside the access permission range specified by the access permission range address value;
wherein the main-arithmetic unit executes, as the program, a reliability-verified program having a high reliability and a reliability-unverified program having a reliability lower than that of the reliability-verified program, and a process for storing the access permission range address value into the register of the sub-arithmetic unit is performed by the reliability-verified program.
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Accused Products
Abstract
There is a problem that memory protection against access to a shared memory by a sub-arithmetic unit used by a program executed in a main-arithmetic unit cannot be performed in a related-art semiconductor device. According to one embodiment, a semiconductor device includes a sub-arithmetic unit configured to execute a process of a part of a program executed by a main-arithmetic unit, and a shared memory shared by the main-arithmetic unit and the sub-arithmetic unit, in which the sub-arithmetic unit includes a memory protection unit configured to permit or prohibit access to the shared memory based on an access permission range address value provided from the main-arithmetic unit, the access to the shared memory being access that arises from a process executed by the sub-arithmetic unit.
32 Citations
18 Claims
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1. A semiconductor device comprising:
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a main-arithmetic unit configured to execute a program; a sub-arithmetic unit configured to execute a process of a part of the program executed by the main-arithmetic unit; and a shared memory configured to be accessed by the main-arithmetic unit and the sub-arithmetic unit, wherein the sub-arithmetic unit comprises; a register configured to store an access permission range address value provided from the main-arithmetic unit; an information processing unit configured to execute a predetermined process according to an operation instruction provided from the main-arithmetic unit; and a memory protection unit configured to provide, among access requests issued from the information processing unit to the shared memory, an access request for an address within an access permission range specified by the access permission range address value to the shared memory, and block an access request for an address outside the access permission range specified by the access permission range address value;
wherein the main-arithmetic unit executes, as the program, a reliability-verified program having a high reliability and a reliability-unverified program having a reliability lower than that of the reliability-verified program, and a process for storing the access permission range address value into the register of the sub-arithmetic unit is performed by the reliability-verified program. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 16, 17, 18)
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10. A memory access control method performed in semiconductor device, wherein the semiconductor device comprises:
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a main-arithmetic unit configured to execute a program; a sub-arithmetic unit configured to execute a process of a part of the program executed by the main-arithmetic unit, the sub-arithmetic unit including a register configured to store an access permission range address value provided from the main-arithmetic unit; and a shared memory configured to be accessed by the main-arithmetic unit and the sub-arithmetic unit, the memory access control method comprising; the sub-arithmetic unit executing a predetermined process according to an operation instruction provided from the main-arithmetic unit; and the sub-arithmetic unit providing, among access requests issued to the shared memory according to the predetermined process, an access request for an address within an access permission range specified by the access permission range address value to the shared memory and blocking an access request for an address outside the access permission range specified by the access permission range address value;
wherein the main-arithmetic unit executes, as the program, a reliability-verified program having a high reliability and a reliability-unverified program having a reliability lower than that of the reliability-verified program, and a process for storing the access permission range address value into the register of the sub-arithmetic unit is performed by the reliability-verified program. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification