Control of access to a memory by a device

A method of controlling access to a memory in a data processing apparatus having a secure domain and a non-secure domain, in the secure domain the data processing apparatus having access to secure data which is not accessible in the non-secure domain, the data processing apparatus comprising a device bus, a device coupled to the device bus and operable to issue a memory access request pertaining to either said secure domain or said non-secure domain, and a memory coupled to the device bus and operable to store data required by the device, the memory comprising secure memory for storing secure data and non-secure memory for storing non-secure data, the method comprising the steps of:

• (i) issuing from the device onto the device bus a memory access request when access to an item of data in the memory is required;
• and
• (ii) whenever the memory access request as issued by the device pertains to said non-secure domain, employing partition checking logic coupled to the device bus to detect if the memory access request is seeking to access the secure memory;
• and
• (iii) upon such detection, preventing the access specified by that memory access request.

A data processing apparatus, comprising:

• a device bus;
• a device coupled to the device bus and operable in a plurality of modes and either a secure domain or a non-secure domain, including at least one non-secure mode being a mode in the non-secure domain and at least one secure mode being a mode in the secure domain;
• a memory coupled to the device bus and operable to store data required by the device, the memory comprising secure memory for storing secure data and non-secure memory for storing non-secure data, the device being operable to issue onto the device bus a memory access request when access to an item of data in the memory is required;
• and
• partition checking logic coupled to the device bus and operable whenever the memory access request is issued by the device when operating in said at least one non-secure mode to detect if the memory access request is seeking to access the secure memory, and upon such detection to prevent the access specified by that memory access request.

A method of controlling access to a memory in a data processing apparatus, the data processing apparatus comprising a device bus, a device coupled to the device bus and operable in a plurality of modes and either a secure domain or a non-secure domain, including at least one non-secure mode being a mode in the non-secure domain and at least one secure mode being a mode in the secure domain, and a memory coupled to the device bus and operable to store data required by the device, the memory comprising secure memory for storing secure data and non-secure memory for storing non-secure data, the method comprising the steps of:

• (i) issuing from the device onto the device bus a memory access request when access to an item of data in the memory is required;
• and
• (ii) whenever the memory access request is issued by the device when operating in said at least one non-secure mode, employing partition checking logic coupled to the device bus to detect if the memory access request is seeking to access the secure memory;
• and
• (iii) upon such detection, preventing the access specified by that memory access request.