A method and a system for managing a kernel memory of an operating system in a user mode

Abstract

The invention discloses a method and a system for managing a kernel memory of an operating system in a user mode. The method comprises steps that a real starting kernel virtual address and a real terminating kernel virtual address of the kernel object are calculated; and the two addresses are transmitted to the kernel memory registration table module, and a thread kernel object of the user mode program is created within the memory range of the absolute initial address specified by the user, so that the flexibility of managing the kernel memory by the user mode can be greatly improved, and meanwhile, the memory required for realizing the function and the system load are reduced. The kernel memory management strength can be any fine granularity defined by a user, the possibility of incorrectimplementation is greatly reduced, an application program does not need to know a real kernel virtual address, the possibility of existence of a hidden storage channel is reduced, and the method is suitable for a micro-kernel operating system.

Description

technical field [0001] The present disclosure relates to the field of Internet of Things, embedded systems, and operating system technologies, in particular to a method and system for managing operating system kernel memory in a user state, and is especially applicable to the field of managing kernel memory in a user state of a microkernel operating system. Background technique [0002] An important feature of modern microkernels is that their kernel memory is managed by userland. This enables the kernel memory originally in the kernel to be managed by a server with corresponding authorization in the user mode, and its specific management policies can be completed in the user mode, which increases the flexibility of the system. [0003] There are two types of existing kernel memory management techniques. One is managed in kernel mode, and the other is managed in user mode. Existing popular operating systems such as Linux manage kernel memory completely in the kernel state,...

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Problems solved by technology

However, the kernel memory allocation granularity of this interface is in units of pages, which is very inflexible, and recording the redefinition data itself is very burdensome on small embedded systems

[0004] The kernel memory management method of the existing operating system is not flexible enough:

[0005] (1) Operating systems such as Linux based on POSIX API do not allow users to manage kernel memory in user mode at all;

[0006] (2) The existing seL4 and other mechanisms that allow redefining pages into kernel memory pages and user memory pages can only manage kernel memory at the page level, and the granularity is too coarse;

[0007] (3) According to the existing seL4 kernel memory management mechanism, if the kernel memory is to create a kernel object, then the kernel object on the same page must be of the same type, which imposes many restrictions on the use of kernel objects in user mode

Moreover, this limits the ability to use large pages to store kernel objects: if large pages are used, the kernel objects on a large page must be of the same type. If these kernel objects cannot be used up, the space of these kernel objects is wasted;

[0008] (4) According to the existing seL4 kernel memory management mechanism, any page may be defined as a kernel memory page or a user memory page, so a large number of data structures and reference counts should be reserved to store these definition information, which is very important for small embedded system creates enormous storage pressure

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