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

Abstract

The present invention discloses a method and system for managing the kernel memory of an operating system in a user state, which calculates the real starting kernel virtual address and the real ending kernel virtual address of the kernel object, and transfers these two addresses to the kernel memory registration table module, Creating the thread kernel object of the user-mode program within the memory range of the absolute start address specified by the user can greatly increase the flexibility of managing kernel memory in the user-mode while reducing the memory and system burden required for this function. The kernel memory management strength of the present invention can be any fine granularity defined by the user, greatly reducing the possibility of incorrect implementation, so that the application program does not need to know the real kernel virtual address, reducing the possibility of hidden storage channels, and is suitable for 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) Existing seL4 and other mechanisms that allow redefining pages as 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 needs to create kernel objects, then the kernel objects 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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