In Linux, the allocation of buffer memory at a specific physical address can be achieved using the following steps:
- Reserve the required physical memory range: You can reserve a specific physical address range by modifying the kernel's boot parameters. Typically, this involves passing the "memmap" parameter to the kernel during boot time. The "memmap" parameter specifies the range of physical memory that should be reserved, and it is specified in the format
- Disable memory management features: To prevent the Linux kernel from managing the reserved memory range, certain memory management features need to be disabled. For example, you may need to disable the dynamic memory allocation by configuring the kernel to use a fixed-size initial RAM disk (initrd) or using the "mem=" parameter in the boot options to specify the total amount of memory usable by the kernel.
- Implement custom memory management: Since the Linux kernel normally manages physical memory dynamically, you will need to implement custom memory management to allocate and free memory at the specific physical address. This can be achieved using kernel APIs like __pa() and ioremap() to translate between virtual and physical addresses, and to allocate memory within the reserved range.
Keep in mind that the process of allocating memory at a specific physical address in Linux requires expertise in kernel development and may involve modifying the kernel source code. It is recommended to consult official Linux documentation, kernel mailing lists, or expert guidance to ensure the correct implementation of these steps.