linux kernel - reserve system memory, ioremap()? -

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is bad call ioremap() on system dram. reserve space in system dram not used other process. way it? know dram not io memory wasn't sure if considered bad practice.

is bad call ioremap() on system dram.

system memory managed kernel should not remapped using ioremap(). these multiple mappings can cause data corruption on architectures/processors. refer this article on issue arm.

you try ensure single mapping (using ioremap()) excluding memory region in question @ boot time kernel's management.
on arm specify reduced physical memory using atags (the atag_mem tag(s)) or device tree (the memory property).
otherwise use memmap= kernel parameter in kernel command line:

1835         memmap=nn[kmg]$ss[kmg] 1836                         [knl,acpi] mark specific memory reserved. 1837                         region of memory reserved ss ss+nn. 1838                         example: exclude memory 0x18690000-0x1869ffff 1839                                  memmap=64k$0x18690000 1840                                  or 1841                                  memmap=0x10000$0x18690000

the memory region should declared through request_mem_region() prevent multiple requests , completeness/accuracy of /proc/iomem.


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