mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2025-05-06 19:22:53 +00:00
31 lines
876 B
Markdown
31 lines
876 B
Markdown
## Name
|
|
|
|
mem - physical system memory
|
|
|
|
## Description
|
|
|
|
`/dev/mem` is a character device file that is used by other programs to examine
|
|
the physical memory.
|
|
|
|
Trying to [`mmap`(2)](../mmap.md) a physical range results either with success,
|
|
or with an error. When invoking [`mmap`(2)](../mmap.md) on bad memory range,
|
|
the kernel will write a message about it to the kernel log.
|
|
|
|
By default, the kernel limits the areas which can be accessed. The allowed areas
|
|
are the reserved ranges in physical memory, essentially limiting the access to
|
|
ROMs and memory-mapped PCI regions on x86.
|
|
|
|
To create it manually:
|
|
```sh
|
|
mknod /dev/mem c 1 1
|
|
chmod 660 /dev/mem
|
|
```
|
|
|
|
## Returned error values after [`mmap`(2)](../mmap.md)
|
|
|
|
* `EINVAL`: An access violation was detected.
|
|
* `ENOMEM`: The requested range would wrap around, creating an access violation.
|
|
|
|
## See also
|
|
|
|
* [`mmap`(2)](../mmap.md)
|