I would like to ask a few simple questions on linux memory layout.
It would be nice if someone could comment on the following.
Let's say I have an intel box with 1GB of physical RAM.
The virtual address of that RAM in kernel space begins at c0000000
In the lower 4MB are things like video ROM, pagetables, the zero-page,
and the ioport mappings for PCI and ISA devices, right ?
The kernel code and data starts behind that low 4MB as
seen in /proc/iomem.
That means that a little less than 1GB can be mapped as physical RAM.
Now when (for example) my matrox framebuffer mapps its on-board
RAM to a kernel virtual address, where will that be ?
If I have 1GB RAM, there's no virtual address space left to
map the framebuffer. How does that kind of mapping work ?
cheers,
Patrick
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