>>>>> "Timur" == Timur Tabi <ttabi@interactivesi.com> writes:
Timur> I'm studying the code for __ioremap and I'm confused by
Timur> something. The phys_to_virt and virt_to_phys macros are very
Timur> simple. Basically, in kernel space, the virtual address is an
Timur> offset of the physical address, so it's very simple.
You are making a bad assumption here, that PCI shared memory can be
treated as regular memory which it cannot.
Timur> 1) Doesn't this mapping break the phys_to_virt and virt_to_phys
Timur> macros?
Those two macros are not defined on ioremap'ed regions so it is
irrelevant.
Timur> 2) kmalloc takes real physical memory from the kernel heap.
Timur> But then the virtual addresses are remapped to other physical
Timur> memory. What happens to the physical memory that kmalloc
Timur> allocated? Why isn't it freed?
I asume it is used to generate page tables for the io memory it is
mapping, but I haven't looked at the code.
Jes
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This archive was generated by hypermail 2b29 : Sun Jul 23 2000 - 21:00:14 EST