Hi Daniel,
The convention is:
- paddr_t is used for physical addresses.
- pptr_t is a virtual address "in the kernel window" that refers to a kernel
object (e.g. page directory or endpoint). Users don't have access to any pptr_t
addresses (but might have a capability to do operations on it, via syscalls).
- vptr_t is a virtual address in user-space but not in the kernel window.
Usually, this is calculated when doing operations on user-level address space
(i.e. mapping a page at vptr_t, or invalidate a "user-level" Cache/TLB entry).
Hope that helps.
On 01/04/17 06:37, Daniel (Xiaolong) Wang wrote:
> Hi all,
>
> I have a probably a dumb question that need some clarification. I was
> reading the kernel source code and I’m little bit confused with the
> three data type:
>
> *paddr_t*, *pptr_t*, *vptr_t *and the following three data struct
> related to them.
> *
> *
> *typedef struct region {*
> * pptr_t start;*
> * pptr_t end;*
> *} region_t;*
> *
> *
> *typedef struct p_region {*
> * paddr_t start;*
> * paddr_t end;*
> *} p_region_t;*
> *
> *
> *typedef struct v_region {*
> * vptr_t start;*
> * vptr_t end;*
> *} v_region_t;*
>
> Based on how those are being used I assume the *paddr_t *and* p_region
> *are data struct for physical address, *vptr_t* and *v_region *are for
> virtual address. According to the following functions seem that the
> translation between physical address to pptr_r is by adding/subtracting
> a offset. But I’m confused with the *pptr_t* and region I wonder what
> are those for? Tank you very much!
>
> /static inline void* CONST/
> /ptrFromPAddr(paddr_t paddr)/
> /{/
> / return (void*)(paddr + physMappingOffset);/
> /}/
> /
> /
> /static inline paddr_t CONST/
> /addrFromPPtr(void* pptr)/
> /{/
> / return (paddr_t)pptr - physMappingOffset;/
> /}/
> /
> /
> /static inline region_t CONST/
> /paddr_to_pptr_reg(p_region_t p_reg)/
> /{/
> / return (region_t) {/
> / p_reg.start + physMappingOffset, p_reg.end + physMappingOffset/
> / };/
> /}/
> /
> /
> /static inline p_region_t CONST/
> /pptr_to_paddr_reg(region_t reg)/
> /{/
> / return (p_region_t) {/
> / reg.start - physMappingOffset, reg.end - physMappingOffset/
> / };/
> /}/
>
> Thanks
> -Dan
>
>
>
>
> _______________________________________________
> Devel mailing list
> [email protected]
> https://sel4.systems/lists/listinfo/devel
>
--
Hesham Almatary
Kernel Engineer
DATA61 | CSIRO
E: [email protected]
www.data61.csiro.au
_______________________________________________
Devel mailing list
[email protected]
https://sel4.systems/lists/listinfo/devel
