User Mapping: exiting right away.

[cs412050]

I am still working on User Mapping.
( My uservm.c is all covered with Print statement with
enable/disable switch variables, because too many print
makes kernel hang. )

As soon as kernel tris to start shell.exe, it exits right away.
I suspect Entry addr calculation (it prints 0x80001000).
My entryaddr is:

userContext->entryAddr = 0x80000000 + exeFormat->entryAddr;


And Also, I am confused with Virtual Memory and Logical address.
My understanding is:
1. VM is from 0 to 4G, and address space mapped to each user process.
2. Logical memory is from 0 to 2G, and upper part of user process
( from 2G to 4G )

If I am understanding right, I am confused when to use Vaddr, and
when to use logical addr. For formatting argument block,
we use 0x7ffff000, but page virtual address is 0xfffff000.
Can anyone clarify?

[William Francis Cladek]

Yeah, your understanding here is right. The trick is just figuring out when to use logical address or virtual address. A good guideline
is just to look at your project 2 implementation, as far as uservm.c is concerned, at least. For instance, entryAddr is a logical
address, so in your case you should not be adding 0x80000000. Same with arguments and stack, I think.

Hope this helps.

Will

Post by cs412050
I am still working on User Mapping.
( My uservm.c is all covered with Print statement with
enable/disable switch variables, because too many print
makes kernel hang. )
As soon as kernel tris to start shell.exe, it exits right away.
I suspect Entry addr calculation (it prints 0x80001000).
userContext->entryAddr = 0x80000000 + exeFormat->entryAddr;
And Also, I am confused with Virtual Memory and Logical address.
1. VM is from 0 to 4G, and address space mapped to each user process.
2. Logical memory is from 0 to 2G, and upper part of user process
( from 2G to 4G )
If I am understanding right, I am confused when to use Vaddr, and
when to use logical addr. For formatting argument block,
we use 0x7ffff000, but page virtual address is 0xfffff000.
Can anyone clarify?

[Raymond Chung]

Thank you, Will.
That was it. Now I got user mapping done.
I appreciate and Good luck to you.


William Francis Cladek <***@predict.eng.umd.edu> wrote: