Arm Community
Site
Search
User
Site
Search
User
Groups
Arm Research
DesignStart
Education Hub
Graphics and Gaming
High Performance Computing
Innovation
Multimedia
Open Source Software and Platforms
Physical
Processors
Security
System
Software Tools
TrustZone for Armv8-M
中文社区
Blog
Announcements
Artificial Intelligence
Automotive
Healthcare
HPC
Infrastructure
Innovation
Internet of Things
Machine Learning
Mobile
Smart Homes
Wearables
Forums
All developer forums
IP Product forums
Tool & Software forums
Support
Open a support case
Documentation
Downloads
Training
Arm Approved program
Arm Design Reviews
Community Help
More
Cancel
Developer Community
Tools and Software
Software Tools
Jump...
Cancel
Software Tools
Arm Development Studio forum
Control MMU for TrustZone
Tools, Software and IDEs blog
Forums
Videos & Files
Help
Jump...
Cancel
New
Replies
9 replies
Subscribers
126 subscribers
Views
5177 views
Users
0 members are here
Related
Control MMU for TrustZone
Offline
thiet pv
over 7 years ago
Note: This was originally posted on 20th July 2011 at http://forums.arm.com
Dear all,
I am a new bie about TrustZone. I arm learning the effect of TrustZone to MMU. I have some problems about the mechanism to manage secure/non-secure region by MMU.
Please help me to understand about them.
My dubious point described as below:
When translation virtual address to physical address, system will use TLB table. I know that, when have a miss occur on TLB, it will find physical page from page table.
From table index of virtual address and table base address, will have first-level descriptor, the first-level descriptor will be input for page table to get physical page table from page table
then fill it to TLB table.
If page table miss, it will find physical page form external memory (RAM) and fill it to page table with it's attribute.
So when cpu stay in secure world, and access to secure physical memory
How to know the address that cpu access include secure physical memory region or no-secure physical memory region?
How to partition the physical memory into secure and non-secure regions?
and if know secure attribute of secure region then
How to fill secure attribute to page table?
Please help me.
Thank you very much,
Parents
Offline
Martin Weidmann
over 7 years ago
Note: This was originally posted on 22nd July 2011 at
http://forums.arm.com
" think when the secure world makes a table walk that walk can be secure or non-secure, it depends on the physical page on page table mapped secure or non-secure."
When in the secure world, the walk of the l1 table will _always_ be done using secure accesses. Why? Well, because the processor only has a pointer to the L1 tables (TTBR0/1). It is the tables which define whether secure or non-secure accesses will be used for a particular address range. Therefore until it reads the table it has no way of knowing whether to use secure or non-secure accesses. So, while in the Secure world, the processor will always use secure accesses for the table walk.
Does this matter?
Well, first why would you want the page tables for the Secure world in memory accessible by the Normal world? This seems like a bit of flaw in your software!
Also, the processor does not know whether the target address accepts secure or non-secure (or both!) accesses. The target memory doesn't support the generated access type it will return an error, and the processor will take an abort. There is no auto-sensing system for the processor to discover the kind of access to use.
Cancel
Up
0
Down
Reply
Cancel
Reply
Offline
Martin Weidmann
over 7 years ago
Note: This was originally posted on 22nd July 2011 at
http://forums.arm.com
" think when the secure world makes a table walk that walk can be secure or non-secure, it depends on the physical page on page table mapped secure or non-secure."
When in the secure world, the walk of the l1 table will _always_ be done using secure accesses. Why? Well, because the processor only has a pointer to the L1 tables (TTBR0/1). It is the tables which define whether secure or non-secure accesses will be used for a particular address range. Therefore until it reads the table it has no way of knowing whether to use secure or non-secure accesses. So, while in the Secure world, the processor will always use secure accesses for the table walk.
Does this matter?
Well, first why would you want the page tables for the Secure world in memory accessible by the Normal world? This seems like a bit of flaw in your software!
Also, the processor does not know whether the target address accepts secure or non-secure (or both!) accesses. The target memory doesn't support the generated access type it will return an error, and the processor will take an abort. There is no auto-sensing system for the processor to discover the kind of access to use.
Cancel
Up
0
Down
Reply
Cancel
Children
No data
More questions in this forum
By title
By date
By reply count
By view count
By most asked
By votes
By quality
Descending
Ascending
All recent questions
Unread questions
Questions you've participated in
Questions you've asked
Unanswered questions
Answered questions
Questions with suggested answers
Questions with no replies
Suggested Answer
ARM development studio with ARM Juno r2 board
0
Juno Arm Development Platform
Arm Development Studio
Products
Arm Support
9042
views
2
replies
Latest
5 months ago
by
Ronan Synnott
Answered
"Unable to execute remote query (response code 503) " issue
0
8678
views
1
reply
Latest
5 months ago
by
Ronan Synnott
Answered
Where can I download DS-5 hardware firmware??
+1
8119
views
1
reply
Latest
5 months ago
by
Ronan Synnott
Not Answered
freeRTOS demo DS-5 ERROR(CMD360) when trying to debug
+1
13420
views
12
replies
Latest
6 months ago
by
tolc
Answered
ubuntu - How to uninstall Arm Development studio and all its requirements
0
Arm Development Studio
9069
views
1
reply
Latest
6 months ago
by
Jonathan Simmonds
<
>
View all questions in Arm Development Studio forum