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PAT documentation - The Linux Kernel Archives
https://www.kernel.org/doc/Documentation/x86/pat.t ...
PAT is complementary to the MTRR settings which allows for setting of memory types over physical address ranges. ... In addition, step 2 internally tracks the region as UC or WC in memtype list in order to ensure no conflicting mapping.
11. PAT (Page Attribute Table) — The Linux Kernel documentation
https://www.kernel.org/doc/html/latest/x86/pat.htm ...
PAT is complementary to the MTRR settings which allows for setting of memory types over physical address ranges. ... WB/WC/UC-. (from existing alias). /dev/ mem mmap !SYNC flag no alias to this area and MTRR says WB, –, WB, WB.
PATting Linux - The Linux Kernel Archives
https://www.kernel.org/doc/ols/2008/ols2008v2-page ...
Jul 23, 2008 ... Uncacheable (UC). 1. Write Combining (WC). 2. Reserved. 3. Reserved. 4. Write Through (WT). 5. Write Protected (WP). 6. Write Back (WB). 7–0xFF. Reserved. Figure 4: Memory types that can be encoded with. MTRR.
MTRR (Memory Type Range Register) - Wikipedia
https://en.wikipedia.org/wiki/Memory_type_range_re ...
Memory type range registers (MTRRs) are a set of processor supplementary capabilities control registers that provide system software with control of how accesses to memory ranges by the CPU are cached. It uses a set of programmable ...
How MTRR registers implemented? - Stack Overflow
https://stackoverflow.com/questions/13297178/how-m ...
There are long rules for every mtrr memory type at pages 582-584, but rules for all 5 types (Uncacheable=UC, Write-Combining=WC, Write-Through=WT, Write- Protect=WP, Write-Back=WB) begins with: "Cache lookups are ...
Maintaining cache coherency - the archived page of xen.org, which ...
http://www-archive.xenproject.org/files/xensummitb ...
Guest OS uses no-fill mode before changing MTRR/PAT MSRs. Hardware doesn' t support ... memory types with physical address ranges in the system memory. WP. WP. WP. UC. UC. WP. UC. WB. WT. WC. UC. WB. WC. WP. WT. WC. UC. WP .
John McCalpin's blog » MTRR - UT WordPress Theme
https://sites.utexas.edu/jdm4372/tag/mtrr/
At least in the AMD Family 10h processors, this IORR function works, but due to some implementation issues in this particular use case it forces the region to the MTRR UC (uncached) type, which defeats my purpose in the exercise. I think that  ...
ee Section 11.11.1, “MTRR Feature Identification”).
https://xem.github.io/minix86/manual/intel-x86-and ...
contents of the IA32_MTRRCAP MSR. The functions of the flags and field in this register are as follows: Table 11-8. Memory Types That Can Be Encoded in MTRRs. Memory Type and Mnemonic. Encoding in MTRR. Uncacheable (UC). 00H.
Page 418
https://xem.github.io/minix86/manual/intel-x86-and ...
Strong Uncacheable (UC) —System memory locations are not cached. All reads and writes appear on the system bus and are executed in program order without reordering. No speculative memory accesses, page- table walks, or prefetches ...
Getting a handle on caching [LWN.net]
https://lwn.net/Articles/282250/
May 14, 2008 ... In general, when there is a conflict between the MTRR and PAT settings, the setting with the lower level of caching prevails. The one ... MTRRs can be setup in an overlapping mode where UC MTRRs trump WB MTRRs.