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Flush x86 Processor TLB Buffer

Is it possible to get a list of translations (from virtual pages to physical pages) from TLB (translation transfer buffer, this is a special cache in the CPU). I mean modern x86 or x86_64; and I want to do this programmatically, rather than using JTAG and transferring all TLB entries.

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There is no such damper in the Linux kernel, there is a page from the Linux kernel about the cache and tlb: https://www.kernel.org/doc/Documentation/cachetlb.txt "Cache and TLB Flushing Under Linux". David C. Miller

In the 80386DX (and 80486 and, possibly, the "Embedded Pentium" was 10,000 MHz or the Embedded Pentium MMX 200-233 MHz "in 1998):

  • 1 - The book "MICROPROCESSORS: 8086/8088, 80186/80286, 80386/80486 AND THE PENT FAMILY", ISBN 9788120339422, 2010, p. 579

This was done through the TR6 TR7 test registers:

  • 2 - The book "Microprocessors and microcontrollers" from Godse & Godse, 2008 ISBN 9788184312973 page SA3-PA19: "3.2.7.3 Control registers" "Currently, only two test registers are defined (TR6-TR7) ... These registers are used for checking the translation viewing buffer (TLB) of the paging device. "
  • 3 "x86-Programmierung und-Betriebsarten (Teil 5). Die Testregister TR6 und TR7", deutsche register article: "Zur Prüfung des Translation-Lookaside-Buffers sind die zwei Testregister TR6 and TR7 vorhanden. Sie werden als Test-Command- Register (TR6) and Testdatenregister (TR7) bezeichnet. "
  • 4 Intel "Intel® Processor Family Design Guide for Embedded Pentium® Processors", Part "26 Specific Registers and Model Functions" page 8 "26.2.1.2 TLB Test Registers"

TR6 is a command register, a linear address is written to it. It can be used to write to a TLB or to read a string from a TLB. TR7 is data that must be written to or read from a TLB.

Wikipedia says in https://en.wikipedia.org/wiki/Test_register that reading TR6 / TR7 "generates an invalid operation code exception on any processor above 80486".

Mov tr6 / tr7 encoding is available only for privilege level 0: http://www.fermimn.gov.it/linux/quarta/x86/movrs.htm

0F 24 /r movl tr6/tr7,r32 12 Move (test register) to (register) movl %tr6,%ebx movl %tr7,%ebx 0F 26 /r movl r32,tr6/tr7 12 Move (register) to (test register) movl %ebx,%tr6 movl %ebx,%tr7
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You can get a list of VA-PA translations stored in TLBs, but you may have to use a processor emulator like qemu . You can download and install qemu from http://wiki.qemu.org/Main_Page. You can download the kernel, which is stored in a disk image (usually in qcow2 or in raw format) and run your application. You may need to tweak the code in qemu to print the contents of the TLB. Look at the tlb_* functions in qemu/exec.c You can add tlb_dump_function to print the contents of the TLB. As far as I know, this is the closest to the fact that you can dump the contents of the TLB.

PS: I began to answer this question, and then I realized that this is the year.

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