Why is the page size of Linux (x86) 4 KB, how is that calculated?

by

The default page size is fixed by what the MMU (memory management unit) of the CPU supports. In 32-bit protected mode x86 supports two kinds of pages:

  • normal ones, 4 KiB
  • huge ones, 4 MiB

Not all x86 processors support large pages. One needs to have a CPU with Page Size Extension (PSE) capabilities. This excludes pre-Pentium processors. Virtually all current-generation x86 CPUs implements it.

4 KiB is widely popuplar page granularity in other architectures too. One could argue that this size comes from the division of a 32-bit virutal address into two 10-bit indexes in page directories/tables and the remaining 12 bits give the 4 KiB page size.

More Related Contents:

  1. Assembling 32-bit binaries on a 64-bit system (GNU toolchain)
  2. How does x86 paging work?
  3. How to invoke a system call via syscall or sysenter in inline assembly?
  4. How to print a number in assembly NASM?
  5. How are the fs/gs registers used in Linux AMD64?
  6. What is better “int 0x80” or “syscall” in 32-bit code on Linux?
  7. Hello, world in assembly language with Linux system calls?
  8. Minimal executable size now 10x larger after linking than 2 years ago, for tiny programs?
  9. “No such file or directory” error when executing a binary
  10. Assembly compiled executable using INT 0x80 on Ubuntu on Windows Subsystem for Linux doesn’t produce output
  11. How do I disassemble raw 16-bit x86 machine code?
  12. How to print a character in Linux x86 NASM?
  13. Using gdb to single-step assembly code outside specified executable causes error “cannot find bounds of current function”
  14. Why do virtual memory addresses for linux binaries start at 0x8048000?
  15. Why can’t I mmap(MAP_FIXED) the highest virtual page in a 32-bit Linux process on a 64-bit kernel?
  16. Is garbage allowed in high bits of parameter and return value registers in x86-64 SysV ABI?
  17. Assembly segmentation fault after making a system call, at the end of my code
  18. How to calculate time for an asm delay loop on x86 linux?
  19. Is there a way to get gcc to output raw binary?
  20. Why Linux/gnu linker chose address 0x400000?
  21. Trying to understand gcc’s complicated stack-alignment at the top of main that copies the return address
  22. How to disassemble, modify and then reassemble a Linux executable?
  23. What is the default register state when program launches (asm, linux)?
  24. get string length in inline GNU Assembler
  25. Running 32 bit assembly code on a 64 bit Linux & 64 bit Processor : Explain the anomaly
  26. /usr/bin/ld: skipping incompatible foo.so when searching for foo
  27. Hardware cache events and perf
  28. Using software floating point on x86 linux
  29. Responsibility of stack alignment in 32-bit x86 assembly
  30. Write system call won’t print characters from a register

Leave a Comment