DOS ain't dead

some modern UEFI/CSM leaves CR0.WP set at boot (Developers)

posted by Japheth , Germany (South), 23.01.2024, 13:24
(edited by Japheth on 23.01.2024, 13:56)

> Not sure if this can cause issues also under DOS with JEMM/DPMI,

Not with Jemm or Hdpmi. I'm aware of this possibility since at least 10 years and ensured that it's no problem.

That doesn't mean that it's irrelevant. The Deb386 ring 0 debugger may cause page faults if the WP bit is set and the G(o) cmd is used with a breakpoint argument. That's why the little tool ResWP.exe is supplied with the debugger - guess what it does! Most DPMI host won't set page table attributes to R/O, but HX's DPMILD32 does so for code sections.

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MS-DOS forever!

Complete thread:

• some modern UEFI/CSM leaves CR0.WP set at boot - RayeR, 23.01.2024, 08:10 (Developers)
  • some modern UEFI/CSM leaves CR0.WP set at boot - Japheth, 23.01.2024, 13:24
    • some modern UEFI/CSM leaves CR0.WP set at boot - RayeR, 23.01.2024, 18:44
    • some modern UEFI/CSM leaves CR0.WP set at boot - Rugxulo, 23.01.2024, 23:41
      • some modern UEFI/CSM leaves CR0.WP set at boot - Japheth, 24.01.2024, 07:23