rust-osdev / rust-osdev/bootloader
PhysFrames mapped multiple times?
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Description
Yeah, stuff gets mapped multiple times. Here is my log output [from an isa-debugcon]:
; STUFF HERE
MAP @ PhysFrame[4KiB](0x5f8000) to Page[4KiB](0xf001f7000)
Now mapping Seg
MAP @ PhysFrame[4KiB](0x5f8000) to Page[4KiB](0xf001f7000)
panicked at 'kernel mapping failed: Mapping(PageAlreadyMapped(PhysFrame[4KiB](0x5f8000)))', src/main.rs:268:6
And it just hangs. So... It seems that sections do NOT have to be 4k-aligned in ELFs. The culprit in my case was .got. Forcing it to stay aligned fixed my problem. But, this should just work and not require custom linker scripts.
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Research direction
Start at src/main.rs:268 and reproduce the isa-debugcon log showing the same PhysFrame mapped twice. Inspect the ELF section and linker-script handling around the .got section and compare the requested mappings. Done means ELF sections that are not 4 KiB-aligned no longer cause duplicate mappings or a Mapping(PageAlreadyMapped) panic.
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Assessment
- Tech stack
- rust
- Domain
- operating-systems
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100