rust-embedded / rust-embedded/aarch32

Data abort test doesn't work on ARMv4

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Dominant language
Rust
Stars
66
Forks
25
Avg merge
4d 6h
Merged PRs (30d)
4

Description

Our data abort exception test relies on an unaligned load triggering a data abort. This does not happen on ARM7TDMI.

A more reliable way to trigger a data abort on that processor is to read a value from an address that is reserved. e.g.

core::arch::naked_asm!(
	"ldr     r0, =0xC0000000",
	"ldr     r0, [r0]",
	"bx      lr",
);

The address 0xC000_0000 is not a valid address on the LPC2138 microcontroller I tested with because it's in the reserved range.

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Locate the data abort exception test and its ARMv4 or ARM7TDMI setup. Replace the unaligned-load trigger with the reserved-address read described in the issue, then run the existing exception test on the affected target and confirm that it reliably produces a data abort.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
embedded-iot, testing-qa
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
68/100

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