rv32i: pmp: Remove power of two allignment constraint #1805
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The TOR PMP implementation (the one we are using) does not require a power of two size allignment so let's remove it to save space. Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
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Are you worried we would have a size less then the pointer size, or not aligned to the pointer size? The TOR PMP still needs to be 4byte aligned as we shift (>> 2) when writing to a register so we should be ok. |
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I'm both not actually worried and worried that it won't be aligned to pointer size. Several other parts of the kernel assume that region boundaries are aligned to at least pointer width (see the recent series clippy / cast stuff). On the one hand, I really don't see it as likely for an MPU region to have granularity finer than pointer width; on the other hand, we c/would start having alignment issues if anything ever did that currently. |
bradjc
approved these changes
Apr 29, 2020
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Pull Request Overview
The TOR PMP implementation (the one we are using) does not require a
power of two size allignment so let's remove it to save space.
Testing Strategy
Running OpenTitan in QEMU with PMP enabled.
TODO or Help Wanted
Documentation Updated
/docs, or no updates are required.Formatting
make formatall.