This is a good point though I'd argue that the spec isn't all that readable for some important things.
For example the description of exception handling is sprinkled between the CSR definitions of the CSRs involved. There's no section that just lays out the exception model.
True, but the entire "Machine-Level CSRs" section is under 30 pages, and the parts you need to understand what happens when an exception happens is basically parts of the `mstatus` description specifically "3.1.6.1 Privilege and Global Interrupt-Enable Stack in mstatus register" (one page), the section on `MPRV` (less than a page), the sections on `mtvec`, `medeleg`, `mideleg`, `mip`, `mie` (five contiguous pages), the sections on `mscratch`, `mepc`, `mcause`, `mtval` (about five contiguous pages), and the sections on the `ecall, `ebreak`, `mret`, `sret` instructions (about a page), and the sections on what happens at RESET and NMIs (just over a page).
So that's about 14 pages. This doesn't seem onerous to me, and counts as "in one place". It's about half of the entire M mode spec, which you might as well simply read in its entirety (two or three times), not try to cherry-pick.
I mean ... you don't want a solid 14 pages of description with no section heading at all, do you?
Maybe you want a single page that gives a 30,000 foot view. That would be possible, but it would inevitably have to leave out a lot and you'll need to read the detailed descriptions anyway.
For example the description of exception handling is sprinkled between the CSR definitions of the CSRs involved. There's no section that just lays out the exception model.