Skip to content
This repository was archived by the owner on Jun 7, 2023. It is now read-only.

feat: use vectoring to jump straight to interruptN #11

Merged
merged 5 commits into from
Jun 7, 2023
Merged

feat: use vectoring to jump straight to interruptN #11

Show file tree
Hide file tree
Changes from 4 commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
9b77193
feat: use vectoring to jump straight to interruptN
sethp May 19, 2023
39cb39a
fix(ci): use nightly clippy
sethp May 19, 2023
0314d66
Revert "feat: use vectoring to jump straight to interruptN"
sethp May 26, 2023
35c3a4a
feat: allow vectoring per-slot overrides
sethp May 26, 2023
d5e5cc9
fix: restore per-slot handlers
sethp May 28, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion .github/workflows/ci.yml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ jobs:
- uses: actions/checkout@v3
- uses: dtolnay/rust-toolchain@v1
with:
toolchain: stable
toolchain: nightly
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is nightly really still needed here?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Oh, huh: looks like it's not for clippy (this part). I lean towards keeping it, to line it up with the rustfmt and check builds that both use nightly.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I hadn't looked, in that case, i agree.

components: clippy
- uses: Swatinem/rust-cache@v2

Expand Down
77 changes: 70 additions & 7 deletions src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -426,15 +426,78 @@ _abs_start:
.cfi_endproc

/*
Trap entry point (_start_trap)
Trap entry points (_start_trap, _start_trapN for N in 1..=31)

Saves caller saved registers ra, t0..6, a0..7, calls _start_trap_rust,
restores caller saved registers and then returns.
The default implementation saves all registers to the stack and calls
_start_trap_rust, then restores all saved registers before `mret`
*/
.section .trap, "ax"
.global default_start_trap

default_start_trap:
.weak _start_trap
.weak _start_trap1
.weak _start_trap2
.weak _start_trap3
.weak _start_trap4
.weak _start_trap5
.weak _start_trap6
.weak _start_trap7
.weak _start_trap8
.weak _start_trap9
.weak _start_trap10
.weak _start_trap11
.weak _start_trap12
.weak _start_trap13
.weak _start_trap14
.weak _start_trap15
.weak _start_trap16
.weak _start_trap17
.weak _start_trap18
.weak _start_trap19
.weak _start_trap20
.weak _start_trap21
.weak _start_trap22
.weak _start_trap23
.weak _start_trap24
.weak _start_trap25
.weak _start_trap26
.weak _start_trap27
.weak _start_trap28
.weak _start_trap29
.weak _start_trap30
.weak _start_trap31

_start_trap1:
_start_trap2:
_start_trap3:
_start_trap4:
_start_trap5:
_start_trap6:
_start_trap7:
_start_trap8:
_start_trap9:
_start_trap10:
_start_trap11:
_start_trap12:
_start_trap13:
_start_trap14:
_start_trap15:
_start_trap16:
_start_trap17:
_start_trap18:
_start_trap19:
_start_trap20:
_start_trap21:
_start_trap22:
_start_trap23:
_start_trap24:
_start_trap25:
_start_trap26:
_start_trap27:
_start_trap28:
_start_trap29:
_start_trap30:
_start_trap31:

_start_trap:
addi sp, sp, -40*4

sw ra, 0*4(sp)
Expand Down Expand Up @@ -534,7 +597,7 @@ abort:
*/

.section .trap, "ax"
.global _vector_table
.weak _vector_table
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change
.weak _vector_table
.weak _vector_table
.type _vector_table, @function
.option push
.balign 0x100
.option norelax
.option norvc
_vector_table:
j _start_trap
j _start_trap1
j _start_trap2
j _start_trap3
j _start_trap4
j _start_trap5
j _start_trap6
j _start_trap7
j _start_trap8
j _start_trap9
j _start_trap10
j _start_trap11
j _start_trap12
j _start_trap13
j _start_trap14
j _start_trap15
j _start_trap16
j _start_trap17
j _start_trap18
j _start_trap19
j _start_trap20
j _start_trap21
j _start_trap22
j _start_trap23
j _start_trap24
j _start_trap25
j _start_trap26
j _start_trap27
j _start_trap28
j _start_trap29
j _start_trap30
j _start_trap31

My suggestion is replacing the default vector table with one hooking the weakly linked handlers. This should come at no cost (since by default they just point to the generic handler anyway) and gives a much more powerful default implementation.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I wasn't able to tame the review functionality here, so the suggestion is just a gist.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Oh yeah, excellent point! I'll fix that right up.

.type _vector_table, @function

.option push
Expand Down