Re: [PATCH v2 3/7] riscv: convert bottom half of exception handling to C

[Deepak Gupta]

On Sun, Jul 21, 2024 at 01:12:28AM +0800, Jisheng Zhang wrote:
> For readability, maintainability and future scalability, convert the
> bottom half of the exception handling to C.
>
> Mostly the assembly code is converted to C in a relatively
> straightforward manner.
>
> However, there are two modifications I need to mention:
>
> 1. the cause I.E the CSR_CAUSE value is passed to do_traps() via. 2nd
> param, do_traps() doesn't get it from pt_regs because this way an extra
> memory load is needed, the exception handling sits in hot code path,
> every instruction matters.
>
> 2.To cope with SIFIVE_CIP_453 errata, it looks like we don't need
> alternative mechanism any more after the asm->c conversion. Just
> replace the excp_vect_table two entries.
>
> Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
> ---
> arch/riscv/errata/sifive/errata.c       | 25 ++++++++---
> arch/riscv/include/asm/asm-prototypes.h |  1 +
> arch/riscv/include/asm/errata_list.h    |  5 +--
> arch/riscv/kernel/entry.S               | 57 +------------------------
> arch/riscv/kernel/traps.c               | 37 ++++++++++++++++
> 5 files changed, 61 insertions(+), 64 deletions(-)
Sorry for noticing it so late. And thanks to Bjorn for pointing it out.
lgtm.

Reviewed-by: Deepak Gupta <debug@xxxxxxxxxxxx>