Excerpts from Christophe Leroy's message of March 9, 2021 10:09 pm:
> book3e/64 is the last one calling __bad_page_fault()
> from assembly.
>
> Save non volatile registers before calling do_page_fault()
> and modify do_page_fault() to call __bad_page_fault()
> for all platforms.
>
> Then it can be refactored by the call of bad_page_fault()
> which avoids the duplication of the exception table search.
This can go in with the 64e change after your series. I think it should
be ready for the next merge window as well.
Thanks,
Nick
>
> Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
> ---
> arch/powerpc/kernel/exceptions-64e.S | 8 +-------
> arch/powerpc/mm/fault.c | 17 ++++-------------
> 2 files changed, 5 insertions(+), 20 deletions(-)
>
> diff --git a/arch/powerpc/kernel/exceptions-64e.S
> b/arch/powerpc/kernel/exceptions-64e.S
> index e8eb9992a270..b60f89078a3f 100644
> --- a/arch/powerpc/kernel/exceptions-64e.S
> +++ b/arch/powerpc/kernel/exceptions-64e.S
> @@ -1010,15 +1010,9 @@ storage_fault_common:
> addi r3,r1,STACK_FRAME_OVERHEAD
> ld r14,PACA_EXGEN+EX_R14(r13)
> ld r15,PACA_EXGEN+EX_R15(r13)
> + bl save_nvgprs
> bl do_page_fault
> - cmpdi r3,0
> - bne- 1f
> b ret_from_except_lite
> -1: bl save_nvgprs
> - mr r4,r3
> - addi r3,r1,STACK_FRAME_OVERHEAD
> - bl __bad_page_fault
> - b ret_from_except
>
> /*
> * Alignment exception doesn't fit entirely in the 0x100 bytes so it
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> index 2e54bac99a22..7bcff3fca110 100644
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -541,24 +541,15 @@ NOKPROBE_SYMBOL(___do_page_fault);
>
> static long __do_page_fault(struct pt_regs *regs)
> {
> - const struct exception_table_entry *entry;
> long err;
>
> err = ___do_page_fault(regs, regs->dar, regs->dsisr);
> if (likely(!err))
> - return err;
> -
> - entry = search_exception_tables(regs->nip);
> - if (likely(entry)) {
> - instruction_pointer_set(regs, extable_fixup(entry));
> return 0;
> - } else if (!IS_ENABLED(CONFIG_PPC_BOOK3E_64)) {
> - __bad_page_fault(regs, err);
> - return 0;
> - } else {
> - /* 32 and 64e handle the bad page fault in asm */
> - return err;
> - }
> +
> + bad_page_fault(regs, err);
> +
> + return 0;
> }
> NOKPROBE_SYMBOL(__do_page_fault);
>
> --
> 2.25.0
>
>
