Excerpts from Christophe Leroy's message of January 27, 2021 4:38 pm: > > > Le 15/01/2021 à 17:49, Nicholas Piggin a écrit : >> Make mm fault handlers all just take the pt_regs * argument and load >> DAR/DSISR from that. Make those that return a value return long. >> >> This is done to make the function signatures match other handlers, which >> will help with a future patch to add wrappers. Explicit arguments could >> be added for performance but that would require more wrapper macro >> variants. >> >> Signed-off-by: Nicholas Piggin <npig...@gmail.com> >> --- >> arch/powerpc/include/asm/asm-prototypes.h | 4 ++-- >> arch/powerpc/include/asm/book3s/64/mmu-hash.h | 2 +- >> arch/powerpc/include/asm/bug.h | 2 +- >> arch/powerpc/kernel/entry_32.S | 7 +------ >> arch/powerpc/kernel/exceptions-64e.S | 2 -- >> arch/powerpc/kernel/exceptions-64s.S | 17 ++++------------- >> arch/powerpc/kernel/head_40x.S | 10 +++++----- >> arch/powerpc/kernel/head_8xx.S | 6 +++--- >> arch/powerpc/kernel/head_book3s_32.S | 5 ++--- >> arch/powerpc/kernel/head_booke.h | 4 +--- >> arch/powerpc/mm/book3s64/hash_utils.c | 8 +++++--- >> arch/powerpc/mm/book3s64/slb.c | 11 +++++++---- >> arch/powerpc/mm/fault.c | 5 ++--- >> 13 files changed, 34 insertions(+), 49 deletions(-) >> > >> diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S >> index 238eacfda7b0..d6ea3f2d6cc0 100644 >> --- a/arch/powerpc/kernel/entry_32.S >> +++ b/arch/powerpc/kernel/entry_32.S >> @@ -276,8 +276,7 @@ reenable_mmu: >> * We save a bunch of GPRs, >> * r3 can be different from GPR3(r1) at this point, r9 and r11 >> * contains the old MSR and handler address respectively, >> - * r4 & r5 can contain page fault arguments that need to be passed >> - * along as well. r0, r6-r8, r12, CCR, CTR, XER etc... are left >> + * r0, r4-r8, r12, CCR, CTR, XER etc... are left >> * clobbered as they aren't useful past this point. >> */ >> >> @@ -285,15 +284,11 @@ reenable_mmu: >> stw r9,8(r1) >> stw r11,12(r1) >> stw r3,16(r1) > > As all functions only take 'regs' as input parameter, maybe we can avoid > saving 'r3' by > recalculating it from r1 after the call with 'addi > r3,r1,STACK_FRAME_OVERHEAD' ?
It seems like it. All functions have regs as first parameter already don't they? So this change could be done before this patch as well. > >> - stw r4,20(r1) >> - stw r5,24(r1) > > Patch 6 needs to go before this change. Probably the easiest would be to > apply patch 6 before patch > 5. Or this change needs to go after. Hmm okay thanks for finding that. Thanks, Nick
