On Tue, 2014-12-16 at 16:03 +0100, Christophe Leroy wrote: > CR only needs to be preserved when checking if we are handling a kernel > address. > So we can preserve CR in a register: > - In ITLBMiss, check is done only when CONFIG_MODULES is defined. Otherwise we > don't need to do anything at all with CR. > - If CONFIG_8xx_CPU6 is defined, we have r3 available for saving CR > - Otherwise, we use r10, then we reload SRR0/MD_EPN into r10 when CR is > restored
I think the #ifdef CPU6 code makes for too much maintenance. Can you loose the #ifdef CPU6 and adjust code so it works for both cases? > > Signed-off-by: Christophe Leroy <[email protected]> > > --- > arch/powerpc/kernel/head_8xx.S | 53 > +++++++++++++++++++++++++++++------------- > 1 file changed, 37 insertions(+), 16 deletions(-) > > diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S > index c89aed9..a073918 100644 > --- a/arch/powerpc/kernel/head_8xx.S > +++ b/arch/powerpc/kernel/head_8xx.S > @@ -308,14 +308,10 @@ SystemCall: > #endif > > InstructionTLBMiss: > + EXCEPTION_PROLOG_0 > #ifdef CONFIG_8xx_CPU6 > mtspr SPRN_DAR, r3 > #endif > - EXCEPTION_PROLOG_0 > - mfcr r10 > - mtspr SPRN_SPRG_SCRATCH2, r10 > - mfspr r10, SPRN_SRR0/* Get effective address of fault */ > - DO_8xx_CPU15(r11, r10) > > /* If we are faulting a kernel address, we have to use the > * kernel page tables. > @@ -323,14 +319,33 @@ InstructionTLBMiss: > #ifdef CONFIG_MODULES > /* Only modules will cause ITLB Misses as we always > * pin the first 8MB of kernel memory */ > +#ifdef CONFIG_8xx_CPU6 > + mfspr r10, SPRN_SRR0/* Get effective address of fault */ > + DO_8xx_CPU15(r11, r10) > + mfcr r3 > andis. r11, r10, 0x8000/* Address >= 0x80000000 */ > +#else > + mfspr r11, SPRN_SRR0/* Get effective address of fault */ > + DO_8xx_CPU15(r10, r11) > + mfcr r10 > + andis. r11, r11, 0x8000/* Address >= 0x80000000 */ > #endif > mfspr r11, SPRN_M_TW/* Get level 1 table base address */ > -#ifdef CONFIG_MODULES > beq 3f > lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha > 3: > +#ifdef CONFIG_8xx_CPU6 > + mtcr r3 > +#else > + mtcr r10 > + mfspr r10, SPRN_SRR0/* Get effective address of fault */ > #endif > +#else /* CONFIG_MODULES */ > + mfspr r10, SPRN_SRR0/* Get effective address of fault */ > + DO_8xx_CPU15(r11, r10) > + mfspr r11, SPRN_M_TW/* Get level 1 table base address */ > +#endif /* CONFIG_MODULES */ > + > /* Insert level 1 index */ > rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << > 1, 29 > lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11)/* Get the level 1 > entry */ > @@ -362,29 +377,37 @@ InstructionTLBMiss: > mfspr r3, SPRN_DAR > mtspr SPRN_DAR, r11/* Tag DAR */ > #endif > - mfspr r10, SPRN_SPRG_SCRATCH2 > - mtcr r10 > EXCEPTION_EPILOG_0 > rfi > > . = 0x1200 > DataStoreTLBMiss: > -#ifdef CONFIG_8xx_CPU6 > - mtspr SPRN_DAR, r3 > -#endif > EXCEPTION_PROLOG_0 > - mfcr r10 > - mtspr SPRN_SPRG_SCRATCH2, r10 > - mfspr r10, SPRN_MD_EPN > > /* If we are faulting a kernel address, we have to use the > * kernel page tables. > */ > +#ifdef CONFIG_8xx_CPU6 > + mtspr SPRN_DAR, r3 > + mfcr r3 > + mfspr r10, SPRN_MD_EPN > andis. r11, r10, 0x8000 > +#else > + mfcr r10 > + mfspr r11, SPRN_MD_EPN > + andis. r11, r11, 0x8000 > +#endif > mfspr r11, SPRN_M_TW/* Get level 1 table base address */ > beq 3f > lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha > 3: > +#ifdef CONFIG_8xx_CPU6 > + mtcr r3 > +#else > + mtcr r10 > + mfspr r10, SPRN_MD_EPN > +#endif > + > /* Insert level 1 index */ > rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << > 1, 29 > lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11)/* Get the level 1 > entry */ > @@ -441,8 +464,6 @@ DataStoreTLBMiss: > mfspr r3, SPRN_DAR > #endif > mtspr SPRN_DAR, r11/* Tag DAR */ > - mfspr r10, SPRN_SPRG_SCRATCH2 > - mtcr r10 > EXCEPTION_EPILOG_0 > rfi > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
