Now that r0 is free we can keep the value of I/DMISS in r3 and not reload it before doing the tlbli/d. This saves us a few cycles in the fast path case.
Signed-off-by: Kumar Gala <[email protected]> --- There might be better uses of the free r0 to save more cycles in these code paths. If anyone has suggestions I'm willing to look at them. - k arch/powerpc/kernel/head_32.S | 51 +++++++++++++++++++--------------------- 1 files changed, 24 insertions(+), 27 deletions(-) diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index aafb469..b6c5955 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -498,25 +498,24 @@ InstructionTLBMiss: rlwinm. r2,r2,0,0,19 /* extract address of pte page */ beq- InstructionAddressInvalid /* return if no mapping */ rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */ - lwz r3,0(r2) /* get linux-style pte */ - andc. r1,r1,r3 /* check access & ~permission */ + lwz r0,0(r2) /* get linux-style pte */ + andc. r1,r1,r0 /* check access & ~permission */ bne- InstructionAddressInvalid /* return if access not permitted */ - ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */ + ori r0,r0,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */ /* * NOTE! We are assuming this is not an SMP system, otherwise * we would need to update the pte atomically with lwarx/stwcx. */ - stw r3,0(r2) /* update PTE (accessed bit) */ + stw r0,0(r2) /* update PTE (accessed bit) */ /* Convert linux-style PTE to low word of PPC-style PTE */ - rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */ - rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */ + rlwinm r1,r0,32-10,31,31 /* _PAGE_RW -> PP lsb */ + rlwinm r2,r0,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */ and r1,r1,r2 /* writable if _RW and _DIRTY */ - rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */ - rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */ + rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */ + rlwimi r0,r0,32-1,31,31 /* _PAGE_USER -> PP lsb */ ori r1,r1,0xe04 /* clear out reserved bits */ - andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */ + andc r1,r0,r1 /* PP = user? (rw&dirty? 2: 3): 0 */ mtspr SPRN_RPA,r1 - mfspr r3,SPRN_IMISS tlbli r3 mfspr r3,SPRN_SRR1 /* Need to restore CR0 */ mtcrf 0x80,r3 @@ -570,25 +569,24 @@ DataLoadTLBMiss: rlwinm. r2,r2,0,0,19 /* extract address of pte page */ beq- DataAddressInvalid /* return if no mapping */ rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */ - lwz r3,0(r2) /* get linux-style pte */ - andc. r1,r1,r3 /* check access & ~permission */ + lwz r0,0(r2) /* get linux-style pte */ + andc. r1,r1,r0 /* check access & ~permission */ bne- DataAddressInvalid /* return if access not permitted */ - ori r3,r3,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */ + ori r0,r0,_PAGE_ACCESSED /* set _PAGE_ACCESSED in pte */ /* * NOTE! We are assuming this is not an SMP system, otherwise * we would need to update the pte atomically with lwarx/stwcx. */ - stw r3,0(r2) /* update PTE (accessed bit) */ + stw r0,0(r2) /* update PTE (accessed bit) */ /* Convert linux-style PTE to low word of PPC-style PTE */ - rlwinm r1,r3,32-10,31,31 /* _PAGE_RW -> PP lsb */ - rlwinm r2,r3,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */ + rlwinm r1,r0,32-10,31,31 /* _PAGE_RW -> PP lsb */ + rlwinm r2,r0,32-7,31,31 /* _PAGE_DIRTY -> PP lsb */ and r1,r1,r2 /* writable if _RW and _DIRTY */ - rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */ - rlwimi r3,r3,32-1,31,31 /* _PAGE_USER -> PP lsb */ + rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */ + rlwimi r0,r0,32-1,31,31 /* _PAGE_USER -> PP lsb */ ori r1,r1,0xe04 /* clear out reserved bits */ - andc r1,r3,r1 /* PP = user? (rw&dirty? 2: 3): 0 */ + andc r1,r0,r1 /* PP = user? (rw&dirty? 2: 3): 0 */ mtspr SPRN_RPA,r1 - mfspr r3,SPRN_DMISS tlbld r3 mfspr r3,SPRN_SRR1 /* Need to restore CR0 */ mtcrf 0x80,r3 @@ -640,21 +638,20 @@ DataStoreTLBMiss: rlwinm. r2,r2,0,0,19 /* extract address of pte page */ beq- DataAddressInvalid /* return if no mapping */ rlwimi r2,r3,22,20,29 /* insert next 10 bits of address */ - lwz r3,0(r2) /* get linux-style pte */ - andc. r1,r1,r3 /* check access & ~permission */ + lwz r0,0(r2) /* get linux-style pte */ + andc. r1,r1,r0 /* check access & ~permission */ bne- DataAddressInvalid /* return if access not permitted */ - ori r3,r3,_PAGE_ACCESSED|_PAGE_DIRTY + ori r0,r0,_PAGE_ACCESSED|_PAGE_DIRTY /* * NOTE! We are assuming this is not an SMP system, otherwise * we would need to update the pte atomically with lwarx/stwcx. */ - stw r3,0(r2) /* update PTE (accessed/dirty bits) */ + stw r0,0(r2) /* update PTE (accessed/dirty bits) */ /* Convert linux-style PTE to low word of PPC-style PTE */ - rlwimi r3,r3,32-1,30,30 /* _PAGE_USER -> PP msb */ + rlwimi r0,r0,32-1,30,30 /* _PAGE_USER -> PP msb */ li r1,0xe05 /* clear out reserved bits & PP lsb */ - andc r1,r3,r1 /* PP = user? 2: 0 */ + andc r1,r0,r1 /* PP = user? 2: 0 */ mtspr SPRN_RPA,r1 - mfspr r3,SPRN_DMISS tlbld r3 mfspr r3,SPRN_SRR1 /* Need to restore CR0 */ mtcrf 0x80,r3 -- 1.5.6.6 _______________________________________________ Linuxppc-dev mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-dev
