On Thu, 2009-10-08 at 15:24 +0200, Joakim Tjernlund wrote: > +#define _PAGE_RW 0x0400 /* lsb PP bits, inverted in HW */ > +#define _PAGE_USER 0x0800 /* msb PP bits */ > > + /* r10=(r10&~_PAGE_PRESENT)|((r10&_PAGE_ACCESSED)>>5) */ > + rlwimi. r10, r10, 27, 31, 31 > + beq- cr0, 2f /* Can be removed, costs a ITLB Err */
Did you mean + /* r10=(r10&~_PAGE_PRESENT)|((r10&_PAGE_ACCESSED)>>4) */ + rlwimi. r10, r10, 28, 30, 31 + beq- cr0, 2f /* Can be removed, costs a ITLB Err */ Which would still be incorrect. You want -both- to be set, and your code will move on if -any- is set. Might want to add a ~ of the whole thing maybe and invert the condition ? I find it easier to just do li rX, requested_bits, and then, andc. rscratch, rX, rPTE > +#if 0 /* Dont' bother with PP lsb, bit 21 for now */ > + /* r10 = (r10 & ~0x0400) | ((r10 & _PAGE_EXEC) << 7) */ > + rlwimi r10, r10, 7, 21, 21 /* Set _PAGE_EXEC << 7 */ > +#endif I don't get that one. Don't bother with _PAGE_EXEC, there's no control of execute permission that works on 8xx. It's #if 0 anyway. You still need to massage the PP bits into place. I don't see that happening. As it is, your PTE contains for bit 20 and 21, which translates to: PTE: Translates to PP bits: RW: 0 USER: 0 00 supervisor RW (ok) RW: 0 USER: 1 01 supervisor RW user RO (WRONG) RW: 1 USER: 0 10 supervisor RW user RW (WRONG) RW: 1 USER: 1 11 supervisor RO user RO (WRONG) I would suggest you do the stuff I suggested initially with RW and USER being an "index" into a pre-cooked immediate value with all the encodings which also gives you the extended encoding for supervisor RO for free. > + /* Need to know if load/store -> force a TLB Error > + * by copying ACCESSED to PRESENT. > + */ > + /* r10=(r10&~_PAGE_PRESENT)|((r10&_PAGE_ACCESSED)>>5) */ > + rlwimi r10, r10, 27, 31, 31 That doesn't sound right, just like ITLB... you need to AND those two bits in a way or another, or basically test that they are both set (or neither is set) > +#if 0 /* Not yet */ > + /* Honour kernel RO, User NA */ > + andi. r11, r10, _PAGE_USER | _PAGE_RW > + bne- cr0, 5f > + ori r10,r10, 0x200 /* Extended encoding, bit 22 */ > #endif > - mfspr r11, SPRN_MD_TWC /* get the pte address again */ > - stw r10, 0(r11) > +5: xori r10, r10, _PAGE_RW /* invert RW bit */ Well, you are missing that xori from the ITLB miss I think. Also, that changes the table above to: PTE: Translates to PP bits: RW: 0 USER: 0 10 supervisor RW user RW (WRONG) RW: 0 USER: 1 11 supervisor RO user RO (ok) RW: 1 USER: 0 00 supervisor RW (ok) RW: 1 USER: 1 01 supervisor RW user RO (WRONG) So it's still not right :-) Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
