; Get the PTE entry: The idea is
; (1) x = addr >> PAGE_SHIFT -> masks page-off bits from @fault-addr
; (2) y = x & (PTRS_PER_PTE - 1) -> to get index
- ; (3) z = pgtbl[y]
- ; To avoid the multiply by in end, we do the -2, <<2 below
+ ; (3) z = (pgtbl + y * 4)
- lsr r0, r2, (PAGE_SHIFT - 2)
- and r0, r0, ( (PTRS_PER_PTE - 1) << 2)
- ld.aw r0, [r1, r0] ; get PTE and PTE ptr for fault addr
+#define PTE_SIZE_LOG 2 /* 4 == 2 ^ 2 */
+
+ ; multiply in step (3) above avoided by shifting lesser in step (1)
+ lsr r0, r2, ( PAGE_SHIFT - PTE_SIZE_LOG )
+ and r0, r0, ( (PTRS_PER_PTE - 1) << PTE_SIZE_LOG )
+ ld.aw r0, [r1, r0] ; r0: PTE
+ ; r1: PTE ptr
2:
; IN: r0 = PTE, r1 = ptr to PTE
.macro CONV_PTE_TO_TLB
- and r3, r0, PTE_BITS_RWX ; r w x
- lsl r2, r3, 3 ; r w x 0 0 0 (GLOBAL, kernel only)
+ and r3, r0, PTE_BITS_RWX ; r w x
+ lsl r2, r3, 3 ; Kr Kw Kx 0 0 0 (GLOBAL, kernel only)
and.f 0, r0, _PAGE_GLOBAL
- or.z r2, r2, r3 ; r w x r w x (!GLOBAL, user page)
+ or.z r2, r2, r3 ; Kr Kw Kx Ur Uw Ux (!GLOBAL, user page)
and r3, r0, PTE_BITS_NON_RWX_IN_PD1 ; Extract PFN+cache bits from PTE
or r3, r3, r2
- sr r3, [ARC_REG_TLBPD1] ; these go in PD1
+ sr r3, [ARC_REG_TLBPD1] ; paddr[31..13] | Kr Kw Kx Ur Uw Ux | C
and r2, r0, PTE_BITS_IN_PD0 ; Extract other PTE flags: (V)alid, (G)lb