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Diffstat (limited to 'arch/sparc64/kernel/dtlb_backend.S')
| -rw-r--r-- | arch/sparc64/kernel/dtlb_backend.S | 170 |
1 files changed, 0 insertions, 170 deletions
diff --git a/arch/sparc64/kernel/dtlb_backend.S b/arch/sparc64/kernel/dtlb_backend.S deleted file mode 100644 index acc889a..0000000 --- a/arch/sparc64/kernel/dtlb_backend.S +++ /dev/null @@ -1,170 +0,0 @@ -/* $Id: dtlb_backend.S,v 1.16 2001/10/09 04:02:11 davem Exp $ - * dtlb_backend.S: Back end to DTLB miss replacement strategy. - * This is included directly into the trap table. - * - * Copyright (C) 1996,1998 David S. Miller (davem@redhat.com) - * Copyright (C) 1997,1998 Jakub Jelinek (jj@ultra.linux.cz) - */ - -#include <asm/pgtable.h> -#include <asm/mmu.h> - -#define VALID_SZ_BITS (_PAGE_VALID | _PAGE_SZBITS) - -#define VPTE_BITS (_PAGE_CP | _PAGE_CV | _PAGE_P ) -#define VPTE_SHIFT (PAGE_SHIFT - 3) - -/* Ways we can get here: - * - * 1) Nucleus loads and stores to/from PA-->VA direct mappings at tl>1. - * 2) Nucleus loads and stores to/from user/kernel window save areas. - * 3) VPTE misses from dtlb_base and itlb_base. - * - * We need to extract out the PMD and PGDIR indexes from the - * linear virtual page table access address. The PTE index - * is at the bottom, but we are not concerned with it. Bits - * 0 to 2 are clear since each PTE is 8 bytes in size. Each - * PMD and PGDIR entry are 4 bytes in size. Thus, this - * address looks something like: - * - * |---------------------------------------------------------------| - * | ... | PGDIR index | PMD index | PTE index | | - * |---------------------------------------------------------------| - * 63 F E D C B A 3 2 0 <- bit nr - * - * The variable bits above are defined as: - * A --> 3 + (PAGE_SHIFT - log2(8)) - * --> 3 + (PAGE_SHIFT - 3) - 1 - * (ie. this is "bit 3" + PAGE_SIZE - size of PTE entry in bits - 1) - * B --> A + 1 - * C --> B + (PAGE_SHIFT - log2(4)) - * --> B + (PAGE_SHIFT - 2) - 1 - * (ie. this is "bit B" + PAGE_SIZE - size of PMD entry in bits - 1) - * D --> C + 1 - * E --> D + (PAGE_SHIFT - log2(4)) - * --> D + (PAGE_SHIFT - 2) - 1 - * (ie. this is "bit D" + PAGE_SIZE - size of PGDIR entry in bits - 1) - * F --> E + 1 - * - * (Note how "B" always evalutes to PAGE_SHIFT, all the other constants - * cancel out.) - * - * For 8K PAGE_SIZE (thus, PAGE_SHIFT of 13) the bit numbers are: - * A --> 12 - * B --> 13 - * C --> 23 - * D --> 24 - * E --> 34 - * F --> 35 - * - * For 64K PAGE_SIZE (thus, PAGE_SHIFT of 16) the bit numbers are: - * A --> 15 - * B --> 16 - * C --> 29 - * D --> 30 - * E --> 43 - * F --> 44 - * - * Because bits both above and below each PGDIR and PMD index need to - * be masked out, and the index can be as long as 14 bits (when using a - * 64K PAGE_SIZE, and thus a PAGE_SHIFT of 16), we need 3 instructions - * to extract each index out. - * - * Shifts do not pair very well on UltraSPARC-I, II, IIi, and IIe, so - * we try to avoid using them for the entire operation. We could setup - * a mask anywhere from bit 31 down to bit 10 using the sethi instruction. - * - * We need a mask covering bits B --> C and one covering D --> E. - * For 8K PAGE_SIZE these masks are 0x00ffe000 and 0x7ff000000. - * For 64K PAGE_SIZE these masks are 0x3fff0000 and 0xfffc0000000. - * The second in each set cannot be loaded with a single sethi - * instruction, because the upper bits are past bit 32. We would - * need to use a sethi + a shift. - * - * For the time being, we use 2 shifts and a simple "and" mask. - * We shift left to clear the bits above the index, we shift down - * to clear the bits below the index (sans the log2(4 or 8) bits) - * and a mask to clear the log2(4 or 8) bits. We need therefore - * define 4 shift counts, all of which are relative to PAGE_SHIFT. - * - * Although unsupportable for other reasons, this does mean that - * 512K and 4MB page sizes would be generaally supported by the - * kernel. (ELF binaries would break with > 64K PAGE_SIZE since - * the sections are only aligned that strongly). - * - * The operations performed for extraction are thus: - * - * ((X << FOO_SHIFT_LEFT) >> FOO_SHIFT_RIGHT) & ~0x3 - * - */ - -#define A (3 + (PAGE_SHIFT - 3) - 1) -#define B (A + 1) -#define C (B + (PAGE_SHIFT - 2) - 1) -#define D (C + 1) -#define E (D + (PAGE_SHIFT - 2) - 1) -#define F (E + 1) - -#define PMD_SHIFT_LEFT (64 - D) -#define PMD_SHIFT_RIGHT (64 - (D - B) - 2) -#define PGDIR_SHIFT_LEFT (64 - F) -#define PGDIR_SHIFT_RIGHT (64 - (F - D) - 2) -#define LOW_MASK_BITS 0x3 - -/* TLB1 ** ICACHE line 1: tl1 DTLB and quick VPTE miss */ - ldxa [%g1 + %g1] ASI_DMMU, %g4 ! Get TAG_ACCESS - add %g3, %g3, %g5 ! Compute VPTE base - cmp %g4, %g5 ! VPTE miss? - bgeu,pt %xcc, 1f ! Continue here - andcc %g4, TAG_CONTEXT_BITS, %g5 ! tl0 miss Nucleus test - ba,a,pt %xcc, from_tl1_trap ! Fall to tl0 miss -1: sllx %g6, VPTE_SHIFT, %g4 ! Position TAG_ACCESS - or %g4, %g5, %g4 ! Prepare TAG_ACCESS - -/* TLB1 ** ICACHE line 2: Quick VPTE miss */ - mov TSB_REG, %g1 ! Grab TSB reg - ldxa [%g1] ASI_DMMU, %g5 ! Doing PGD caching? - sllx %g6, PMD_SHIFT_LEFT, %g1 ! Position PMD offset - be,pn %xcc, sparc64_vpte_nucleus ! Is it from Nucleus? - srlx %g1, PMD_SHIFT_RIGHT, %g1 ! Mask PMD offset bits - brnz,pt %g5, sparc64_vpte_continue ! Yep, go like smoke - andn %g1, LOW_MASK_BITS, %g1 ! Final PMD mask - sllx %g6, PGDIR_SHIFT_LEFT, %g5 ! Position PGD offset - -/* TLB1 ** ICACHE line 3: Quick VPTE miss */ - srlx %g5, PGDIR_SHIFT_RIGHT, %g5 ! Mask PGD offset bits - andn %g5, LOW_MASK_BITS, %g5 ! Final PGD mask - lduwa [%g7 + %g5] ASI_PHYS_USE_EC, %g5! Load PGD - brz,pn %g5, vpte_noent ! Valid? -sparc64_kpte_continue: - sllx %g5, 11, %g5 ! Shift into place -sparc64_vpte_continue: - lduwa [%g5 + %g1] ASI_PHYS_USE_EC, %g5! Load PMD - sllx %g5, 11, %g5 ! Shift into place - brz,pn %g5, vpte_noent ! Valid? - -/* TLB1 ** ICACHE line 4: Quick VPTE miss */ - mov (VALID_SZ_BITS >> 61), %g1 ! upper vpte into %g1 - sllx %g1, 61, %g1 ! finish calc - or %g5, VPTE_BITS, %g5 ! Prepare VPTE data - or %g5, %g1, %g5 ! ... - mov TLB_SFSR, %g1 ! Restore %g1 value - stxa %g5, [%g0] ASI_DTLB_DATA_IN ! Load VPTE into TLB - stxa %g4, [%g1 + %g1] ASI_DMMU ! Restore previous TAG_ACCESS - retry ! Load PTE once again - -#undef VALID_SZ_BITS -#undef VPTE_SHIFT -#undef VPTE_BITS -#undef A -#undef B -#undef C -#undef D -#undef E -#undef F -#undef PMD_SHIFT_LEFT -#undef PMD_SHIFT_RIGHT -#undef PGDIR_SHIFT_LEFT -#undef PGDIR_SHIFT_RIGHT -#undef LOW_MASK_BITS - |
