1 #ifndef _ASM_POWERPC_NOHASH_32_PTE_44x_H 2 #define _ASM_POWERPC_NOHASH_32_PTE_44x_H 3 #ifdef __KERNEL__ 4 5 /* 6 * Definitions for PPC440 7 * 8 * Because of the 3 word TLB entries to support 36-bit addressing, 9 * the attribute are difficult to map in such a fashion that they 10 * are easily loaded during exception processing. I decided to 11 * organize the entry so the ERPN is the only portion in the 12 * upper word of the PTE and the attribute bits below are packed 13 * in as sensibly as they can be in the area below a 4KB page size 14 * oriented RPN. This at least makes it easy to load the RPN and 15 * ERPN fields in the TLB. -Matt 16 * 17 * This isn't entirely true anymore, at least some bits are now 18 * easier to move into the TLB from the PTE. -BenH. 19 * 20 * Note that these bits preclude future use of a page size 21 * less than 4KB. 22 * 23 * 24 * PPC 440 core has following TLB attribute fields; 25 * 26 * TLB1: 27 * 0 1 2 3 4 ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 28 * RPN................................. - - - - - - ERPN....... 29 * 30 * TLB2: 31 * 0 1 2 3 4 ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 * - - - - - - U0 U1 U2 U3 W I M G E - UX UW UR SX SW SR 33 * 34 * Newer 440 cores (440x6 as used on AMCC 460EX/460GT) have additional 35 * TLB2 storage attribute fields. Those are: 36 * 37 * TLB2: 38 * 0...10 11 12 13 14 15 16...31 39 * no change WL1 IL1I IL1D IL2I IL2D no change 40 * 41 * There are some constrains and options, to decide mapping software bits 42 * into TLB entry. 43 * 44 * - PRESENT *must* be in the bottom three bits because swap cache 45 * entries use the top 29 bits for TLB2. 46 * 47 * - CACHE COHERENT bit (M) has no effect on original PPC440 cores, 48 * because it doesn't support SMP. However, some later 460 variants 49 * have -some- form of SMP support and so I keep the bit there for 50 * future use 51 * 52 * With the PPC 44x Linux implementation, the 0-11th LSBs of the PTE are used 53 * for memory protection related functions (see PTE structure in 54 * include/asm-ppc/mmu.h). The _PAGE_XXX definitions in this file map to the 55 * above bits. Note that the bit values are CPU specific, not architecture 56 * specific. 57 * 58 * The kernel PTE entry holds an arch-dependent swp_entry structure under 59 * certain situations. In other words, in such situations some portion of 60 * the PTE bits are used as a swp_entry. In the PPC implementation, the 61 * 3-24th LSB are shared with swp_entry, however the 0-2nd three LSB still 62 * hold protection values. That means the three protection bits are 63 * reserved for both PTE and SWAP entry at the most significant three 64 * LSBs. 65 * 66 * There are three protection bits available for SWAP entry: 67 * _PAGE_PRESENT 68 * _PAGE_HASHPTE (if HW has) 69 * 70 * So those three bits have to be inside of 0-2nd LSB of PTE. 71 * 72 */ 73 74 #define _PAGE_PRESENT 0x00000001 /* S: PTE valid */ 75 #define _PAGE_RW 0x00000002 /* S: Write permission */ 76 #define _PAGE_EXEC 0x00000004 /* H: Execute permission */ 77 #define _PAGE_ACCESSED 0x00000008 /* S: Page referenced */ 78 #define _PAGE_DIRTY 0x00000010 /* S: Page dirty */ 79 #define _PAGE_SPECIAL 0x00000020 /* S: Special page */ 80 #define _PAGE_USER 0x00000040 /* S: User page */ 81 #define _PAGE_ENDIAN 0x00000080 /* H: E bit */ 82 #define _PAGE_GUARDED 0x00000100 /* H: G bit */ 83 #define _PAGE_COHERENT 0x00000200 /* H: M bit */ 84 #define _PAGE_NO_CACHE 0x00000400 /* H: I bit */ 85 #define _PAGE_WRITETHRU 0x00000800 /* H: W bit */ 86 87 /* TODO: Add large page lowmem mapping support */ 88 #define _PMD_PRESENT 0 89 #define _PMD_PRESENT_MASK (PAGE_MASK) 90 #define _PMD_BAD (~PAGE_MASK) 91 92 /* ERPN in a PTE never gets cleared, ignore it */ 93 #define _PTE_NONE_MASK 0xffffffff00000000ULL 94 95 96 #endif /* __KERNEL__ */ 97 #endif /* _ASM_POWERPC_NOHASH_32_PTE_44x_H */ 98