1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_POWERPC_NOHASH_32_PTE_44x_H 3 #define _ASM_POWERPC_NOHASH_32_PTE_44x_H 4 #ifdef __KERNEL__ 5 6 /* 7 * Definitions for PPC440 8 * 9 * Because of the 3 word TLB entries to support 36-bit addressing, 10 * the attribute are difficult to map in such a fashion that they 11 * are easily loaded during exception processing. I decided to 12 * organize the entry so the ERPN is the only portion in the 13 * upper word of the PTE and the attribute bits below are packed 14 * in as sensibly as they can be in the area below a 4KB page size 15 * oriented RPN. This at least makes it easy to load the RPN and 16 * ERPN fields in the TLB. -Matt 17 * 18 * This isn't entirely true anymore, at least some bits are now 19 * easier to move into the TLB from the PTE. -BenH. 20 * 21 * Note that these bits preclude future use of a page size 22 * less than 4KB. 23 * 24 * 25 * PPC 440 core has following TLB attribute fields; 26 * 27 * TLB1: 28 * 0 1 2 3 4 ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 29 * RPN................................. - - - - - - ERPN....... 30 * 31 * TLB2: 32 * 0 1 2 3 4 ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 33 * - - - - - - U0 U1 U2 U3 W I M G E - UX UW UR SX SW SR 34 * 35 * Newer 440 cores (440x6 as used on AMCC 460EX/460GT) have additional 36 * TLB2 storage attribute fields. Those are: 37 * 38 * TLB2: 39 * 0...10 11 12 13 14 15 16...31 40 * no change WL1 IL1I IL1D IL2I IL2D no change 41 * 42 * There are some constrains and options, to decide mapping software bits 43 * into TLB entry. 44 * 45 * - PRESENT *must* be in the bottom three bits because swap cache 46 * entries use the top 29 bits for TLB2. 47 * 48 * - CACHE COHERENT bit (M) has no effect on original PPC440 cores, 49 * because it doesn't support SMP. However, some later 460 variants 50 * have -some- form of SMP support and so I keep the bit there for 51 * future use 52 * 53 * With the PPC 44x Linux implementation, the 0-11th LSBs of the PTE are used 54 * for memory protection related functions (see PTE structure in 55 * include/asm-ppc/mmu.h). The _PAGE_XXX definitions in this file map to the 56 * above bits. Note that the bit values are CPU specific, not architecture 57 * specific. 58 * 59 * The kernel PTE entry can be an ordinary PTE mapping a page or a special swap 60 * PTE. In case of a swap PTE, LSB 2-24 are used to store information regarding 61 * the swap entry. However LSB 0-1 still hold protection values, for example, 62 * to distinguish swap PTEs from ordinary PTEs, and must be used with care. 63 */ 64 65 #define _PAGE_PRESENT 0x00000001 /* S: PTE valid */ 66 #define _PAGE_WRITE 0x00000002 /* S: Write permission */ 67 #define _PAGE_EXEC 0x00000004 /* H: Execute permission */ 68 #define _PAGE_READ 0x00000008 /* S: Read permission */ 69 #define _PAGE_DIRTY 0x00000010 /* S: Page dirty */ 70 #define _PAGE_SPECIAL 0x00000020 /* S: Special page */ 71 #define _PAGE_ACCESSED 0x00000040 /* S: Page referenced */ 72 #define _PAGE_ENDIAN 0x00000080 /* H: E bit */ 73 #define _PAGE_GUARDED 0x00000100 /* H: G bit */ 74 #define _PAGE_COHERENT 0x00000200 /* H: M bit */ 75 #define _PAGE_NO_CACHE 0x00000400 /* H: I bit */ 76 #define _PAGE_WRITETHRU 0x00000800 /* H: W bit */ 77 78 /* No page size encoding in the linux PTE */ 79 #define _PAGE_PSIZE 0 80 81 /* TODO: Add large page lowmem mapping support */ 82 #define _PMD_PRESENT 0 83 #define _PMD_PRESENT_MASK (PAGE_MASK) 84 #define _PMD_BAD (~PAGE_MASK) 85 #define _PMD_USER 0 86 87 /* ERPN in a PTE never gets cleared, ignore it */ 88 #define _PTE_NONE_MASK 0xffffffff00000000ULL 89 90 /* 91 * We define 2 sets of base prot bits, one for basic pages (ie, 92 * cacheable kernel and user pages) and one for non cacheable 93 * pages. We always set _PAGE_COHERENT when SMP is enabled or 94 * the processor might need it for DMA coherency. 95 */ 96 #define _PAGE_BASE_NC (_PAGE_PRESENT | _PAGE_ACCESSED) 97 #if defined(CONFIG_SMP) 98 #define _PAGE_BASE (_PAGE_BASE_NC | _PAGE_COHERENT) 99 #else 100 #define _PAGE_BASE (_PAGE_BASE_NC) 101 #endif 102 103 #include <asm/pgtable-masks.h> 104 105 #endif /* __KERNEL__ */ 106 #endif /* _ASM_POWERPC_NOHASH_32_PTE_44x_H */ 107