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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_NOHASH_32_PTE_44x_H
#define _ASM_POWERPC_NOHASH_32_PTE_44x_H
#ifdef __KERNEL__
/*
* Definitions for PPC440
*
* Because of the 3 word TLB entries to support 36-bit addressing,
* the attribute are difficult to map in such a fashion that they
* are easily loaded during exception processing. I decided to
* organize the entry so the ERPN is the only portion in the
* upper word of the PTE and the attribute bits below are packed
* in as sensibly as they can be in the area below a 4KB page size
* oriented RPN. This at least makes it easy to load the RPN and
* ERPN fields in the TLB. -Matt
*
* This isn't entirely true anymore, at least some bits are now
* easier to move into the TLB from the PTE. -BenH.
*
* Note that these bits preclude future use of a page size
* less than 4KB.
*
*
* PPC 440 core has following TLB attribute fields;
*
* TLB1:
* 0 1 2 3 4 ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
* RPN................................. - - - - - - ERPN.......
*
* TLB2:
* 0 1 2 3 4 ... 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
* - - - - - - U0 U1 U2 U3 W I M G E - UX UW UR SX SW SR
*
* Newer 440 cores (440x6 as used on AMCC 460EX/460GT) have additional
* TLB2 storage attribute fields. Those are:
*
* TLB2:
* 0...10 11 12 13 14 15 16...31
* no change WL1 IL1I IL1D IL2I IL2D no change
*
* There are some constrains and options, to decide mapping software bits
* into TLB entry.
*
* - PRESENT *must* be in the bottom three bits because swap cache
* entries use the top 29 bits for TLB2.
*
* - CACHE COHERENT bit (M) has no effect on original PPC440 cores,
* because it doesn't support SMP. However, some later 460 variants
* have -some- form of SMP support and so I keep the bit there for
* future use
*
* With the PPC 44x Linux implementation, the 0-11th LSBs of the PTE are used
* for memory protection related functions (see PTE structure in
* include/asm-ppc/mmu.h). The _PAGE_XXX definitions in this file map to the
* above bits. Note that the bit values are CPU specific, not architecture
* specific.
*
* The kernel PTE entry holds an arch-dependent swp_entry structure under
* certain situations. In other words, in such situations some portion of
* the PTE bits are used as a swp_entry. In the PPC implementation, the
* 3-24th LSB are shared with swp_entry, however the 0-2nd three LSB still
* hold protection values. That means the three protection bits are
* reserved for both PTE and SWAP entry at the most significant three
* LSBs.
*
* There are three protection bits available for SWAP entry:
* _PAGE_PRESENT
* _PAGE_HASHPTE (if HW has)
*
* So those three bits have to be inside of 0-2nd LSB of PTE.
*
*/
#define _PAGE_PRESENT 0x00000001 /* S: PTE valid */
#define _PAGE_RW 0x00000002 /* S: Write permission */
#define _PAGE_EXEC 0x00000004 /* H: Execute permission */
#define _PAGE_ACCESSED 0x00000008 /* S: Page referenced */
#define _PAGE_DIRTY 0x00000010 /* S: Page dirty */
#define _PAGE_SPECIAL 0x00000020 /* S: Special page */
#define _PAGE_USER 0x00000040 /* S: User page */
#define _PAGE_ENDIAN 0x00000080 /* H: E bit */
#define _PAGE_GUARDED 0x00000100 /* H: G bit */
#define _PAGE_COHERENT 0x00000200 /* H: M bit */
#define _PAGE_NO_CACHE 0x00000400 /* H: I bit */
#define _PAGE_WRITETHRU 0x00000800 /* H: W bit */
/* TODO: Add large page lowmem mapping support */
#define _PMD_PRESENT 0
#define _PMD_PRESENT_MASK (PAGE_MASK)
#define _PMD_BAD (~PAGE_MASK)
/* ERPN in a PTE never gets cleared, ignore it */
#define _PTE_NONE_MASK 0xffffffff00000000ULL
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_NOHASH_32_PTE_44x_H */
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