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Diffstat (limited to 'arch/powerpc/include/asm/nohash/32/pte-44x.h')
| -rw-r--r-- | arch/powerpc/include/asm/nohash/32/pte-44x.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/nohash/32/pte-44x.h b/arch/powerpc/include/asm/nohash/32/pte-44x.h new file mode 100644 index 000000000..b7ed13cee --- /dev/null +++ b/arch/powerpc/include/asm/nohash/32/pte-44x.h @@ -0,0 +1,118 @@ +/* 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 can be an ordinary PTE mapping a page or a special swap + * PTE. In case of a swap PTE, LSB 2-24 are used to store information regarding + * the swap entry. However LSB 0-1 still hold protection values, for example, + * to distinguish swap PTEs from ordinary PTEs, and must be used with care. + */ + +#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 */ + +/* No page size encoding in the linux PTE */ +#define _PAGE_PSIZE 0 + +#define _PAGE_KERNEL_RO 0 +#define _PAGE_KERNEL_ROX _PAGE_EXEC +#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW) +#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC) + +/* TODO: Add large page lowmem mapping support */ +#define _PMD_PRESENT 0 +#define _PMD_PRESENT_MASK (PAGE_MASK) +#define _PMD_BAD (~PAGE_MASK) +#define _PMD_USER 0 + +/* ERPN in a PTE never gets cleared, ignore it */ +#define _PTE_NONE_MASK 0xffffffff00000000ULL + +/* + * We define 2 sets of base prot bits, one for basic pages (ie, + * cacheable kernel and user pages) and one for non cacheable + * pages. We always set _PAGE_COHERENT when SMP is enabled or + * the processor might need it for DMA coherency. + */ +#define _PAGE_BASE_NC (_PAGE_PRESENT | _PAGE_ACCESSED) +#if defined(CONFIG_SMP) +#define _PAGE_BASE (_PAGE_BASE_NC | _PAGE_COHERENT) +#else +#define _PAGE_BASE (_PAGE_BASE_NC) +#endif + +/* Permission masks used to generate the __P and __S table */ +#define PAGE_NONE __pgprot(_PAGE_BASE) +#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) +#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC) +#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) +#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) +#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER) +#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) + +#endif /* __KERNEL__ */ +#endif /* _ASM_POWERPC_NOHASH_32_PTE_44x_H */ |