| #ifndef _ASM_POWERPC_PTE_8xx_H |
| #define _ASM_POWERPC_PTE_8xx_H |
| #ifdef __KERNEL__ |
| |
| /* |
| * The PowerPC MPC8xx uses a TLB with hardware assisted, software tablewalk. |
| * We also use the two level tables, but we can put the real bits in them |
| * needed for the TLB and tablewalk. These definitions require Mx_CTR.PPM = 0, |
| * Mx_CTR.PPCS = 0, and MD_CTR.TWAM = 1. The level 2 descriptor has |
| * additional page protection (when Mx_CTR.PPCS = 1) that allows TLB hit |
| * based upon user/super access. The TLB does not have accessed nor write |
| * protect. We assume that if the TLB get loaded with an entry it is |
| * accessed, and overload the changed bit for write protect. We use |
| * two bits in the software pte that are supposed to be set to zero in |
| * the TLB entry (24 and 25) for these indicators. Although the level 1 |
| * descriptor contains the guarded and writethrough/copyback bits, we can |
| * set these at the page level since they get copied from the Mx_TWC |
| * register when the TLB entry is loaded. We will use bit 27 for guard, since |
| * that is where it exists in the MD_TWC, and bit 26 for writethrough. |
| * These will get masked from the level 2 descriptor at TLB load time, and |
| * copied to the MD_TWC before it gets loaded. |
| * Large page sizes added. We currently support two sizes, 4K and 8M. |
| * This also allows a TLB hander optimization because we can directly |
| * load the PMD into MD_TWC. The 8M pages are only used for kernel |
| * mapping of well known areas. The PMD (PGD) entries contain control |
| * flags in addition to the address, so care must be taken that the |
| * software no longer assumes these are only pointers. |
| */ |
| |
| /* Definitions for 8xx embedded chips. */ |
| #define _PAGE_PRESENT 0x0001 /* Page is valid */ |
| #define _PAGE_FILE 0x0002 /* when !present: nonlinear file mapping */ |
| #define _PAGE_NO_CACHE 0x0002 /* I: cache inhibit */ |
| #define _PAGE_SHARED 0x0004 /* No ASID (context) compare */ |
| #define _PAGE_SPECIAL 0x0008 /* SW entry, forced to 0 by the TLB miss */ |
| #define _PAGE_DIRTY 0x0100 /* C: page changed */ |
| |
| /* These 4 software bits must be masked out when the entry is loaded |
| * into the TLB, 1 SW bit left(0x0080). |
| */ |
| #define _PAGE_GUARDED 0x0010 /* software: guarded access */ |
| #define _PAGE_ACCESSED 0x0020 /* software: page referenced */ |
| #define _PAGE_WRITETHRU 0x0040 /* software: caching is write through */ |
| |
| /* Setting any bits in the nibble with the follow two controls will |
| * require a TLB exception handler change. It is assumed unused bits |
| * are always zero. |
| */ |
| #define _PAGE_RW 0x0400 /* lsb PP bits, inverted in HW */ |
| #define _PAGE_USER 0x0800 /* msb PP bits */ |
| |
| #define _PMD_PRESENT 0x0001 |
| #define _PMD_BAD 0x0ff0 |
| #define _PMD_PAGE_MASK 0x000c |
| #define _PMD_PAGE_8M 0x000c |
| |
| #define _PTE_NONE_MASK _PAGE_ACCESSED |
| |
| /* Until my rework is finished, 8xx still needs atomic PTE updates */ |
| #define PTE_ATOMIC_UPDATES 1 |
| |
| /* We need to add _PAGE_SHARED to kernel pages */ |
| #define _PAGE_KERNEL_RO (_PAGE_SHARED) |
| #define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE) |
| |
| #endif /* __KERNEL__ */ |
| #endif /* _ASM_POWERPC_PTE_8xx_H */ |
