diff options
Diffstat (limited to 'include/asm-xtensa/mmu_context.h')
| -rw-r--r-- | include/asm-xtensa/mmu_context.h | 269 |
1 files changed, 37 insertions, 232 deletions
diff --git a/include/asm-xtensa/mmu_context.h b/include/asm-xtensa/mmu_context.h index af683a74a4e..f14851f086c 100644 --- a/include/asm-xtensa/mmu_context.h +++ b/include/asm-xtensa/mmu_context.h @@ -16,187 +16,32 @@ #include <linux/stringify.h> #include <asm/pgtable.h> -#include <asm/mmu_context.h> #include <asm/cacheflush.h> #include <asm/tlbflush.h> -/* - * Linux was ported to Xtensa assuming all auto-refill ways in set 0 - * had the same properties (a very likely assumption). Multiple sets - * of auto-refill ways will still work properly, but not as optimally - * as the Xtensa designer may have assumed. - * - * We make this case a hard #error, killing the kernel build, to alert - * the developer to this condition (which is more likely an error). - * You super-duper clever developers can change it to a warning or - * remove it altogether if you think you know what you're doing. :) - */ +#define XCHAL_MMU_ASID_BITS 8 #if (XCHAL_HAVE_TLBS != 1) # error "Linux must have an MMU!" #endif -#if ((XCHAL_ITLB_ARF_WAYS == 0) || (XCHAL_DTLB_ARF_WAYS == 0)) -# error "MMU must have auto-refill ways" -#endif - -#if ((XCHAL_ITLB_ARF_SETS != 1) || (XCHAL_DTLB_ARF_SETS != 1)) -# error Linux may not use all auto-refill ways as efficiently as you think -#endif - -#if (XCHAL_MMU_MAX_PTE_PAGE_SIZE != XCHAL_MMU_MIN_PTE_PAGE_SIZE) -# error Only one page size allowed! -#endif - extern unsigned long asid_cache; -extern pgd_t *current_pgd; - -/* - * Define the number of entries per auto-refill way in set 0 of both I and D - * TLBs. We deal only with set 0 here (an assumption further explained in - * assertions.h). Also, define the total number of ARF entries in both TLBs. - */ - -#define ITLB_ENTRIES_PER_ARF_WAY (XCHAL_ITLB_SET(XCHAL_ITLB_ARF_SET0,ENTRIES)) -#define DTLB_ENTRIES_PER_ARF_WAY (XCHAL_DTLB_SET(XCHAL_DTLB_ARF_SET0,ENTRIES)) - -#define ITLB_ENTRIES \ - (ITLB_ENTRIES_PER_ARF_WAY * (XCHAL_ITLB_SET(XCHAL_ITLB_ARF_SET0,WAYS))) -#define DTLB_ENTRIES \ - (DTLB_ENTRIES_PER_ARF_WAY * (XCHAL_DTLB_SET(XCHAL_DTLB_ARF_SET0,WAYS))) - - -/* - * SMALLEST_NTLB_ENTRIES is the smaller of ITLB_ENTRIES and DTLB_ENTRIES. - * In practice, they are probably equal. This macro simplifies function - * flush_tlb_range(). - */ - -#if (DTLB_ENTRIES < ITLB_ENTRIES) -# define SMALLEST_NTLB_ENTRIES DTLB_ENTRIES -#else -# define SMALLEST_NTLB_ENTRIES ITLB_ENTRIES -#endif - - -/* - * asid_cache tracks only the ASID[USER_RING] field of the RASID special - * register, which is the current user-task asid allocation value. - * mm->context has the same meaning. When it comes time to write the - * asid_cache or mm->context values to the RASID special register, we first - * shift the value left by 8, then insert the value. - * ASID[0] always contains the kernel's asid value, and we reserve three - * other asid values that we never assign to user tasks. - */ - -#define ASID_INC 0x1 -#define ASID_MASK ((1 << XCHAL_MMU_ASID_BITS) - 1) - -/* - * XCHAL_MMU_ASID_INVALID is a configurable Xtensa processor constant - * indicating invalid address space. XCHAL_MMU_ASID_KERNEL is a configurable - * Xtensa processor constant indicating the kernel address space. They can - * be arbitrary values. - * - * We identify three more unique, reserved ASID values to use in the unused - * ring positions. No other user process will be assigned these reserved - * ASID values. - * - * For example, given that - * - * XCHAL_MMU_ASID_INVALID == 0 - * XCHAL_MMU_ASID_KERNEL == 1 - * - * the following maze of #if statements would generate - * - * ASID_RESERVED_1 == 2 - * ASID_RESERVED_2 == 3 - * ASID_RESERVED_3 == 4 - * ASID_FIRST_NONRESERVED == 5 - */ - -#if (XCHAL_MMU_ASID_INVALID != XCHAL_MMU_ASID_KERNEL + 1) -# define ASID_RESERVED_1 ((XCHAL_MMU_ASID_KERNEL + 1) & ASID_MASK) -#else -# define ASID_RESERVED_1 ((XCHAL_MMU_ASID_KERNEL + 2) & ASID_MASK) -#endif - -#if (XCHAL_MMU_ASID_INVALID != ASID_RESERVED_1 + 1) -# define ASID_RESERVED_2 ((ASID_RESERVED_1 + 1) & ASID_MASK) -#else -# define ASID_RESERVED_2 ((ASID_RESERVED_1 + 2) & ASID_MASK) -#endif - -#if (XCHAL_MMU_ASID_INVALID != ASID_RESERVED_2 + 1) -# define ASID_RESERVED_3 ((ASID_RESERVED_2 + 1) & ASID_MASK) -#else -# define ASID_RESERVED_3 ((ASID_RESERVED_2 + 2) & ASID_MASK) -#endif - -#if (XCHAL_MMU_ASID_INVALID != ASID_RESERVED_3 + 1) -# define ASID_FIRST_NONRESERVED ((ASID_RESERVED_3 + 1) & ASID_MASK) -#else -# define ASID_FIRST_NONRESERVED ((ASID_RESERVED_3 + 2) & ASID_MASK) -#endif - -#define ASID_ALL_RESERVED ( ((ASID_RESERVED_1) << 24) + \ - ((ASID_RESERVED_2) << 16) + \ - ((ASID_RESERVED_3) << 8) + \ - ((XCHAL_MMU_ASID_KERNEL)) ) - /* * NO_CONTEXT is the invalid ASID value that we don't ever assign to - * any user or kernel context. NO_CONTEXT is a better mnemonic than - * XCHAL_MMU_ASID_INVALID, so we use it in code instead. - */ - -#define NO_CONTEXT XCHAL_MMU_ASID_INVALID - -#if (KERNEL_RING != 0) -# error The KERNEL_RING really should be zero. -#endif - -#if (USER_RING >= XCHAL_MMU_RINGS) -# error USER_RING cannot be greater than the highest numbered ring. -#endif - -#if (USER_RING == KERNEL_RING) -# error The user and kernel rings really should not be equal. -#endif - -#if (USER_RING == 1) -#define ASID_INSERT(x) ( ((ASID_RESERVED_1) << 24) + \ - ((ASID_RESERVED_2) << 16) + \ - (((x) & (ASID_MASK)) << 8) + \ - ((XCHAL_MMU_ASID_KERNEL)) ) - -#elif (USER_RING == 2) -#define ASID_INSERT(x) ( ((ASID_RESERVED_1) << 24) + \ - (((x) & (ASID_MASK)) << 16) + \ - ((ASID_RESERVED_2) << 8) + \ - ((XCHAL_MMU_ASID_KERNEL)) ) - -#elif (USER_RING == 3) -#define ASID_INSERT(x) ( (((x) & (ASID_MASK)) << 24) + \ - ((ASID_RESERVED_1) << 16) + \ - ((ASID_RESERVED_2) << 8) + \ - ((XCHAL_MMU_ASID_KERNEL)) ) - -#else -#error Goofy value for USER_RING - -#endif /* USER_RING == 1 */ - - -/* - * All unused by hardware upper bits will be considered - * as a software asid extension. + * any user or kernel context. + * + * 0 invalid + * 1 kernel + * 2 reserved + * 3 reserved + * 4...255 available */ -#define ASID_VERSION_MASK ((unsigned long)~(ASID_MASK|(ASID_MASK-1))) -#define ASID_FIRST_VERSION \ - ((unsigned long)(~ASID_VERSION_MASK) + 1 + ASID_FIRST_NONRESERVED) +#define NO_CONTEXT 0 +#define ASID_USER_FIRST 4 +#define ASID_MASK ((1 << XCHAL_MMU_ASID_BITS) - 1) +#define ASID_INSERT(x) (0x03020001 | (((x) & ASID_MASK) << 8)) static inline void set_rasid_register (unsigned long val) { @@ -207,67 +52,28 @@ static inline void set_rasid_register (unsigned long val) static inline unsigned long get_rasid_register (void) { unsigned long tmp; - __asm__ __volatile__ (" rsr %0, "__stringify(RASID)"\n\t" : "=a" (tmp)); + __asm__ __volatile__ (" rsr %0,"__stringify(RASID)"\n\t" : "=a" (tmp)); return tmp; } - -#if ((XCHAL_MMU_ASID_INVALID == 0) && (XCHAL_MMU_ASID_KERNEL == 1)) - static inline void -get_new_mmu_context(struct mm_struct *mm, unsigned long asid) +__get_new_mmu_context(struct mm_struct *mm) { extern void flush_tlb_all(void); - if (! ((asid += ASID_INC) & ASID_MASK) ) { + if (! (++asid_cache & ASID_MASK) ) { flush_tlb_all(); /* start new asid cycle */ - if (!asid) /* fix version if needed */ - asid = ASID_FIRST_VERSION - ASID_FIRST_NONRESERVED; - asid += ASID_FIRST_NONRESERVED; + asid_cache += ASID_USER_FIRST; } - mm->context = asid_cache = asid; -} - -#else -#warning ASID_{INVALID,KERNEL} values impose non-optimal get_new_mmu_context implementation - -/* XCHAL_MMU_ASID_INVALID == 0 and XCHAL_MMU_ASID_KERNEL ==1 are - really the best, but if you insist... */ - -static inline int validate_asid (unsigned long asid) -{ - switch (asid) { - case XCHAL_MMU_ASID_INVALID: - case XCHAL_MMU_ASID_KERNEL: - case ASID_RESERVED_1: - case ASID_RESERVED_2: - case ASID_RESERVED_3: - return 0; /* can't use these values as ASIDs */ - } - return 1; /* valid */ + mm->context = asid_cache; } static inline void -get_new_mmu_context(struct mm_struct *mm, unsigned long asid) +__load_mmu_context(struct mm_struct *mm) { - extern void flush_tlb_all(void); - while (1) { - asid += ASID_INC; - if ( ! (asid & ASID_MASK) ) { - flush_tlb_all(); /* start new asid cycle */ - if (!asid) /* fix version if needed */ - asid = ASID_FIRST_VERSION - ASID_FIRST_NONRESERVED; - asid += ASID_FIRST_NONRESERVED; - break; /* no need to validate here */ - } - if (validate_asid (asid & ASID_MASK)) - break; - } - mm->context = asid_cache = asid; + set_rasid_register(ASID_INSERT(mm->context)); + invalidate_page_directory(); } -#endif - - /* * Initialize the context related info for a new mm_struct * instance. @@ -280,6 +86,20 @@ init_new_context(struct task_struct *tsk, struct mm_struct *mm) return 0; } +/* + * After we have set current->mm to a new value, this activates + * the context for the new mm so we see the new mappings. + */ +static inline void +activate_mm(struct mm_struct *prev, struct mm_struct *next) +{ + /* Unconditionally get a new ASID. */ + + __get_new_mmu_context(next); + __load_mmu_context(next); +} + + static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) { @@ -287,11 +107,10 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, /* Check if our ASID is of an older version and thus invalid */ - if ((next->context ^ asid) & ASID_VERSION_MASK) - get_new_mmu_context(next, asid); + if (next->context == NO_CONTEXT || ((next->context^asid) & ~ASID_MASK)) + __get_new_mmu_context(next); - set_rasid_register (ASID_INSERT(next->context)); - invalidate_page_directory(); + __load_mmu_context(next); } #define deactivate_mm(tsk, mm) do { } while(0) @@ -302,20 +121,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, */ static inline void destroy_context(struct mm_struct *mm) { - /* Nothing to do. */ -} - -/* - * After we have set current->mm to a new value, this activates - * the context for the new mm so we see the new mappings. - */ -static inline void -activate_mm(struct mm_struct *prev, struct mm_struct *next) -{ - /* Unconditionally get a new ASID. */ - - get_new_mmu_context(next, asid_cache); - set_rasid_register (ASID_INSERT(next->context)); invalidate_page_directory(); } |