1 #ifndef _ASM_IA64_TLB_H
2 #define _ASM_IA64_TLB_H
4 * Based on <asm-generic/tlb.h>.
6 * Copyright (C) 2002-2003 Hewlett-Packard Co
7 * David Mosberger-Tang <davidm@hpl.hp.com>
10 * Removing a translation from a page table (including TLB-shootdown) is a four-step
13 * (1) Flush (virtual) caches --- ensures virtual memory is coherent with kernel memory
14 * (this is a no-op on ia64).
15 * (2) Clear the relevant portions of the page-table
16 * (3) Flush the TLBs --- ensures that stale content is gone from CPU TLBs
17 * (4) Release the pages that were freed up in step (2).
19 * Note that the ordering of these steps is crucial to avoid races on MP machines.
21 * The Linux kernel defines several platform-specific hooks for TLB-shootdown. When
22 * unmapping a portion of the virtual address space, these hooks are called according to
23 * the following template:
25 * tlb <- tlb_gather_mmu(mm, full_mm_flush); // start unmap for address space MM
27 * for each vma that needs a shootdown do {
28 * tlb_start_vma(tlb, vma);
29 * for each page-table-entry PTE that needs to be removed do {
30 * tlb_remove_tlb_entry(tlb, pte, address);
31 * if (pte refers to a normal page) {
32 * tlb_remove_page(tlb, page);
35 * tlb_end_vma(tlb, vma);
38 * tlb_finish_mmu(tlb, start, end); // finish unmap for address space MM
41 #include <linux/pagemap.h>
42 #include <linux/swap.h>
44 #include <asm/pgalloc.h>
45 #include <asm/processor.h>
46 #include <asm/tlbflush.h>
47 #include <asm/machvec.h>
50 # define FREE_PTE_NR 2048
51 # define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
53 # define FREE_PTE_NR 0
54 # define tlb_fast_mode(tlb) (1)
59 unsigned int nr
; /* == ~0U => fast mode */
60 unsigned char fullmm
; /* non-zero means full mm flush */
61 unsigned char need_flush
; /* really unmapped some PTEs? */
62 unsigned long start_addr
;
63 unsigned long end_addr
;
64 struct page
*pages
[FREE_PTE_NR
];
67 struct ia64_tr_entry
{
72 }; /*Record for tr entry!*/
74 extern int ia64_itr_entry(u64 target_mask
, u64 va
, u64 pte
, u64 log_size
);
75 extern void ia64_ptr_entry(u64 target_mask
, int slot
);
77 extern struct ia64_tr_entry
*ia64_idtrs
[NR_CPUS
];
80 region register macros
82 #define RR_TO_VE(val) (((val) >> 0) & 0x0000000000000001)
83 #define RR_VE(val) (((val) & 0x0000000000000001) << 0)
84 #define RR_VE_MASK 0x0000000000000001L
86 #define RR_TO_PS(val) (((val) >> 2) & 0x000000000000003f)
87 #define RR_PS(val) (((val) & 0x000000000000003f) << 2)
88 #define RR_PS_MASK 0x00000000000000fcL
90 #define RR_RID_MASK 0x00000000ffffff00L
91 #define RR_TO_RID(val) ((val >> 8) & 0xffffff)
93 /* Users of the generic TLB shootdown code must declare this storage space. */
94 DECLARE_PER_CPU(struct mmu_gather
, mmu_gathers
);
97 * Flush the TLB for address range START to END and, if not in fast mode, release the
98 * freed pages that where gathered up to this point.
101 ia64_tlb_flush_mmu (struct mmu_gather
*tlb
, unsigned long start
, unsigned long end
)
105 if (!tlb
->need_flush
)
111 * Tearing down the entire address space. This happens both as a result
112 * of exit() and execve(). The latter case necessitates the call to
113 * flush_tlb_mm() here.
115 flush_tlb_mm(tlb
->mm
);
116 } else if (unlikely (end
- start
>= 1024*1024*1024*1024UL
117 || REGION_NUMBER(start
) != REGION_NUMBER(end
- 1)))
120 * If we flush more than a tera-byte or across regions, we're probably
121 * better off just flushing the entire TLB(s). This should be very rare
122 * and is not worth optimizing for.
127 * XXX fix me: flush_tlb_range() should take an mm pointer instead of a
130 struct vm_area_struct vma
;
133 /* flush the address range from the tlb: */
134 flush_tlb_range(&vma
, start
, end
);
135 /* now flush the virt. page-table area mapping the address range: */
136 flush_tlb_range(&vma
, ia64_thash(start
), ia64_thash(end
));
139 /* lastly, release the freed pages */
141 if (!tlb_fast_mode(tlb
)) {
144 tlb
->start_addr
= ~0UL;
145 for (i
= 0; i
< nr
; ++i
)
146 free_page_and_swap_cache(tlb
->pages
[i
]);
151 * Return a pointer to an initialized struct mmu_gather.
153 static inline struct mmu_gather
*
154 tlb_gather_mmu (struct mm_struct
*mm
, unsigned int full_mm_flush
)
156 struct mmu_gather
*tlb
= &get_cpu_var(mmu_gathers
);
160 * Use fast mode if only 1 CPU is online.
162 * It would be tempting to turn on fast-mode for full_mm_flush as well. But this
163 * doesn't work because of speculative accesses and software prefetching: the page
164 * table of "mm" may (and usually is) the currently active page table and even
165 * though the kernel won't do any user-space accesses during the TLB shoot down, a
166 * compiler might use speculation or lfetch.fault on what happens to be a valid
167 * user-space address. This in turn could trigger a TLB miss fault (or a VHPT
168 * walk) and re-insert a TLB entry we just removed. Slow mode avoids such
169 * problems. (We could make fast-mode work by switching the current task to a
170 * different "mm" during the shootdown.) --davidm 08/02/2002
172 tlb
->nr
= (num_online_cpus() == 1) ? ~0U : 0;
173 tlb
->fullmm
= full_mm_flush
;
174 tlb
->start_addr
= ~0UL;
179 * Called at the end of the shootdown operation to free up any resources that were
183 tlb_finish_mmu (struct mmu_gather
*tlb
, unsigned long start
, unsigned long end
)
186 * Note: tlb->nr may be 0 at this point, so we can't rely on tlb->start_addr and
189 ia64_tlb_flush_mmu(tlb
, start
, end
);
191 /* keep the page table cache within bounds */
194 put_cpu_var(mmu_gathers
);
198 * Logically, this routine frees PAGE. On MP machines, the actual freeing of the page
199 * must be delayed until after the TLB has been flushed (see comments at the beginning of
203 tlb_remove_page (struct mmu_gather
*tlb
, struct page
*page
)
207 if (tlb_fast_mode(tlb
)) {
208 free_page_and_swap_cache(page
);
211 tlb
->pages
[tlb
->nr
++] = page
;
212 if (tlb
->nr
>= FREE_PTE_NR
)
213 ia64_tlb_flush_mmu(tlb
, tlb
->start_addr
, tlb
->end_addr
);
217 * Remove TLB entry for PTE mapped at virtual address ADDRESS. This is called for any
218 * PTE, not just those pointing to (normal) physical memory.
221 __tlb_remove_tlb_entry (struct mmu_gather
*tlb
, pte_t
*ptep
, unsigned long address
)
223 if (tlb
->start_addr
== ~0UL)
224 tlb
->start_addr
= address
;
225 tlb
->end_addr
= address
+ PAGE_SIZE
;
228 #define tlb_migrate_finish(mm) platform_tlb_migrate_finish(mm)
230 #define tlb_start_vma(tlb, vma) do { } while (0)
231 #define tlb_end_vma(tlb, vma) do { } while (0)
233 #define tlb_remove_tlb_entry(tlb, ptep, addr) \
235 tlb->need_flush = 1; \
236 __tlb_remove_tlb_entry(tlb, ptep, addr); \
239 #define pte_free_tlb(tlb, ptep, address) \
241 tlb->need_flush = 1; \
242 __pte_free_tlb(tlb, ptep, address); \
245 #define pmd_free_tlb(tlb, ptep, address) \
247 tlb->need_flush = 1; \
248 __pmd_free_tlb(tlb, ptep, address); \
251 #define pud_free_tlb(tlb, pudp, address) \
253 tlb->need_flush = 1; \
254 __pud_free_tlb(tlb, pudp, address); \
257 #endif /* _ASM_IA64_TLB_H */