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-rw-r--r--arch/arm/mm/highmem.c87
1 files changed, 0 insertions, 87 deletions
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
index c435fd9e1da9..807c0573abbe 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -140,90 +140,3 @@ struct page *kmap_atomic_to_page(const void *ptr)
140 pte = TOP_PTE(vaddr); 140 pte = TOP_PTE(vaddr);
141 return pte_page(*pte); 141 return pte_page(*pte);
142} 142}
143
144#ifdef CONFIG_CPU_CACHE_VIPT
145
146#include <linux/percpu.h>
147
148/*
149 * The VIVT cache of a highmem page is always flushed before the page
150 * is unmapped. Hence unmapped highmem pages need no cache maintenance
151 * in that case.
152 *
153 * However unmapped pages may still be cached with a VIPT cache, and
154 * it is not possible to perform cache maintenance on them using physical
155 * addresses unfortunately. So we have no choice but to set up a temporary
156 * virtual mapping for that purpose.
157 *
158 * Yet this VIPT cache maintenance may be triggered from DMA support
159 * functions which are possibly called from interrupt context. As we don't
160 * want to keep interrupt disabled all the time when such maintenance is
161 * taking place, we therefore allow for some reentrancy by preserving and
162 * restoring the previous fixmap entry before the interrupted context is
163 * resumed. If the reentrancy depth is 0 then there is no need to restore
164 * the previous fixmap, and leaving the current one in place allow it to
165 * be reused the next time without a TLB flush (common with DMA).
166 */
167
168static DEFINE_PER_CPU(int, kmap_high_l1_vipt_depth);
169
170void *kmap_high_l1_vipt(struct page *page, pte_t *saved_pte)
171{
172 unsigned int idx, cpu;
173 int *depth;
174 unsigned long vaddr, flags;
175 pte_t pte, *ptep;
176
177 if (!in_interrupt())
178 preempt_disable();
179
180 cpu = smp_processor_id();
181 depth = &per_cpu(kmap_high_l1_vipt_depth, cpu);
182
183 idx = KM_L1_CACHE + KM_TYPE_NR * cpu;
184 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
185 ptep = TOP_PTE(vaddr);
186 pte = mk_pte(page, kmap_prot);
187
188 raw_local_irq_save(flags);
189 (*depth)++;
190 if (pte_val(*ptep) == pte_val(pte)) {
191 *saved_pte = pte;
192 } else {
193 *saved_pte = *ptep;
194 set_pte_ext(ptep, pte, 0);
195 local_flush_tlb_kernel_page(vaddr);
196 }
197 raw_local_irq_restore(flags);
198
199 return (void *)vaddr;
200}
201
202void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte)
203{
204 unsigned int idx, cpu = smp_processor_id();
205 int *depth = &per_cpu(kmap_high_l1_vipt_depth, cpu);
206 unsigned long vaddr, flags;
207 pte_t pte, *ptep;
208
209 idx = KM_L1_CACHE + KM_TYPE_NR * cpu;
210 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
211 ptep = TOP_PTE(vaddr);
212 pte = mk_pte(page, kmap_prot);
213
214 BUG_ON(pte_val(*ptep) != pte_val(pte));
215 BUG_ON(*depth <= 0);
216
217 raw_local_irq_save(flags);
218 (*depth)--;
219 if (*depth != 0 && pte_val(pte) != pte_val(saved_pte)) {
220 set_pte_ext(ptep, saved_pte, 0);
221 local_flush_tlb_kernel_page(vaddr);
222 }
223 raw_local_irq_restore(flags);
224
225 if (!in_interrupt())
226 preempt_enable();
227}
228
229#endif /* CONFIG_CPU_CACHE_VIPT */