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authorNicolas Pitre <nicolas.pitre@linaro.org>2010-12-15 15:14:45 -0500
committerNicolas Pitre <nico@fluxnic.net>2010-12-19 12:56:46 -0500
commit39af22a79232373764904576f31572f1db76af10 (patch)
tree20d31ab6a01b93dabe9c05277bcb1413e978648b
parentb0c3844d8af6b9f3f18f31e1b0502fbefa2166be (diff)
ARM: get rid of kmap_high_l1_vipt()
Since commit 3e4d3af501 "mm: stack based kmap_atomic()", it is no longer necessary to carry an ad hoc version of kmap_atomic() added in commit 7e5a69e83b "ARM: 6007/1: fix highmem with VIPT cache and DMA" to cope with reentrancy. In fact, it is now actively wrong to rely on fixed kmap type indices (namely KM_L1_CACHE) as kmap_atomic() totally ignores them now and a concurrent instance of it may reuse any slot for any purpose. Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
-rw-r--r--arch/arm/include/asm/highmem.h3
-rw-r--r--arch/arm/mm/dma-mapping.c7
-rw-r--r--arch/arm/mm/flush.c7
-rw-r--r--arch/arm/mm/highmem.c87
4 files changed, 8 insertions, 96 deletions
diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h
index 1fc684e70ab6..7080e2c8fa62 100644
--- a/arch/arm/include/asm/highmem.h
+++ b/arch/arm/include/asm/highmem.h
@@ -25,9 +25,6 @@ extern void *kmap_high(struct page *page);
extern void *kmap_high_get(struct page *page);
extern void kunmap_high(struct page *page);
-extern void *kmap_high_l1_vipt(struct page *page, pte_t *saved_pte);
-extern void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte);
-
/*
* The following functions are already defined by <linux/highmem.h>
* when CONFIG_HIGHMEM is not set.
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index ac6a36142fcd..809f1bf9fa29 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -17,6 +17,7 @@
#include <linux/init.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
+#include <linux/highmem.h>
#include <asm/memory.h>
#include <asm/highmem.h>
@@ -480,10 +481,10 @@ static void dma_cache_maint_page(struct page *page, unsigned long offset,
op(vaddr, len, dir);
kunmap_high(page);
} else if (cache_is_vipt()) {
- pte_t saved_pte;
- vaddr = kmap_high_l1_vipt(page, &saved_pte);
+ /* unmapped pages might still be cached */
+ vaddr = kmap_atomic(page);
op(vaddr + offset, len, dir);
- kunmap_high_l1_vipt(page, saved_pte);
+ kunmap_atomic(vaddr);
}
} else {
vaddr = page_address(page) + offset;
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 391ffae75098..c29f2839f1d2 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
+#include <linux/highmem.h>
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
@@ -180,10 +181,10 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page)
__cpuc_flush_dcache_area(addr, PAGE_SIZE);
kunmap_high(page);
} else if (cache_is_vipt()) {
- pte_t saved_pte;
- addr = kmap_high_l1_vipt(page, &saved_pte);
+ /* unmapped pages might still be cached */
+ addr = kmap_atomic(page);
__cpuc_flush_dcache_area(addr, PAGE_SIZE);
- kunmap_high_l1_vipt(page, saved_pte);
+ kunmap_atomic(addr);
}
}
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)
pte = TOP_PTE(vaddr);
return pte_page(*pte);
}
-
-#ifdef CONFIG_CPU_CACHE_VIPT
-
-#include <linux/percpu.h>
-
-/*
- * The VIVT cache of a highmem page is always flushed before the page
- * is unmapped. Hence unmapped highmem pages need no cache maintenance
- * in that case.
- *
- * However unmapped pages may still be cached with a VIPT cache, and
- * it is not possible to perform cache maintenance on them using physical
- * addresses unfortunately. So we have no choice but to set up a temporary
- * virtual mapping for that purpose.
- *
- * Yet this VIPT cache maintenance may be triggered from DMA support
- * functions which are possibly called from interrupt context. As we don't
- * want to keep interrupt disabled all the time when such maintenance is
- * taking place, we therefore allow for some reentrancy by preserving and
- * restoring the previous fixmap entry before the interrupted context is
- * resumed. If the reentrancy depth is 0 then there is no need to restore
- * the previous fixmap, and leaving the current one in place allow it to
- * be reused the next time without a TLB flush (common with DMA).
- */
-
-static DEFINE_PER_CPU(int, kmap_high_l1_vipt_depth);
-
-void *kmap_high_l1_vipt(struct page *page, pte_t *saved_pte)
-{
- unsigned int idx, cpu;
- int *depth;
- unsigned long vaddr, flags;
- pte_t pte, *ptep;
-
- if (!in_interrupt())
- preempt_disable();
-
- cpu = smp_processor_id();
- depth = &per_cpu(kmap_high_l1_vipt_depth, cpu);
-
- idx = KM_L1_CACHE + KM_TYPE_NR * cpu;
- vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
- ptep = TOP_PTE(vaddr);
- pte = mk_pte(page, kmap_prot);
-
- raw_local_irq_save(flags);
- (*depth)++;
- if (pte_val(*ptep) == pte_val(pte)) {
- *saved_pte = pte;
- } else {
- *saved_pte = *ptep;
- set_pte_ext(ptep, pte, 0);
- local_flush_tlb_kernel_page(vaddr);
- }
- raw_local_irq_restore(flags);
-
- return (void *)vaddr;
-}
-
-void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte)
-{
- unsigned int idx, cpu = smp_processor_id();
- int *depth = &per_cpu(kmap_high_l1_vipt_depth, cpu);
- unsigned long vaddr, flags;
- pte_t pte, *ptep;
-
- idx = KM_L1_CACHE + KM_TYPE_NR * cpu;
- vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
- ptep = TOP_PTE(vaddr);
- pte = mk_pte(page, kmap_prot);
-
- BUG_ON(pte_val(*ptep) != pte_val(pte));
- BUG_ON(*depth <= 0);
-
- raw_local_irq_save(flags);
- (*depth)--;
- if (*depth != 0 && pte_val(pte) != pte_val(saved_pte)) {
- set_pte_ext(ptep, saved_pte, 0);
- local_flush_tlb_kernel_page(vaddr);
- }
- raw_local_irq_restore(flags);
-
- if (!in_interrupt())
- preempt_enable();
-}
-
-#endif /* CONFIG_CPU_CACHE_VIPT */