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Subject[PATCH v3 2/2] ARM : change fixmap mapping region to support 32 CPUs
Date
In 32-bit ARM systems, the fixmap mapping region can support
no more than 14 CPUs(total: 896k; one CPU: 64K). And we can
configure NR_CPUS up to 32. So there is a mismatch.

This patch moves fixmapping region downwards to region
0xffc00000-0xffe00000. Then the fixmap mapping region can
support up to 32 CPUs

Signed-off-by: Liu Hua <sdu.liu@huawei.com>
---
Documentation/arm/memory.txt | 2 +-
arch/arm/include/asm/fixmap.h | 16 ++--------------
arch/arm/include/asm/highmem.h | 1 +
arch/arm/mm/highmem.c | 27 +++++++++++++++++++++------
arch/arm/mm/mmu.c | 4 ++++
5 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/Documentation/arm/memory.txt b/Documentation/arm/memory.txt
index 4bfb9ff..a9fc59b 100644
--- a/Documentation/arm/memory.txt
+++ b/Documentation/arm/memory.txt
@@ -41,7 +41,7 @@ fffe8000 fffeffff DTCM mapping area for platforms with
fffe0000 fffe7fff ITCM mapping area for platforms with
ITCM mounted inside the CPU.

-fff00000 fffdffff Fixmap mapping region. Addresses provided
+fffc0000 ffdfffff Fixmap mapping region. Addresses provided
by fix_to_virt() will be located here.

ffc00000 ffefffff DMA memory mapping region. Memory returned
diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index be55ebc..74124b0 100644
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -1,20 +1,8 @@
#ifndef _ASM_FIXMAP_H
#define _ASM_FIXMAP_H

-/*
- * Nothing too fancy for now.
- *
- * On ARM we already have well known fixed virtual addresses imposed by
- * the architecture such as the vector page which is located at 0xffff0000,
- * therefore a second level page table is already allocated covering
- * 0xfff00000 upwards.
- *
- * The cache flushing code in proc-xscale.S uses the virtual area between
- * 0xfffe0000 and 0xfffeffff.
- */
-
-#define FIXADDR_START 0xfff00000UL
-#define FIXADDR_TOP 0xfffe0000UL
+#define FIXADDR_START 0xffc00000UL
+#define FIXADDR_TOP 0xffe00000UL
#define FIXADDR_SIZE (FIXADDR_TOP - FIXADDR_START)

#define FIX_KMAP_NR_PTES (FIXADDR_SIZE >> PAGE_SHIFT)
diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h
index 91b99ab..5355795 100644
--- a/arch/arm/include/asm/highmem.h
+++ b/arch/arm/include/asm/highmem.h
@@ -18,6 +18,7 @@
} while (0)

extern pte_t *pkmap_page_table;
+extern pte_t *fixmap_page_table;

extern void *kmap_high(struct page *page);
extern void kunmap_high(struct page *page);
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
index e05e8ad..45aeaac 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -18,6 +18,21 @@
#include <asm/tlbflush.h>
#include "mm.h"

+pte_t *fixmap_page_table;
+
+static inline void set_fixmap_pte(int idx, pte_t pte)
+{
+ unsigned long vaddr = __fix_to_virt(idx);
+ set_pte_ext(fixmap_page_table + idx, pte, 0);
+ local_flush_tlb_kernel_page(vaddr);
+}
+
+static inline pte_t get_fixmap_pte(unsigned long vaddr)
+{
+ unsigned long idx = __virt_to_fix(vaddr);
+ return *(fixmap_page_table + idx);
+}
+
void *kmap(struct page *page)
{
might_sleep();
@@ -69,14 +84,14 @@ void *kmap_atomic(struct page *page)
* With debugging enabled, kunmap_atomic forces that entry to 0.
* Make sure it was indeed properly unmapped.
*/
- BUG_ON(!pte_none(get_top_pte(vaddr)));
+ BUG_ON(!pte_none(*(fixmap_page_table + idx)));
#endif
/*
* When debugging is off, kunmap_atomic leaves the previous mapping
* in place, so the contained TLB flush ensures the TLB is updated
* with the new mapping.
*/
- set_top_pte(vaddr, mk_pte(page, kmap_prot));
+ set_fixmap_pte(idx, mk_pte(page, kmap_prot));

return (void *)vaddr;
}
@@ -95,7 +110,7 @@ void __kunmap_atomic(void *kvaddr)
__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(vaddr != __fix_to_virt(idx));
- set_top_pte(vaddr, __pte(0));
+ set_fixmap_pte(idx, __pte(0));
#else
(void) idx; /* to kill a warning */
#endif
@@ -119,9 +134,9 @@ void *kmap_atomic_pfn(unsigned long pfn)
idx = type + KM_TYPE_NR * smp_processor_id();
vaddr = __fix_to_virt(idx);
#ifdef CONFIG_DEBUG_HIGHMEM
- BUG_ON(!pte_none(get_top_pte(vaddr)));
+ BUG_ON(!pte_none(*(fixmap_page_table + idx)));
#endif
- set_top_pte(vaddr, pfn_pte(pfn, kmap_prot));
+ set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));

return (void *)vaddr;
}
@@ -133,5 +148,5 @@ struct page *kmap_atomic_to_page(const void *ptr)
if (vaddr < FIXADDR_START)
return virt_to_page(ptr);

- return pte_page(get_top_pte(vaddr));
+ return pte_page(get_fixmap_pte(vaddr));
}
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index b68c6b2..09c0a16 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -35,6 +35,7 @@
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
#include <asm/mach/pci.h>
+#include <asm/fixmap.h>

#include "mm.h"
#include "tcm.h"
@@ -1359,6 +1360,9 @@ static void __init kmap_init(void)
#ifdef CONFIG_HIGHMEM
pkmap_page_table = early_pte_alloc(pmd_off_k(PKMAP_BASE),
PKMAP_BASE, _PAGE_KERNEL_TABLE);
+
+ fixmap_page_table = early_pte_alloc(pmd_off_k(FIXADDR_START),
+ FIXADDR_START, _PAGE_KERNEL_TABLE);
#endif
}

--
1.9.0


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