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Date: Sun, 13 Apr 2014 21:25:05 +0800
From: Liu hua <sdu.liu@...wei.com>
To: Nicolas Pitre <nicolas.pitre@...aro.org>
CC: <linux@....linux.org.uk>, <will.deacon@....com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <wangnan0@...wei.com>,
<peifeiyue@...wei.com>, <liusdu@....com>,
<m.szyprowski@...sung.com>
Subject: Re: [PATCH v2 2/2] ARM : change fixmap mapping region to support
32 CPUs
On 2014/4/12 11:26, Nicolas Pitre wrote:
> On Fri, 11 Apr 2014, Liu Hua wrote:
>
>> 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@...wei.com>
>
> Comments below.
>
>> ---
>> Documentation/arm/memory.txt | 2 +-
>> arch/arm/include/asm/fixmap.h | 4 ++--
>> arch/arm/include/asm/highmem.h | 1 +
>> arch/arm/mm/highmem.c | 10 +++++-----
>> arch/arm/mm/mm.h | 7 +++++++
>> arch/arm/mm/mmu.c | 4 ++++
>> mm/highmem.c | 1 +
>> 7 files changed, 21 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/arm/memory.txt b/Documentation/arm/memory.txt
>> index 8a361c0..4bca737 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
>> +ffc00000 ffdfffff Fixmap mapping region. Addresses provided
>> by fix_to_virt() will be located here.
>>
>> ff000000 ffbfffff Reserved for future expansion of DMA
>> diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
>> index bbae919..014a70d 100644
>> --- a/arch/arm/include/asm/fixmap.h
>> +++ b/arch/arm/include/asm/fixmap.h
>> @@ -13,8 +13,8 @@
>> * 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_BEGIN 0
>> 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 21b9e1b..9bc8988 100644
>> --- a/arch/arm/mm/highmem.c
>> +++ b/arch/arm/mm/highmem.c
>> @@ -69,14 +69,14 @@ 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 +95,7 @@ void __kunmap_atomic(void *kvaddr)
>> __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
>> #ifdef CONFIG_DEBUG_HIGHMEM
>> BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
>> - set_top_pte(vaddr, __pte(0));
>> + set_fixmap_pte(idx, __pte(0));
>> #else
>> (void) idx; /* to kill a warning */
>> #endif
>> @@ -119,9 +119,9 @@ void *kmap_atomic_pfn(unsigned long pfn)
>> idx = type + KM_TYPE_NR * smp_processor_id();
>> vaddr = __fix_to_virt(FIX_KMAP_BEGIN + 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;
>> }
>> diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
>> index 7ea641b..3460d73 100644
>> --- a/arch/arm/mm/mm.h
>> +++ b/arch/arm/mm/mm.h
>> @@ -1,6 +1,7 @@
>> #ifdef CONFIG_MMU
>> #include <linux/list.h>
>> #include <linux/vmalloc.h>
>> +#include <asm/fixmap.h>
>>
>> /* the upper-most page table pointer */
>> extern pmd_t *top_pmd;
>> @@ -25,6 +26,12 @@ static inline void set_top_pte(unsigned long va, pte_t pte)
>> local_flush_tlb_kernel_page(va);
>> }
>>
>> +static inline void set_fixmap_pte(int idx, pte_t pte)
>> +{
>> + unsigned long vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
>> + set_pte_ext(fixmap_page_table + idx, pte, 0);
>> + local_flush_tlb_kernel_page(vaddr);
>> +}
>
> This has no other users than the code in highmem.c so it probably should
> live there.
>
> Other than that...
>
> Acked-by: Nicolas Pitre <nico@...aro.org>
>
> .
>
Hi Nicolas.
Sure, your suggestion made my patch looks better. How about that :
Thanks,
Liu Hua
-------------------------------------------------
Changes from v2:
moved new codes to highmem.c as more as possible.
unchanged Document/arm/memory.txt.
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
Acked-by: Nicolas Pitre <nico@...aro.org>
Signed-off-by: Liu Hua <sdu.liu@...wei.com>
---
arch/arm/include/asm/fixmap.h | 4 ++--
arch/arm/include/asm/highmem.h | 1 +
arch/arm/mm/highmem.c | 28 ++++++++++++++++++++++------
arch/arm/mm/mmu.c | 4 ++++
4 files changed, 29 insertions(+), 8 deletions(-)
diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index bbae919..014a70d 100644
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -13,8 +13,8 @@
* 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_BEGIN 0
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 21b9e1b..fa97896 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -18,6 +18,22 @@
#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(FIX_KMAP_BEGIN + 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);
+ idx -= FIX_KMAP_BEGIN;
+ return *(fixmap_page_table + idx);
+}
+
void *kmap(struct page *page)
{
might_sleep();
@@ -69,14 +85,14 @@ 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 +111,7 @@ void __kunmap_atomic(void *kvaddr)
__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
- set_top_pte(vaddr, __pte(0));
+ set_fixmap_pte(idx, __pte(0));
#else
(void) idx; /* to kill a warning */
#endif
@@ -119,9 +135,9 @@ void *kmap_atomic_pfn(unsigned long pfn)
idx = type + KM_TYPE_NR * smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + 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 +149,5 @@ 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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