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MIPS: Fix highmem.

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Commit 351336929c (kernel.org) rsp.
b3594a089f1c17ff919f8f78505c3f20e1f6f8ce (linux-mips.org):

> From: Chris Dearman <chris@mips.com>
> Date: Wed, 19 Sep 2007 00:58:24 +0100
> Subject: [PATCH] [MIPS] Allow setting of the cache attribute at run time.
>
> Slightly tacky, but there is a precedent in the sparc archirecture code.

introduces the variable _page_cachable_default, which defaults to zero and.
is used to create the prototype PTE for __kmap_atomic in
arch/mips/mm/init.c:kmap_init before initialization in
arch/mips/mm/c-r4k.c:coherency_setup, so the default value of 0 will be
used as the CCA of kmap atomic pages which on many processors is not a
defined CCA value and may result in writes to kmap_atomic pages getting
corrupted.  Debugged by Jon Fraser (jfraser@broadcom.com).

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle
2009-04-25 11:25:34 +02:00
parent 0b54352600
commit bb86bf28ae
4 changed files with 26 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
arch/mips/mm/highmem.c
View File

@@ -1,7 +1,12 @@
#include <linux/module.h>
#include <linux/highmem.h>
#include <asm/fixmap.h>
#include <asm/tlbflush.h>
static pte_t *kmap_pte;
unsigned long highstart_pfn, highend_pfn;
void *__kmap(struct page *page)
{
void *addr;
@@ -14,6 +19,7 @@ void *__kmap(struct page *page)
return addr;
}
EXPORT_SYMBOL(__kmap);
void __kunmap(struct page *page)
{
@@ -22,6 +28,7 @@ void __kunmap(struct page *page)
return;
kunmap_high(page);
}
EXPORT_SYMBOL(__kunmap);
/*
* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
@@ -48,11 +55,12 @@ void *__kmap_atomic(struct page *page, enum km_type type)
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(*(kmap_pte - idx)));
#endif
set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
local_flush_tlb_one((unsigned long)vaddr);
return (void*) vaddr;
}
EXPORT_SYMBOL(__kmap_atomic);
void __kunmap_atomic(void *kvaddr, enum km_type type)
{
@@ -77,6 +85,7 @@ void __kunmap_atomic(void *kvaddr, enum km_type type)
pagefault_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);
/*
* This is the same as kmap_atomic() but can map memory that doesn't
@@ -92,7 +101,7 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
debug_kmap_atomic(type);
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
flush_tlb_one(vaddr);
return (void*) vaddr;
@@ -111,7 +120,11 @@ struct page *__kmap_atomic_to_page(void *ptr)
return pte_page(*pte);
}
EXPORT_SYMBOL(__kmap);
EXPORT_SYMBOL(__kunmap);
EXPORT_SYMBOL(__kmap_atomic);
EXPORT_SYMBOL(__kunmap_atomic);
void __init kmap_init(void)
{
unsigned long kmap_vstart;
/* cache the first kmap pte */
kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
}