MIPS: Fix highmem.
Commit 351336929ccf222ae38ff0cb7a8dd5fd5c6236a0 (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>
diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c
index 4481656..2b1309b 100644
--- a/arch/mips/mm/highmem.c
+++ b/arch/mips/mm/highmem.c
@@ -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 @@
return addr;
}
+EXPORT_SYMBOL(__kmap);
void __kunmap(struct page *page)
{
@@ -22,6 +28,7 @@
return;
kunmap_high(page);
}
+EXPORT_SYMBOL(__kunmap);
/*
* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
@@ -48,11 +55,12 @@
#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 @@
pagefault_enable();
}
+EXPORT_SYMBOL(__kunmap_atomic);
/*
* This is the same as kmap_atomic() but can map memory that doesn't
@@ -92,7 +101,7 @@
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 @@
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);
+}