Commit bb86bf28 authored by Ralf Baechle's avatar Ralf Baechle
Browse files

MIPS: Fix highmem. 



Commit 35133692 (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: default avatarRalf Baechle <ralf@linux-mips.org>
parent 0b543526

arch/mips/include/asm/fixmap.h

+3 −0
Original line number Diff line number Diff line
@@ -108,6 +108,9 @@ static inline unsigned long virt_to_fix(const unsigned long vaddr) 
	return __virt_to_fix(vaddr);

}



#define kmap_get_fixmap_pte(vaddr)					\

	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))



/*

 * Called from pgtable_init()

 */

arch/mips/include/asm/highmem.h

+4 −2
Original line number Diff line number Diff line
@@ -30,8 +30,6 @@ 
/* declarations for highmem.c */

extern unsigned long highstart_pfn, highend_pfn;



extern pte_t *kmap_pte;

extern pgprot_t kmap_prot;

extern pte_t *pkmap_page_table;



/*
@@ -62,6 +60,10 @@ extern struct page *__kmap_atomic_to_page(void *ptr); 


#define flush_cache_kmaps()	flush_cache_all()



extern void kmap_init(void);



#define kmap_prot PAGE_KERNEL



#endif /* __KERNEL__ */



#endif /* _ASM_HIGHMEM_H */

arch/mips/mm/highmem.c

+19 −6
Original line number Diff line number Diff line 
#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);

}

arch/mips/mm/init.c

+0 −26
Original line number Diff line number Diff line
@@ -104,14 +104,6 @@ unsigned long setup_zero_pages(void) 
	return 1UL << order;

}



/*

 * These are almost like kmap_atomic / kunmap_atmic except they take an

 * additional address argument as the hint.

 */



#define kmap_get_fixmap_pte(vaddr)					\

	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))



#ifdef CONFIG_MIPS_MT_SMTC

static pte_t *kmap_coherent_pte;

static void __init kmap_coherent_init(void)
@@ -264,24 +256,6 @@ void copy_from_user_page(struct vm_area_struct *vma, 
	}

}



#ifdef CONFIG_HIGHMEM

unsigned long highstart_pfn, highend_pfn;



pte_t *kmap_pte;

pgprot_t kmap_prot;



static 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);



	kmap_prot = PAGE_KERNEL;

}

#endif /* CONFIG_HIGHMEM */



void __init fixrange_init(unsigned long start, unsigned long end,

	pgd_t *pgd_base)

{

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