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ARM: expand fixmap region to 3MB 

With commit a05e54c103 ("ARM: 8031/2: change fixmap mapping region to
support 32 CPUs"), the fixmap region was expanded to 2MB, but it
precluded any other uses of the fixmap region. In order to support other
uses the fixmap region needs to be expanded beyond 2MB. Fortunately, the
adjacent 1MB range 0xffe00000-0xfff00000 is availabe.

Remove fixmap_page_table ptr and lookup the page table via the virtual
address so that the fixmap region can span more that one pmd. The 2nd
pmd is already created since it is shared with the vector page.

Signed-off-by: Rob Herring <robh@kernel.org>
[kees: fixed CONFIG_DEBUG_HIGHMEM get_fixmap() calls]
[kees: moved pte allocation outside of CONFIG_HIGHMEM]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
This commit is contained in:
Rob Herring 2014-07-02 02:01:15 -05:00 committed by Kees Cook
parent b615bbbff1
commit 836a241832
4 changed files with 13 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/arm/memory.txt
View File

@ -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.
ffc00000 ffdfffff Fixmap mapping region. Addresses provided
ffc00000 ffefffff Fixmap mapping region. Addresses provided
by fix_to_virt() will be located here.
fee00000 feffffff Mapping of PCI I/O space. This is a static

2
arch/arm/include/asm/fixmap.h
View File

@ -2,7 +2,7 @@
#define _ASM_FIXMAP_H
#define FIXADDR_START 0xffc00000UL
#define FIXADDR_END 0xffe00000UL
#define FIXADDR_END 0xfff00000UL
#define FIXADDR_TOP (FIXADDR_END - PAGE_SIZE)
#include <asm/kmap_types.h>

15
arch/arm/mm/highmem.c
View File

@ -18,19 +18,20 @@
#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);
pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
set_pte_ext(ptep, 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);
pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
return *ptep;
}
void *kmap(struct page *page)
@ -84,7 +85,7 @@ 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(*(fixmap_page_table + idx)));
BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
#endif
/*
* When debugging is off, kunmap_atomic leaves the previous mapping
@ -134,7 +135,7 @@ 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(*(fixmap_page_table + idx)));
BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
#endif
set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));

6
arch/arm/mm/mmu.c
View File

@ -1326,10 +1326,10 @@ 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
early_pte_alloc(pmd_off_k(FIXADDR_START), FIXADDR_START,
_PAGE_KERNEL_TABLE);
}
static void __init map_lowmem(void)