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ARC: mm: preps ahead of HIGHMEM support

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Before we plug in highmem support, some of code needs to be ready for it
 - copy_user_highpage() needs to be using the kmap_atomic API
 - mk_pte() can't assume page_address()
 - do_page_fault() can't assume VMALLOC_END is end of kernel vaddr space

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta
2015-03-05 17:06:31 +05:30
parent d40846457f
commit 336e2136e1
3 changed files with 22 additions and 16 deletions
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16
arch/arc/mm/cache.c
View File

@@ -806,8 +806,8 @@ void flush_anon_page(struct vm_area_struct *vma, struct page *page,
void copy_user_highpage(struct page *to, struct page *from,
unsigned long u_vaddr, struct vm_area_struct *vma)
{
unsigned long kfrom = (unsigned long)page_address(from);
unsigned long kto = (unsigned long)page_address(to);
void *kfrom = kmap_atomic(from);
void *kto = kmap_atomic(to);
int clean_src_k_mappings = 0;
/*
@@ -817,13 +817,16 @@ void copy_user_highpage(struct page *to, struct page *from,
*
* Note that while @u_vaddr refers to DST page's userspace vaddr, it is
* equally valid for SRC page as well
*
* For !VIPT cache, all of this gets compiled out as
* addr_not_cache_congruent() is 0
*/
if (page_mapped(from) && addr_not_cache_congruent(kfrom, u_vaddr)) {
__flush_dcache_page(kfrom, u_vaddr);
__flush_dcache_page((unsigned long)kfrom, u_vaddr);
clean_src_k_mappings = 1;
}
copy_page((void *)kto, (void *)kfrom);
copy_page(kto, kfrom);
/*
* Mark DST page K-mapping as dirty for a later finalization by
@@ -840,11 +843,14 @@ void copy_user_highpage(struct page *to, struct page *from,
* sync the kernel mapping back to physical page
*/
if (clean_src_k_mappings) {
__flush_dcache_page(kfrom, kfrom);
__flush_dcache_page((unsigned long)kfrom, (unsigned long)kfrom);
set_bit(PG_dc_clean, &from->flags);
} else {
clear_bit(PG_dc_clean, &from->flags);
}
kunmap_atomic(kto);
kunmap_atomic(kfrom);
}
void clear_user_page(void *to, unsigned long u_vaddr, struct page *page)

13
arch/arc/mm/fault.c
View File

@@ -18,7 +18,14 @@
#include <asm/pgalloc.h>
#include <asm/mmu.h>
static int handle_vmalloc_fault(unsigned long address)
/*
* kernel virtual address is required to implement vmalloc/pkmap/fixmap
* Refer to asm/processor.h for System Memory Map
*
* It simply copies the PMD entry (pointer to 2nd level page table or hugepage)
* from swapper pgdir to task pgdir. The 2nd level table/page is thus shared
*/
noinline static int handle_kernel_vaddr_fault(unsigned long address)
{
/*
* Synchronize this task's top level page-table
@@ -72,8 +79,8 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
* only copy the information from the master page table,
* nothing more.
*/
if (address >= VMALLOC_START && address <= VMALLOC_END) {
ret = handle_vmalloc_fault(address);
if (address >= VMALLOC_START) {
ret = handle_kernel_vaddr_fault(address);
if (unlikely(ret))
goto bad_area_nosemaphore;
else