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Commit 336e2136 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: mm: preps ahead of HIGHMEM support 



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: default avatarAlexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent d4084645

arch/arc/include/asm/pgtable.h

+1 −8
Original line number Diff line number Diff line
@@ -270,13 +270,7 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep) 
		(unsigned long)(((pte_val(x) - CONFIG_LINUX_LINK_BASE) >> \

				PAGE_SHIFT)))



#define mk_pte(page, pgprot)						\

({									\

	pte_t pte;							\

	pte_val(pte) = __pa(page_address(page)) + pgprot_val(pgprot);	\

	pte;								\

})



#define mk_pte(page, prot)	pfn_pte(page_to_pfn(page), prot)

#define pte_pfn(pte)		(pte_val(pte) >> PAGE_SHIFT)

#define pfn_pte(pfn, prot)	(__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))

#define __pte_index(addr)	(((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
@@ -360,7 +354,6 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, 
#define pgd_offset_fast(mm, addr)	pgd_offset(mm, addr)

#endif



extern void paging_init(void);

extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE);

void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,

		      pte_t *ptep);

arch/arc/mm/cache.c

+11 −5
Original line number Diff line number Diff line
@@ -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)

arch/arc/mm/fault.c

+10 −3
Original line number Diff line number Diff line
@@ -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