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: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index f7c7273..bd77135 100644 (file)
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -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);

diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index ae3b772..521fb2b 100644 (file)
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -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)

diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index d948e4e..af63f4a 100644 (file)
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -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