csky: Fixup arch_get_unmapped_area() implementation

Current arch_get_unmapped_area() of abiv1 doesn't use standard kernel
api. After referring to the implementation of arch/arm, we implement
it with vm_unmapped_area() from linux/mm.h.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>

diff --git a/arch/csky/abiv1/inc/abi/page.h b/arch/csky/abiv1/inc/abi/page.h
index 6336e92..c864519 100644 (file)
--- a/arch/csky/abiv1/inc/abi/page.h
+++ b/arch/csky/abiv1/inc/abi/page.h
@@ -1,13 +1,14 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
 
-extern unsigned long shm_align_mask;
+#include <asm/shmparam.h>
+
 extern void flush_dcache_page(struct page *page);
 
 static inline unsigned long pages_do_alias(unsigned long addr1,
                                           unsigned long addr2)
 {
-       return (addr1 ^ addr2) & shm_align_mask;
+       return (addr1 ^ addr2) & (SHMLBA-1);
 }
 
 static inline void clear_user_page(void *addr, unsigned long vaddr,

diff --git a/arch/csky/abiv1/mmap.c b/arch/csky/abiv1/mmap.c
index b462fd5..6792aca 100644 (file)
--- a/arch/csky/abiv1/mmap.c
+++ b/arch/csky/abiv1/mmap.c
@@ -9,58 +9,63 @@
 #include <linux/random.h>
 #include <linux/io.h>
 
-unsigned long shm_align_mask = (0x4000 >> 1) - 1;   /* Sane caches */
+#define COLOUR_ALIGN(addr,pgoff)               \
+       ((((addr)+SHMLBA-1)&~(SHMLBA-1)) +      \
+        (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
 
-#define COLOUR_ALIGN(addr, pgoff) \
-       ((((addr) + shm_align_mask) & ~shm_align_mask) + \
-        (((pgoff) << PAGE_SHIFT) & shm_align_mask))
-
-unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
+/*
+ * We need to ensure that shared mappings are correctly aligned to
+ * avoid aliasing issues with VIPT caches.  We need to ensure that
+ * a specific page of an object is always mapped at a multiple of
+ * SHMLBA bytes.
+ *
+ * We unconditionally provide this function for all cases.
+ */
+unsigned long
+arch_get_unmapped_area(struct file *filp, unsigned long addr,
                unsigned long len, unsigned long pgoff, unsigned long flags)
 {
-       struct vm_area_struct *vmm;
-       int do_color_align;
+       struct mm_struct *mm = current->mm;
+       struct vm_area_struct *vma;
+       int do_align = 0;
+       struct vm_unmapped_area_info info;
+
+       /*
+        * We only need to do colour alignment if either the I or D
+        * caches alias.
+        */
+       do_align = filp || (flags & MAP_SHARED);
 
+       /*
+        * We enforce the MAP_FIXED case.
+        */
        if (flags & MAP_FIXED) {
-               /*
-                * We do not accept a shared mapping if it would violate
-                * cache aliasing constraints.
-                */
-               if ((flags & MAP_SHARED) &&
-                       ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
+               if (flags & MAP_SHARED &&
+                   (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
                        return -EINVAL;
                return addr;
        }
 
        if (len > TASK_SIZE)
                return -ENOMEM;
-       do_color_align = 0;
-       if (filp || (flags & MAP_SHARED))
-               do_color_align = 1;
+
        if (addr) {
-               if (do_color_align)
+               if (do_align)
                        addr = COLOUR_ALIGN(addr, pgoff);
                else
                        addr = PAGE_ALIGN(addr);
-               vmm = find_vma(current->mm, addr);
+
+               vma = find_vma(mm, addr);
                if (TASK_SIZE - len >= addr &&
-                               (!vmm || addr + len <= vmm->vm_start))
+                   (!vma || addr + len <= vm_start_gap(vma)))
                        return addr;
        }
-       addr = TASK_UNMAPPED_BASE;
-       if (do_color_align)
-               addr = COLOUR_ALIGN(addr, pgoff);
-       else
-               addr = PAGE_ALIGN(addr);
 
-       for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
-               /* At this point: (!vmm || addr < vmm->vm_end). */
-               if (TASK_SIZE - len < addr)
-                       return -ENOMEM;
-               if (!vmm || addr + len <= vmm->vm_start)
-                       return addr;
-               addr = vmm->vm_end;
-               if (do_color_align)
-                       addr = COLOUR_ALIGN(addr, pgoff);
-       }
+       info.flags = 0;
+       info.length = len;
+       info.low_limit = mm->mmap_base;
+       info.high_limit = TASK_SIZE;
+       info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+       info.align_offset = pgoff << PAGE_SHIFT;
+       return vm_unmapped_area(&info);
 }