Introduce sparc64 arch_mmap_hint() and define HAVE_ARCH_MMAP_HINT.
This is a preparatory patch, no functional change is introduced.

Signed-off-by: Kalesh Singh <kaleshsi...@google.com>
---

Changes in v2:
  - MAP_FIXED case is also handled in arch_mmap_hint() since this is just a
    special case of the hint addr being "enforced", per Yang Shi.
  - Consolidate error handling in arch_mmap_hint().

 arch/sparc/include/asm/pgtable_64.h |  1 +
 arch/sparc/kernel/sys_sparc_64.c    | 96 +++++++++++------------------
 2 files changed, 37 insertions(+), 60 deletions(-)

diff --git a/arch/sparc/include/asm/pgtable_64.h 
b/arch/sparc/include/asm/pgtable_64.h
index 2b7f358762c1..f24a4eb2777b 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -1148,6 +1148,7 @@ static inline bool pte_access_permitted(pte_t pte, bool 
write)
  */
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#define HAVE_ARCH_MMAP_HINT
 
 /* We provide a special get_unmapped_area for framebuffer mmaps to try and use
  * the largest alignment possible such that larget PTEs can be used.
diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index c5a284df7b41..e44d55b30a84 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -98,17 +98,19 @@ static unsigned long get_align_mask(struct file *filp, 
unsigned long flags)
        return 0;
 }
 
-unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, 
unsigned long len, unsigned long pgoff, unsigned long flags, vm_flags_t 
vm_flags)
+unsigned long arch_mmap_hint(struct file *filp, unsigned long addr,
+                            unsigned long len, unsigned long pgoff,
+                            unsigned long flags)
 {
-       struct mm_struct *mm = current->mm;
-       struct vm_area_struct * vma;
-       unsigned long task_size = TASK_SIZE;
-       int do_color_align;
-       struct vm_unmapped_area_info info = {};
-       bool file_hugepage = false;
+       unsigned long task_size;
+       bool do_color_align;
+       bool file_hugepage;
 
-       if (filp && is_file_hugepages(filp))
-               file_hugepage = true;
+       task_size = test_thread_flag(TIF_32BIT) ? STACK_TOP32 : TASK_SIZE;
+       if (unlikely(len > task_size || len >= VA_EXCLUDE_START))
+               return -ENOMEM;
+
+       file_hugepage = filp && is_file_hugepages(filp);
 
        if (flags & MAP_FIXED) {
                /* We do not accept a shared mapping if it would violate
@@ -120,26 +122,29 @@ unsigned long arch_get_unmapped_area(struct file *filp, 
unsigned long addr, unsi
                return addr;
        }
 
-       if (test_thread_flag(TIF_32BIT))
-               task_size = STACK_TOP32;
-       if (unlikely(len > task_size || len >= VA_EXCLUDE_START))
-               return -ENOMEM;
+       do_color_align = (filp || (flags & MAP_SHARED)) && !file_hugepage;
 
-       do_color_align = 0;
-       if ((filp || (flags & MAP_SHARED)) && !file_hugepage)
-               do_color_align = 1;
+       if (do_color_align)
+               addr = COLOR_ALIGN(addr, pgoff);
+       else
+               addr = PAGE_ALIGN(addr);
 
-       if (addr) {
-               if (do_color_align)
-                       addr = COLOR_ALIGN(addr, pgoff);
-               else
-                       addr = PAGE_ALIGN(addr);
+       return generic_mmap_hint(filp, addr, len, pgoff, flags);
+}
 
-               vma = find_vma(mm, addr);
-               if (task_size - len >= addr &&
-                   (!vma || addr + len <= vm_start_gap(vma)))
-                       return addr;
-       }
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, 
unsigned long len,
+                                    unsigned long pgoff, unsigned long flags, 
vm_flags_t vm_flags)
+{
+       struct vm_unmapped_area_info info = {};
+       unsigned long task_size;
+       bool file_hugepage;
+
+       addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+       if (addr)
+               return addr;
+
+       task_size = test_thread_flag(TIF_32BIT) ? STACK_TOP32 : TASK_SIZE;
+       file_hugepage = filp && is_file_hugepages(filp);
 
        info.length = len;
        info.low_limit = TASK_UNMAPPED_BASE;
@@ -164,49 +169,20 @@ arch_get_unmapped_area_topdown(struct file *filp, const 
unsigned long addr0,
                          const unsigned long len, const unsigned long pgoff,
                          const unsigned long flags, vm_flags_t vm_flags)
 {
-       struct vm_area_struct *vma;
        struct mm_struct *mm = current->mm;
-       unsigned long task_size = STACK_TOP32;
        unsigned long addr = addr0;
-       int do_color_align;
        struct vm_unmapped_area_info info = {};
-       bool file_hugepage = false;
+       bool file_hugepage;
 
        /* This should only ever run for 32-bit processes.  */
        BUG_ON(!test_thread_flag(TIF_32BIT));
 
-       if (filp && is_file_hugepages(filp))
-               file_hugepage = true;
-
-       if (flags & MAP_FIXED) {
-               /* We do not accept a shared mapping if it would violate
-                * cache aliasing constraints.
-                */
-               if (!file_hugepage && (flags & MAP_SHARED) &&
-                   ((addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)))
-                       return -EINVAL;
-               return addr;
-       }
-
-       if (unlikely(len > task_size))
-               return -ENOMEM;
-
-       do_color_align = 0;
-       if ((filp || (flags & MAP_SHARED)) && !file_hugepage)
-               do_color_align = 1;
-
        /* requesting a specific address */
-       if (addr) {
-               if (do_color_align)
-                       addr = COLOR_ALIGN(addr, pgoff);
-               else
-                       addr = PAGE_ALIGN(addr);
+       addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+       if (addr)
+               return addr;
 
-               vma = find_vma(mm, addr);
-               if (task_size - len >= addr &&
-                   (!vma || addr + len <= vm_start_gap(vma)))
-                       return addr;
-       }
+       file_hugepage = filp && is_file_hugepages(filp);
 
        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
        info.length = len;
-- 
2.47.0.338.g60cca15819-goog


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