[PATCH v4 06/10] powerpc/mm: Use generic_get_unmapped_area() and call it from arch_get_unmapped_area()

Christophe Leroy
2021-12-08T17:18:31Z

Use the generic version of arch_get_unmapped_area() which
is now available at all time instead of its copy
radix__arch_get_unmapped_area()

Instead of setting mm->get_unmapped_area() to either
arch_get_unmapped_area() or generic_get_unmapped_area(),
always set it to arch_get_unmapped_area() and call
generic_get_unmapped_area() from there when radix is enabled.

Do the same with radix__arch_get_unmapped_area_topdown()

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/mm/mmap.c | 127 ++---------------------------------------
1 file changed, 6 insertions(+), 121 deletions(-)

diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
index 9b0d6e395bc0..46781d0103d1 100644
--- a/arch/powerpc/mm/mmap.c
+++ b/arch/powerpc/mm/mmap.c
@@ -81,115 +81,15 @@ static inline unsigned long mmap_base(unsigned long rnd,
}

#ifdef HAVE_ARCH_UNMAPPED_AREA
-#ifdef CONFIG_PPC_RADIX_MMU
-/*
- * Same function as generic code used only for radix, because we don't need to overload
- * the generic one. But we will have to duplicate, because hash select
- * HAVE_ARCH_UNMAPPED_AREA
- */
-static unsigned long
-radix__arch_get_unmapped_area(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;
- int fixed = (flags & MAP_FIXED);
- unsigned long high_limit;
- struct vm_unmapped_area_info info;
-
- high_limit = DEFAULT_MAP_WINDOW;
- if (addr >= high_limit || (fixed && (addr + len > high_limit)))
- high_limit = TASK_SIZE;
-
- if (len > high_limit)
- return -ENOMEM;
-
- if (fixed) {
- if (addr > high_limit - len)
- return -ENOMEM;
- return addr;
- }
-
- if (addr) {
- addr = PAGE_ALIGN(addr);
- vma = find_vma(mm, addr);
- if (high_limit - len >= addr && addr >= mmap_min_addr &&
- (!vma || addr + len <= vm_start_gap(vma)))
- return addr;
- }
-
- info.flags = 0;
- info.length = len;
- info.low_limit = mm->mmap_base;
- info.high_limit = high_limit;
- info.align_mask = 0;
-
- return vm_unmapped_area(&info);
-}
-
-static unsigned long
-radix__arch_get_unmapped_area_topdown(struct file *filp,
- const unsigned long addr0,
- const unsigned long len,
- const unsigned long pgoff,
- const unsigned long flags)
-{
- struct vm_area_struct *vma;
- struct mm_struct *mm = current->mm;
- unsigned long addr = addr0;
- int fixed = (flags & MAP_FIXED);
- unsigned long high_limit;
- struct vm_unmapped_area_info info;
-
- high_limit = DEFAULT_MAP_WINDOW;
- if (addr >= high_limit || (fixed && (addr + len > high_limit)))
- high_limit = TASK_SIZE;
-
- if (len > high_limit)
- return -ENOMEM;
-
- if (fixed) {
- if (addr > high_limit - len)
- return -ENOMEM;
- return addr;
- }
-
- if (addr) {
- addr = PAGE_ALIGN(addr);
- vma = find_vma(mm, addr);
- if (high_limit - len >= addr && addr >= mmap_min_addr &&
- (!vma || addr + len <= vm_start_gap(vma)))
- return addr;
- }
-
- info.flags = VM_UNMAPPED_AREA_TOPDOWN;
- info.length = len;
- info.low_limit = max(PAGE_SIZE, mmap_min_addr);
- info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
- info.align_mask = 0;
-
- addr = vm_unmapped_area(&info);
- if (!(addr & ~PAGE_MASK))
- return addr;
- VM_BUG_ON(addr != -ENOMEM);
-
- /*
- * A failed mmap() very likely causes application failure,
- * so fall back to the bottom-up function here. This scenario
- * can happen with large stack limits and large mmap()
- * allocations.
- */
- return radix__arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
-}
-#endif
-
unsigned long arch_get_unmapped_area(struct file *filp,
unsigned long addr,
unsigned long len,
unsigned long pgoff,
unsigned long flags)
{
+ if (radix_enabled())
+ return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
+
#ifdef CONFIG_PPC_64S_HASH_MMU
return slice_get_unmapped_area(addr, len, flags,
mm_ctx_user_psize(&current->mm->context), 0);
@@ -204,6 +104,9 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
const unsigned long pgoff,
const unsigned long flags)
{
+ if (radix_enabled())
+ return generic_get_unmapped_area_topdown(filp, addr0, len, pgoff, flags);
+
#ifdef CONFIG_PPC_64S_HASH_MMU
return slice_get_unmapped_area(addr0, len, flags,
mm_ctx_user_psize(&current->mm->context), 1);
@@ -213,21 +116,6 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
}
#endif /* HAVE_ARCH_UNMAPPED_AREA */

-static void radix__arch_pick_mmap_layout(struct mm_struct *mm,
- unsigned long random_factor,
- struct rlimit *rlim_stack)
-{
-#ifdef CONFIG_PPC_RADIX_MMU
- if (mmap_is_legacy(rlim_stack)) {
- mm->mmap_base = TASK_UNMAPPED_BASE;
- mm->get_unmapped_area = radix__arch_get_unmapped_area;
- } else {
- mm->mmap_base = mmap_base(random_factor, rlim_stack);
- mm->get_unmapped_area = radix__arch_get_unmapped_area_topdown;
- }
-#endif
-}
-
/*
* This function, called very early during the creation of a new
* process VM image, sets up which VM layout function to use:
@@ -239,9 +127,6 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
if (current->flags & PF_RANDOMIZE)
random_factor = arch_mmap_rnd();

- if (radix_enabled())
- return radix__arch_pick_mmap_layout(mm, random_factor,
- rlim_stack);
/*
* Fall back to the standard layout if the personality
* bit is set, or if the expected stack growth is unlimited:
--
2.33.1