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powerpc/mm/hash: Handle mmap_min_addr correctly in get_unmapped_area topdown search 

When doing top-down search the low_limit is not PAGE_SIZE but rather
max(PAGE_SIZE, mmap_min_addr). This handle cases in which mmap_min_addr >
PAGE_SIZE.

Fixes: fba2369e6c ("mm: use vm_unmapped_area() on powerpc architecture")
Reviewed-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
hifive-unleashed-5.1
Aneesh Kumar K.V 2019-02-26 10:09:35 +05:30 committed by Michael Ellerman
parent 5330367fa3
commit 3b4d07d267
1 changed files with 6 additions and 4 deletions
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10
arch/powerpc/mm/slice.c
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@ -32,6 +32,7 @@
#include <linux/export.h>
#include <linux/hugetlb.h>
#include <linux/sched/mm.h>
#include <linux/security.h>
#include <asm/mman.h>
#include <asm/mmu.h>
#include <asm/copro.h>
@ -377,6 +378,7 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm,
int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
unsigned long addr, found, prev;
struct vm_unmapped_area_info info;
unsigned long min_addr = max(PAGE_SIZE, mmap_min_addr);
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
@ -393,7 +395,7 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm,
if (high_limit > DEFAULT_MAP_WINDOW)
addr += mm->context.slb_addr_limit - DEFAULT_MAP_WINDOW;
while (addr > PAGE_SIZE) {
while (addr > min_addr) {
info.high_limit = addr;
if (!slice_scan_available(addr - 1, available, 0, &addr))
continue;
@ -405,8 +407,8 @@ static unsigned long slice_find_area_topdown(struct mm_struct *mm,
* Check if we need to reduce the range, or if we can
* extend it to cover the previous available slice.
*/
if (addr < PAGE_SIZE)
addr = PAGE_SIZE;
if (addr < min_addr)
addr = min_addr;
else if (slice_scan_available(addr - 1, available, 0, &prev)) {
addr = prev;
goto prev_slice;
@ -528,7 +530,7 @@ unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
addr = _ALIGN_UP(addr, page_size);
slice_dbg(" aligned addr=%lx\n", addr);
/* Ignore hint if it's too large or overlaps a VMA */
if (addr > high_limit - len ||
if (addr > high_limit - len || addr < mmap_min_addr ||
!slice_area_is_free(mm, addr, len))
addr = 0;
}