[PATCH 5.0 115/122] powerpc/mm/hash: Handle mmap_min_addr correctly in get_unmapped_area topdown search

Greg Kroah-Hartman
2019-05-06T14:38:30Z

From: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>

commit 3b4d07d2674f6b4a9281031f99d1f7efd325b16d upstream.

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: fba2369e6ceb ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/mm/slice.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -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_top
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_top
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_top
* 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(un
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;
}