[PATCH v5 14/19] x86, kaslr: Add two functions which will be used later

Yinghai Lu
2015-03-18T07:28:21Z

From: Baoquan He <bhe@redhat.com>

Add two functions mem_min_overlap() and store_slot_info() which will be
used later.

Given a memory region mem_min_overlap will iterate all avoid region to
find the first one which overlap with it.

store_slot_info() calculates the slot info of passed in region and
store it into slot_areas[].

Signed-off-by: Baoquan He <bhe@redhat.com>
---
arch/x86/boot/compressed/aslr.c | 51 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)

diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index 33693c1..37dce4f 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -217,6 +217,40 @@ static bool mem_avoid_overlap(struct mem_vector *img)
return false;
}

+static unsigned long
+mem_min_overlap(struct mem_vector *img, struct mem_vector *out)
+{
+ int i;
+ struct setup_data *ptr;
+ unsigned long min = img->start + img->size;
+
+ for (i = 0; i < MEM_AVOID_MAX; i++) {
+ if (mem_overlaps(img, &mem_avoid[i]) &&
+ (mem_avoid[i].start < min)) {
+ *out = mem_avoid[i];
+ min = mem_avoid[i].start;
+ }
+ }
+
+ /* Check all entries in the setup_data linked list. */
+ ptr = (struct setup_data *)(unsigned long)real_mode->hdr.setup_data;
+ while (ptr) {
+ struct mem_vector avoid;
+
+ avoid.start = (unsigned long)ptr;
+ avoid.size = sizeof(*ptr) + ptr->len;
+
+ if (mem_overlaps(img, &avoid) && (avoid.start < min)) {
+ *out = avoid;
+ min = avoid.start;
+ }
+
+ ptr = (struct setup_data *)(unsigned long)ptr->next;
+ }
+
+ return min;
+}
+
static unsigned long slots[CONFIG_RANDOMIZE_BASE_MAX_OFFSET /
CONFIG_PHYSICAL_ALIGN];

@@ -233,6 +267,23 @@ static unsigned long slot_max;

static unsigned long slot_area_index;

+static void store_slot_info(struct mem_vector *region, unsigned long image_size)
+{
+ struct slot_area slot_area;
+
+ slot_area.addr = region->start;
+ if (image_size <= CONFIG_PHYSICAL_ALIGN)
+ slot_area.num = region->size / CONFIG_PHYSICAL_ALIGN;
+ else
+ slot_area.num = (region->size - image_size) /
+ CONFIG_PHYSICAL_ALIGN + 1;
+
+ if (slot_area.num > 0) {
+ slot_areas[slot_area_index++] = slot_area;
+ slot_max += slot_area.num;
+ }
+}
+
static void slots_append(unsigned long addr)
{
/* Overflowing the slots list should be impossible. */
--
1.8.4.5