x86/kaslr: Make local variables 64-bit

Change the type of local variables/fields that store mem_vector
addresses to u64 to make it less likely that 32-bit overflow will cause
issues on 32-bit.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200728225722.67457-21-nivedita@alum.mit.edu

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index db8589c..80cdd20 100644 (file)
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -461,7 +461,7 @@ static bool mem_avoid_overlap(struct mem_vector *img,
 {
        int i;
        struct setup_data *ptr;
-       unsigned long earliest = img->start + img->size;
+       u64 earliest = img->start + img->size;
        bool is_overlapping = false;
 
        for (i = 0; i < MEM_AVOID_MAX; i++) {
@@ -506,7 +506,7 @@ static bool mem_avoid_overlap(struct mem_vector *img,
 }
 
 struct slot_area {
-       unsigned long addr;
+       u64 addr;
        unsigned long num;
 };
 
@@ -537,7 +537,8 @@ static void store_slot_info(struct mem_vector *region, unsigned long image_size)
 static void
 process_gb_huge_pages(struct mem_vector *region, unsigned long image_size)
 {
-       unsigned long pud_start, pud_end, gb_huge_pages;
+       u64 pud_start, pud_end;
+       unsigned long gb_huge_pages;
        struct mem_vector tmp;
 
        if (!IS_ENABLED(CONFIG_X86_64) || !max_gb_huge_pages) {
@@ -579,7 +580,7 @@ process_gb_huge_pages(struct mem_vector *region, unsigned long image_size)
        }
 }
 
-static unsigned long slots_fetch_random(void)
+static u64 slots_fetch_random(void)
 {
        unsigned long slot;
        unsigned int i;
@@ -595,7 +596,7 @@ static unsigned long slots_fetch_random(void)
                        slot -= slot_areas[i].num;
                        continue;
                }
-               return slot_areas[i].addr + slot * CONFIG_PHYSICAL_ALIGN;
+               return slot_areas[i].addr + ((u64)slot * CONFIG_PHYSICAL_ALIGN);
        }
 
        if (i == slot_area_index)
@@ -608,7 +609,7 @@ static void __process_mem_region(struct mem_vector *entry,
                                 unsigned long image_size)
 {
        struct mem_vector region, overlap;
-       unsigned long region_end;
+       u64 region_end;
 
        /* Enforce minimum and memory limit. */
        region.start = max_t(u64, entry->start, minimum);