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Subject[PATCH v3 20/21] x86/kaslr: Make local variables 64-bit
Date
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>
---
arch/x86/boot/compressed/kaslr.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index c49d479245d0..38ecbf2e61c5 100644
--- 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) {
@@ -578,7 +579,7 @@ 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;
@@ -594,7 +595,7 @@ 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)
@@ -607,7 +608,7 @@ 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);
--
2.26.2
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