diff --git a/arch/s390/boot/boot.h b/arch/s390/boot/boot.h
index 5baa855c21cbc527334a179bd4e0fc6c0e7733ef..222c6886acf6f7d9cd6bbf149b16c63c85765263 100644
--- a/arch/s390/boot/boot.h
+++ b/arch/s390/boot/boot.h
@@ -54,6 +54,7 @@ unsigned long physmem_alloc_top_down(enum reserved_range_type type, unsigned lon
unsigned long physmem_alloc_range(enum reserved_range_type type, unsigned long size,
unsigned long align, unsigned long min, unsigned long max,
bool die_on_oom);
+unsigned long get_physmem_alloc_pos(void);
bool ipl_report_certs_intersects(unsigned long addr, unsigned long size,
unsigned long *intersection_start);
bool is_ipl_block_dump(void);
@@ -66,7 +67,8 @@ void verify_facilities(void);
void print_missing_facilities(void);
void sclp_early_setup_buffer(void);
void print_pgm_check_info(void);
-unsigned long get_random_base(void);
+unsigned long randomize_within_range(unsigned long size, unsigned long align,
+ unsigned long min, unsigned long max);
void setup_vmem(unsigned long asce_limit);
void __printf(1, 2) decompressor_printk(const char *fmt, ...);
void print_stacktrace(unsigned long sp);
diff --git a/arch/s390/boot/kaslr.c b/arch/s390/boot/kaslr.c
index 71f75f03f800d5ae4d1b3f6aaed13ad2c9e3edd6..90602101e2aee871e71ab9f23a83e33830211290 100644
--- a/arch/s390/boot/kaslr.c
+++ b/arch/s390/boot/kaslr.c
@@ -91,16 +91,108 @@ static int get_random(unsigned long limit, unsigned long *value)
return 0;
}
-unsigned long get_random_base(void)
+static void sort_reserved_ranges(struct reserved_range *res, unsigned long size)
{
- unsigned long vmlinux_size = vmlinux.image_size + vmlinux.bss_size;
- unsigned long minimal_pos = vmlinux.default_lma + vmlinux_size;
- unsigned long random;
+ struct reserved_range tmp;
+ int i, j;
- /* [vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size : physmem_info.usable] */
- if (get_random(physmem_info.usable - minimal_pos, &random))
- return 0;
+ for (i = 1; i < size; i++) {
+ tmp = res[i];
+ for (j = i - 1; j >= 0 && res[j].start > tmp.start; j--)
+ res[j + 1] = res[j];
+ res[j + 1] = tmp;
+ }
+}
+
+static unsigned long iterate_valid_positions(unsigned long size, unsigned long align,
+ unsigned long _min, unsigned long _max,
+ struct reserved_range *res, size_t res_count,
+ bool pos_count, unsigned long find_pos)
+{
+ unsigned long start, end, tmp_end, range_pos, pos = 0;
+ struct reserved_range *res_end = res + res_count;
+ struct reserved_range *skip_res;
+ int i;
+
+ align = max(align, 8UL);
+ _min = round_up(_min, align);
+ for_each_physmem_usable_range(i, &start, &end) {
+ if (_min >= end)
+ continue;
+ start = round_up(start, align);
+ if (start >= _max)
+ break;
+ start = max(_min, start);
+ end = min(_max, end);
+
+ while (start + size <= end) {
+ /* skip reserved ranges below the start */
+ while (res && res->end <= start) {
+ res++;
+ if (res >= res_end)
+ res = NULL;
+ }
+ skip_res = NULL;
+ tmp_end = end;
+ /* has intersecting reserved range */
+ if (res && res->start < end) {
+ skip_res = res;
+ tmp_end = res->start;
+ }
+ if (start + size <= tmp_end) {
+ range_pos = (tmp_end - start - size) / align + 1;
+ if (pos_count) {
+ pos += range_pos;
+ } else {
+ if (range_pos >= find_pos)
+ return start + (find_pos - 1) * align;
+ find_pos -= range_pos;
+ }
+ }
+ if (!skip_res)
+ break;
+ start = round_up(skip_res->end, align);
+ }
+ }
- return physmem_alloc_range(RR_VMLINUX, vmlinux_size, THREAD_SIZE,
- vmlinux.default_lma, minimal_pos + random, false);
+ return pos_count ? pos : 0;
+}
+
+/*
+ * Two types of decompressor memory allocations/reserves are considered
+ * differently.
+ *
+ * "Static" or "single" allocations are done via physmem_alloc_range() and
+ * physmem_reserve(), and they are listed in physmem_info.reserved[]. Each
+ * type of "static" allocation can only have one allocation per type and
+ * cannot have chains.
+ *
+ * On the other hand, "dynamic" or "repetitive" allocations are done via
+ * physmem_alloc_top_down(). These allocations are tightly packed together
+ * top down from the end of online memory. physmem_alloc_pos represents
+ * current position where those allocations start.
+ *
+ * Functions randomize_within_range() and iterate_valid_positions()
+ * only consider "dynamic" allocations by never looking above
+ * physmem_alloc_pos. "Static" allocations, however, are explicitly
+ * considered by checking the "res" (reserves) array. The first
+ * reserved_range of a "dynamic" allocation may also be checked along the
+ * way, but it will always be above the maximum value anyway.
+ */
+unsigned long randomize_within_range(unsigned long size, unsigned long align,
+ unsigned long min, unsigned long max)
+{
+ struct reserved_range res[RR_MAX];
+ unsigned long max_pos, pos;
+
+ memcpy(res, physmem_info.reserved, sizeof(res));
+ sort_reserved_ranges(res, ARRAY_SIZE(res));
+ max = min(max, get_physmem_alloc_pos());
+
+ max_pos = iterate_valid_positions(size, align, min, max, res, ARRAY_SIZE(res), true, 0);
+ if (!max_pos)
+ return 0;
+ if (get_random(max_pos, &pos))
+ return 0;
+ return iterate_valid_positions(size, align, min, max, res, ARRAY_SIZE(res), false, pos + 1);
}
diff --git a/arch/s390/boot/physmem_info.c b/arch/s390/boot/physmem_info.c
index 4ee9b73811420d069684008de126c7d8f69fcbf0..0cf79826eef99bdea136dab3b6ad2a0e4b4e80f6 100644
--- a/arch/s390/boot/physmem_info.c
+++ b/arch/s390/boot/physmem_info.c
@@ -321,3 +321,8 @@ unsigned long physmem_alloc_top_down(enum reserved_range_type type, unsigned lon
physmem_alloc_ranges = ranges_left;
return addr;
}
+
+unsigned long get_physmem_alloc_pos(void)
+{
+ return physmem_alloc_pos;
+}
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index 45c30c2b1a7a7107124ec91c3423472d457fa722..638a6cf8a075b037d9897caa57c068717228749a 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -316,7 +316,9 @@ void startup_kernel(void)
rescue_initrd(safe_addr, ident_map_size);
if (kaslr_enabled()) {
- vmlinux_lma = get_random_base();
+ vmlinux_lma = randomize_within_range(vmlinux.image_size + vmlinux.bss_size,
+ THREAD_SIZE, vmlinux.default_lma,
+ ident_map_size);
if (vmlinux_lma) {
__kaslr_offset = vmlinux_lma - vmlinux.default_lma;
offset_vmlinux_info(__kaslr_offset);