summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/boot/compressed/kaslr.c238
-rw-r--r--arch/x86/boot/compressed/misc.h4
2 files changed, 107 insertions, 135 deletions
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index dde7cb3724df..877970d76249 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -36,6 +36,10 @@
#define STATIC
#include <linux/decompress/mm.h>
+#define _SETUP
+#include <asm/setup.h> /* For COMMAND_LINE_SIZE */
+#undef _SETUP
+
#ifdef CONFIG_X86_5LEVEL
unsigned int __pgtable_l5_enabled;
unsigned int pgdir_shift __ro_after_init = 39;
@@ -87,8 +91,11 @@ static unsigned long get_boot_seed(void)
static bool memmap_too_large;
-/* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */
-static unsigned long long mem_limit = ULLONG_MAX;
+/*
+ * Store memory limit: MAXMEM on 64-bit and KERNEL_IMAGE_SIZE on 32-bit.
+ * It may be reduced by "mem=nn[KMG]" or "memmap=nn[KMG]" command line options.
+ */
+static u64 mem_limit;
/* Number of immovable memory regions */
static int num_immovable_mem;
@@ -131,8 +138,7 @@ enum parse_mode {
};
static int
-parse_memmap(char *p, unsigned long long *start, unsigned long long *size,
- enum parse_mode mode)
+parse_memmap(char *p, u64 *start, u64 *size, enum parse_mode mode)
{
char *oldp;
@@ -162,7 +168,7 @@ parse_memmap(char *p, unsigned long long *start, unsigned long long *size,
*/
*size = 0;
} else {
- unsigned long long flags;
+ u64 flags;
/*
* efi_fake_mem=nn@ss:attr the attr specifies
@@ -201,7 +207,7 @@ static void mem_avoid_memmap(enum parse_mode mode, char *str)
while (str && (i < MAX_MEMMAP_REGIONS)) {
int rc;
- unsigned long long start, size;
+ u64 start, size;
char *k = strchr(str, ',');
if (k)
@@ -214,7 +220,7 @@ static void mem_avoid_memmap(enum parse_mode mode, char *str)
if (start == 0) {
/* Store the specified memory limit if size > 0 */
- if (size > 0)
+ if (size > 0 && size < mem_limit)
mem_limit = size;
continue;
@@ -261,15 +267,15 @@ static void parse_gb_huge_pages(char *param, char *val)
static void handle_mem_options(void)
{
char *args = (char *)get_cmd_line_ptr();
- size_t len = strlen((char *)args);
+ size_t len;
char *tmp_cmdline;
char *param, *val;
u64 mem_size;
- if (!strstr(args, "memmap=") && !strstr(args, "mem=") &&
- !strstr(args, "hugepages"))
+ if (!args)
return;
+ len = strnlen(args, COMMAND_LINE_SIZE-1);
tmp_cmdline = malloc(len + 1);
if (!tmp_cmdline)
error("Failed to allocate space for tmp_cmdline");
@@ -284,14 +290,12 @@ static void handle_mem_options(void)
while (*args) {
args = next_arg(args, &param, &val);
/* Stop at -- */
- if (!val && strcmp(param, "--") == 0) {
- warn("Only '--' specified in cmdline");
- goto out;
- }
+ if (!val && strcmp(param, "--") == 0)
+ break;
if (!strcmp(param, "memmap")) {
mem_avoid_memmap(PARSE_MEMMAP, val);
- } else if (strstr(param, "hugepages")) {
+ } else if (IS_ENABLED(CONFIG_X86_64) && strstr(param, "hugepages")) {
parse_gb_huge_pages(param, val);
} else if (!strcmp(param, "mem")) {
char *p = val;
@@ -300,21 +304,23 @@ static void handle_mem_options(void)
continue;
mem_size = memparse(p, &p);
if (mem_size == 0)
- goto out;
+ break;
- mem_limit = mem_size;
+ if (mem_size < mem_limit)
+ mem_limit = mem_size;
} else if (!strcmp(param, "efi_fake_mem")) {
mem_avoid_memmap(PARSE_EFI, val);
}
}
-out:
free(tmp_cmdline);
return;
}
/*
- * In theory, KASLR can put the kernel anywhere in the range of [16M, 64T).
+ * In theory, KASLR can put the kernel anywhere in the range of [16M, MAXMEM)
+ * on 64-bit, and [16M, KERNEL_IMAGE_SIZE) on 32-bit.
+ *
* The mem_avoid array is used to store the ranges that need to be avoided
* when KASLR searches for an appropriate random address. We must avoid any
* regions that are unsafe to overlap with during decompression, and other
@@ -392,8 +398,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
{
unsigned long init_size = boot_params->hdr.init_size;
u64 initrd_start, initrd_size;
- u64 cmd_line, cmd_line_size;
- char *ptr;
+ unsigned long cmd_line, cmd_line_size;
/*
* Avoid the region that is unsafe to overlap during
@@ -414,16 +419,15 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
/* No need to set mapping for initrd, it will be handled in VO. */
/* Avoid kernel command line. */
- cmd_line = (u64)boot_params->ext_cmd_line_ptr << 32;
- cmd_line |= boot_params->hdr.cmd_line_ptr;
+ cmd_line = get_cmd_line_ptr();
/* Calculate size of cmd_line. */
- ptr = (char *)(unsigned long)cmd_line;
- for (cmd_line_size = 0; ptr[cmd_line_size++];)
- ;
- mem_avoid[MEM_AVOID_CMDLINE].start = cmd_line;
- mem_avoid[MEM_AVOID_CMDLINE].size = cmd_line_size;
- add_identity_map(mem_avoid[MEM_AVOID_CMDLINE].start,
- mem_avoid[MEM_AVOID_CMDLINE].size);
+ if (cmd_line) {
+ cmd_line_size = strnlen((char *)cmd_line, COMMAND_LINE_SIZE-1) + 1;
+ mem_avoid[MEM_AVOID_CMDLINE].start = cmd_line;
+ mem_avoid[MEM_AVOID_CMDLINE].size = cmd_line_size;
+ add_identity_map(mem_avoid[MEM_AVOID_CMDLINE].start,
+ mem_avoid[MEM_AVOID_CMDLINE].size);
+ }
/* Avoid boot parameters. */
mem_avoid[MEM_AVOID_BOOTPARAMS].start = (unsigned long)boot_params;
@@ -454,7 +458,7 @@ 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++) {
@@ -499,18 +503,16 @@ static bool mem_avoid_overlap(struct mem_vector *img,
}
struct slot_area {
- unsigned long addr;
- int num;
+ u64 addr;
+ unsigned long num;
};
#define MAX_SLOT_AREA 100
static struct slot_area slot_areas[MAX_SLOT_AREA];
-
+static unsigned int slot_area_index;
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;
@@ -519,13 +521,10 @@ static void store_slot_info(struct mem_vector *region, unsigned long image_size)
return;
slot_area.addr = region->start;
- slot_area.num = (region->size - image_size) /
- CONFIG_PHYSICAL_ALIGN + 1;
+ slot_area.num = 1 + (region->size - image_size) / CONFIG_PHYSICAL_ALIGN;
- if (slot_area.num > 0) {
- slot_areas[slot_area_index++] = slot_area;
- slot_max += slot_area.num;
- }
+ slot_areas[slot_area_index++] = slot_area;
+ slot_max += slot_area.num;
}
/*
@@ -535,57 +534,53 @@ 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 addr, size = 0;
+ u64 pud_start, pud_end;
+ unsigned long gb_huge_pages;
struct mem_vector tmp;
- int i = 0;
- if (!max_gb_huge_pages) {
+ if (!IS_ENABLED(CONFIG_X86_64) || !max_gb_huge_pages) {
store_slot_info(region, image_size);
return;
}
- addr = ALIGN(region->start, PUD_SIZE);
- /* Did we raise the address above the passed in memory entry? */
- if (addr < region->start + region->size)
- size = region->size - (addr - region->start);
-
- /* Check how many 1GB huge pages can be filtered out: */
- while (size > PUD_SIZE && max_gb_huge_pages) {
- size -= PUD_SIZE;
- max_gb_huge_pages--;
- i++;
- }
+ /* Are there any 1GB pages in the region? */
+ pud_start = ALIGN(region->start, PUD_SIZE);
+ pud_end = ALIGN_DOWN(region->start + region->size, PUD_SIZE);
/* No good 1GB huge pages found: */
- if (!i) {
+ if (pud_start >= pud_end) {
store_slot_info(region, image_size);
return;
}
- /*
- * Skip those 'i'*1GB good huge pages, and continue checking and
- * processing the remaining head or tail part of the passed region
- * if available.
- */
-
- if (addr >= region->start + image_size) {
+ /* Check if the head part of the region is usable. */
+ if (pud_start >= region->start + image_size) {
tmp.start = region->start;
- tmp.size = addr - region->start;
+ tmp.size = pud_start - region->start;
store_slot_info(&tmp, image_size);
}
- size = region->size - (addr - region->start) - i * PUD_SIZE;
- if (size >= image_size) {
- tmp.start = addr + i * PUD_SIZE;
- tmp.size = size;
+ /* Skip the good 1GB pages. */
+ gb_huge_pages = (pud_end - pud_start) >> PUD_SHIFT;
+ if (gb_huge_pages > max_gb_huge_pages) {
+ pud_end = pud_start + (max_gb_huge_pages << PUD_SHIFT);
+ max_gb_huge_pages = 0;
+ } else {
+ max_gb_huge_pages -= gb_huge_pages;
+ }
+
+ /* Check if the tail part of the region is usable. */
+ if (region->start + region->size >= pud_end + image_size) {
+ tmp.start = pud_end;
+ tmp.size = region->start + region->size - pud_end;
store_slot_info(&tmp, image_size);
}
}
-static unsigned long slots_fetch_random(void)
+static u64 slots_fetch_random(void)
{
unsigned long slot;
- int i;
+ unsigned int i;
/* Handle case of no slots stored. */
if (slot_max == 0)
@@ -598,7 +593,7 @@ 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)
@@ -611,49 +606,23 @@ static void __process_mem_region(struct mem_vector *entry,
unsigned long image_size)
{
struct mem_vector region, overlap;
- unsigned long start_orig, end;
- struct mem_vector cur_entry;
-
- /* On 32-bit, ignore entries entirely above our maximum. */
- if (IS_ENABLED(CONFIG_X86_32) && entry->start >= KERNEL_IMAGE_SIZE)
- return;
+ u64 region_end;
- /* Ignore entries entirely below our minimum. */
- if (entry->start + entry->size < minimum)
- return;
-
- /* Ignore entries above memory limit */
- end = min(entry->size + entry->start, mem_limit);
- if (entry->start >= end)
- return;
- cur_entry.start = entry->start;
- cur_entry.size = end - entry->start;
-
- region.start = cur_entry.start;
- region.size = cur_entry.size;
+ /* Enforce minimum and memory limit. */
+ region.start = max_t(u64, entry->start, minimum);
+ region_end = min(entry->start + entry->size, mem_limit);
/* Give up if slot area array is full. */
while (slot_area_index < MAX_SLOT_AREA) {
- start_orig = region.start;
-
- /* Potentially raise address to minimum location. */
- if (region.start < minimum)
- region.start = minimum;
-
/* Potentially raise address to meet alignment needs. */
region.start = ALIGN(region.start, CONFIG_PHYSICAL_ALIGN);
/* Did we raise the address above the passed in memory entry? */
- if (region.start > cur_entry.start + cur_entry.size)
+ if (region.start > region_end)
return;
/* Reduce size by any delta from the original address. */
- region.size -= region.start - start_orig;
-
- /* On 32-bit, reduce region size to fit within max size. */
- if (IS_ENABLED(CONFIG_X86_32) &&
- region.start + region.size > KERNEL_IMAGE_SIZE)
- region.size = KERNEL_IMAGE_SIZE - region.start;
+ region.size = region_end - region.start;
/* Return if region can't contain decompressed kernel */
if (region.size < image_size)
@@ -666,27 +635,19 @@ static void __process_mem_region(struct mem_vector *entry,
}
/* Store beginning of region if holds at least image_size. */
- if (overlap.start > region.start + image_size) {
- struct mem_vector beginning;
-
- beginning.start = region.start;
- beginning.size = overlap.start - region.start;
- process_gb_huge_pages(&beginning, image_size);
+ if (overlap.start >= region.start + image_size) {
+ region.size = overlap.start - region.start;
+ process_gb_huge_pages(&region, image_size);
}
- /* Return if overlap extends to or past end of region. */
- if (overlap.start + overlap.size >= region.start + region.size)
- return;
-
/* Clip off the overlapping region and start over. */
- region.size -= overlap.start - region.start + overlap.size;
region.start = overlap.start + overlap.size;
}
}
static bool process_mem_region(struct mem_vector *region,
- unsigned long long minimum,
- unsigned long long image_size)
+ unsigned long minimum,
+ unsigned long image_size)
{
int i;
/*
@@ -709,7 +670,7 @@ static bool process_mem_region(struct mem_vector *region,
* immovable memory and @region.
*/
for (i = 0; i < num_immovable_mem; i++) {
- unsigned long long start, end, entry_end, region_end;
+ u64 start, end, entry_end, region_end;
struct mem_vector entry;
if (!mem_overlaps(region, &immovable_mem[i]))
@@ -736,8 +697,8 @@ static bool process_mem_region(struct mem_vector *region,
#ifdef CONFIG_EFI
/*
- * Returns true if mirror region found (and must have been processed
- * for slots adding)
+ * Returns true if we processed the EFI memmap, which we prefer over the E820
+ * table if it is available.
*/
static bool
process_efi_entries(unsigned long minimum, unsigned long image_size)
@@ -839,20 +800,30 @@ static void process_e820_entries(unsigned long minimum,
static unsigned long find_random_phys_addr(unsigned long minimum,
unsigned long image_size)
{
+ u64 phys_addr;
+
+ /* Bail out early if it's impossible to succeed. */
+ if (minimum + image_size > mem_limit)
+ return 0;
+
/* Check if we had too many memmaps. */
if (memmap_too_large) {
debug_putstr("Aborted memory entries scan (more than 4 memmap= args)!\n");
return 0;
}
- /* Make sure minimum is aligned. */
- minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN);
+ if (!process_efi_entries(minimum, image_size))
+ process_e820_entries(minimum, image_size);
- if (process_efi_entries(minimum, image_size))
- return slots_fetch_random();
+ phys_addr = slots_fetch_random();
- process_e820_entries(minimum, image_size);
- return slots_fetch_random();
+ /* Perform a final check to make sure the address is in range. */
+ if (phys_addr < minimum || phys_addr + image_size > mem_limit) {
+ warn("Invalid physical address chosen!\n");
+ return 0;
+ }
+
+ return (unsigned long)phys_addr;
}
static unsigned long find_random_virt_addr(unsigned long minimum,
@@ -860,18 +831,12 @@ static unsigned long find_random_virt_addr(unsigned long minimum,
{
unsigned long slots, random_addr;
- /* Make sure minimum is aligned. */
- minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN);
- /* Align image_size for easy slot calculations. */
- image_size = ALIGN(image_size, CONFIG_PHYSICAL_ALIGN);
-
/*
* There are how many CONFIG_PHYSICAL_ALIGN-sized slots
* that can hold image_size within the range of minimum to
* KERNEL_IMAGE_SIZE?
*/
- slots = (KERNEL_IMAGE_SIZE - minimum - image_size) /
- CONFIG_PHYSICAL_ALIGN + 1;
+ slots = 1 + (KERNEL_IMAGE_SIZE - minimum - image_size) / CONFIG_PHYSICAL_ALIGN;
random_addr = kaslr_get_random_long("Virtual") % slots;
@@ -908,6 +873,11 @@ void choose_random_location(unsigned long input,
/* Prepare to add new identity pagetables on demand. */
initialize_identity_maps();
+ if (IS_ENABLED(CONFIG_X86_32))
+ mem_limit = KERNEL_IMAGE_SIZE;
+ else
+ mem_limit = MAXMEM;
+
/* Record the various known unsafe memory ranges. */
mem_avoid_init(input, input_size, *output);
@@ -917,6 +887,8 @@ void choose_random_location(unsigned long input,
* location:
*/
min_addr = min(*output, 512UL << 20);
+ /* Make sure minimum is aligned. */
+ min_addr = ALIGN(min_addr, CONFIG_PHYSICAL_ALIGN);
/* Walk available memory entries to find a random address. */
random_addr = find_random_phys_addr(min_addr, output_size);
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 726e264410ff..3efce27ba35c 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -70,8 +70,8 @@ int cmdline_find_option(const char *option, char *buffer, int bufsize);
int cmdline_find_option_bool(const char *option);
struct mem_vector {
- unsigned long long start;
- unsigned long long size;
+ u64 start;
+ u64 size;
};
#if CONFIG_RANDOMIZE_BASE
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-14 21:16:46 +0000