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Diffstat (limited to 'arch/arm64/kernel/pi/kaslr_early.c')
-rw-r--r--arch/arm64/kernel/pi/kaslr_early.c78
1 files changed, 17 insertions, 61 deletions
diff --git a/arch/arm64/kernel/pi/kaslr_early.c b/arch/arm64/kernel/pi/kaslr_early.c
index 17bff6e399..0257b43819 100644
--- a/arch/arm64/kernel/pi/kaslr_early.c
+++ b/arch/arm64/kernel/pi/kaslr_early.c
@@ -14,69 +14,23 @@
#include <asm/archrandom.h>
#include <asm/memory.h>
+#include <asm/pgtable.h>
-/* taken from lib/string.c */
-static char *__strstr(const char *s1, const char *s2)
-{
- size_t l1, l2;
-
- l2 = strlen(s2);
- if (!l2)
- return (char *)s1;
- l1 = strlen(s1);
- while (l1 >= l2) {
- l1--;
- if (!memcmp(s1, s2, l2))
- return (char *)s1;
- s1++;
- }
- return NULL;
-}
-static bool cmdline_contains_nokaslr(const u8 *cmdline)
-{
- const u8 *str;
-
- str = __strstr(cmdline, "nokaslr");
- return str == cmdline || (str > cmdline && *(str - 1) == ' ');
-}
-
-static bool is_kaslr_disabled_cmdline(void *fdt)
-{
- if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {
- int node;
- const u8 *prop;
-
- node = fdt_path_offset(fdt, "/chosen");
- if (node < 0)
- goto out;
-
- prop = fdt_getprop(fdt, node, "bootargs", NULL);
- if (!prop)
- goto out;
-
- if (cmdline_contains_nokaslr(prop))
- return true;
+#include "pi.h"
- if (IS_ENABLED(CONFIG_CMDLINE_EXTEND))
- goto out;
+extern u16 memstart_offset_seed;
- return false;
- }
-out:
- return cmdline_contains_nokaslr(CONFIG_CMDLINE);
-}
-
-static u64 get_kaslr_seed(void *fdt)
+static u64 __init get_kaslr_seed(void *fdt, int node)
{
- int node, len;
+ static char const seed_str[] __initconst = "kaslr-seed";
fdt64_t *prop;
u64 ret;
+ int len;
- node = fdt_path_offset(fdt, "/chosen");
if (node < 0)
return 0;
- prop = fdt_getprop_w(fdt, node, "kaslr-seed", &len);
+ prop = fdt_getprop_w(fdt, node, seed_str, &len);
if (!prop || len != sizeof(u64))
return 0;
@@ -85,26 +39,28 @@ static u64 get_kaslr_seed(void *fdt)
return ret;
}
-asmlinkage u64 kaslr_early_init(void *fdt)
+u64 __init kaslr_early_init(void *fdt, int chosen)
{
- u64 seed;
+ u64 seed, range;
- if (is_kaslr_disabled_cmdline(fdt))
+ if (kaslr_disabled_cmdline())
return 0;
- seed = get_kaslr_seed(fdt);
+ seed = get_kaslr_seed(fdt, chosen);
if (!seed) {
if (!__early_cpu_has_rndr() ||
!__arm64_rndr((unsigned long *)&seed))
return 0;
}
+ memstart_offset_seed = seed & U16_MAX;
+
/*
* OK, so we are proceeding with KASLR enabled. Calculate a suitable
* kernel image offset from the seed. Let's place the kernel in the
- * middle half of the VMALLOC area (VA_BITS_MIN - 2), and stay clear of
- * the lower and upper quarters to avoid colliding with other
- * allocations.
+ * 'middle' half of the VMALLOC area, and stay clear of the lower and
+ * upper quarters to avoid colliding with other allocations.
*/
- return BIT(VA_BITS_MIN - 3) + (seed & GENMASK(VA_BITS_MIN - 3, 0));
+ range = (VMALLOC_END - KIMAGE_VADDR) / 2;
+ return range / 2 + (((__uint128_t)range * seed) >> 64);
}