Merge tag 'drm-next-2018-08-24' of git://anongit.freedesktop.org/drm/drm

[linux-2.6-microblaze.git] / lib / vsprintf.c

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index cda1862..d5b3a3f 100644 (file)
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1651,6 +1651,17 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
        return widen_string(buf, buf - buf_start, end, spec);
 }
 
+/* Make pointers available for printing early in the boot sequence. */
+static int debug_boot_weak_hash __ro_after_init;
+
+static int __init debug_boot_weak_hash_enable(char *str)
+{
+       debug_boot_weak_hash = 1;
+       pr_info("debug_boot_weak_hash enabled\n");
+       return 0;
+}
+early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
+
 static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
 static siphash_key_t ptr_key __read_mostly;
 
@@ -1675,8 +1686,16 @@ static struct random_ready_callback random_ready = {
 
 static int __init initialize_ptr_random(void)
 {
-       int ret = add_random_ready_callback(&random_ready);
+       int key_size = sizeof(ptr_key);
+       int ret;
 
+       /* Use hw RNG if available. */
+       if (get_random_bytes_arch(&ptr_key, key_size) == key_size) {
+               static_branch_disable(&not_filled_random_ptr_key);
+               return 0;
+       }
+
+       ret = add_random_ready_callback(&random_ready);
        if (!ret) {
                return 0;
        } else if (ret == -EALREADY) {
@@ -1695,6 +1714,12 @@ static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
        const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
        unsigned long hashval;
 
+       /* When debugging early boot use non-cryptographically secure hash. */
+       if (unlikely(debug_boot_weak_hash)) {
+               hashval = hash_long((unsigned long)ptr, 32);
+               return pointer_string(buf, end, (const void *)hashval, spec);
+       }
+
        if (static_branch_unlikely(&not_filled_random_ptr_key)) {
                spec.field_width = 2 * sizeof(ptr);
                /* string length must be less than default_width */