Kernel: Add a more expressive API for getting random bytes

We now have these API's in <Kernel/Random.h>:

    - get_fast_random_bytes(u8* buffer, size_t buffer_size)
    - get_good_random_bytes(u8* buffer, size_t buffer_size)
    - get_fast_random<T>()
    - get_good_random<T>()

Internally they both use x86 RDRAND if available, otherwise they fall
back to the same LCG we had in RandomDevice all along.

The main purpose of this patch is to give kernel code a way to better
express its needs for random data.

Randomness is something that will require a lot more work, but this is
hopefully a step in the right direction.

1 files changed, 6 insertions, 0 deletions

diff --git a/Kernel/init.cpp b/Kernel/init.cpp
index 24f1fd0ea8..b01d496abe 100644
--- a/Kernel/init.cpp
+++ b/Kernel/init.cpp
@@ -307,6 +307,12 @@ extern "C" [[noreturn]] void init(u32 physical_address_for_kernel_page_tables)
         kprintf("x86: RDTSC support restricted\n");
     }
 
+    if (g_cpu_supports_rdrand) {
+        kprintf("x86: Using RDRAND for good randomness\n");
+    } else {
+        kprintf("x86: No RDRAND support detected. Randomness will be shitty\n");
+    }
+
     RTC::initialize();
     PIC::initialize();
     gdt_init();