Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:
 "The main changes:

   - add initial commits to randomize kernel memory section virtual
     addresses, enabled via a new kernel option: RANDOMIZE_MEMORY
     (Thomas Garnier, Kees Cook, Baoquan He, Yinghai Lu)

   - enhance KASLR (RANDOMIZE_BASE) physical memory randomization (Kees
     Cook)

   - EBDA/BIOS region boot quirk cleanups (Andy Lutomirski, Ingo Molnar)

   - misc cleanups/fixes"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Simplify EBDA-vs-BIOS reservation logic
  x86/boot: Clarify what x86_legacy_features.reserve_bios_regions does
  x86/boot: Reorganize and clean up the BIOS area reservation code
  x86/mm: Do not reference phys addr beyond kernel
  x86/mm: Add memory hotplug support for KASLR memory randomization
  x86/mm: Enable KASLR for vmalloc memory regions
  x86/mm: Enable KASLR for physical mapping memory regions
  x86/mm: Implement ASLR for kernel memory regions
  x86/mm: Separate variable for trampoline PGD
  x86/mm: Add PUD VA support for physical mapping
  x86/mm: Update physical mapping variable names
  x86/mm: Refactor KASLR entropy functions
  x86/KASLR: Fix boot crash with certain memory configurations
  x86/boot/64: Add forgotten end of function marker
  x86/KASLR: Allow randomization below the load address
  x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G
  x86/KASLR: Randomize virtual address separately
  x86/KASLR: Clarify identity map interface
  x86/boot: Refuse to build with data relocations
  x86/KASLR, x86/power: Remove x86 hibernation restrictions

2 files changed, 91 insertions, 0 deletions

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index ec969cc3eb20..34a74131a12c 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -24,6 +24,7 @@ lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
 lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
+lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
 
 obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
 
diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c
new file mode 100644
index 000000000000..f7dfeda83e5c
--- /dev/null
+++ b/arch/x86/lib/kaslr.c
@@ -0,0 +1,90 @@
+/*
+ * Entropy functions used on early boot for KASLR base and memory
+ * randomization. The base randomization is done in the compressed
+ * kernel and memory randomization is done early when the regular
+ * kernel starts. This file is included in the compressed kernel and
+ * normally linked in the regular.
+ */
+#include <asm/kaslr.h>
+#include <asm/msr.h>
+#include <asm/archrandom.h>
+#include <asm/e820.h>
+#include <asm/io.h>
+
+/*
+ * When built for the regular kernel, several functions need to be stubbed out
+ * or changed to their regular kernel equivalent.
+ */
+#ifndef KASLR_COMPRESSED_BOOT
+#include <asm/cpufeature.h>
+#include <asm/setup.h>
+
+#define debug_putstr(v) early_printk(v)
+#define has_cpuflag(f) boot_cpu_has(f)
+#define get_boot_seed() kaslr_offset()
+#endif
+
+#define I8254_PORT_CONTROL      0x43
+#define I8254_PORT_COUNTER0     0x40
+#define I8254_CMD_READBACK      0xC0
+#define I8254_SELECT_COUNTER0   0x02
+#define I8254_STATUS_NOTREADY   0x40
+static inline u16 i8254(void)
+{
+        u16 status, timer;
+
+        do {
+                outb(I8254_PORT_CONTROL,
+                     I8254_CMD_READBACK | I8254_SELECT_COUNTER0);
+                status = inb(I8254_PORT_COUNTER0);
+                timer  = inb(I8254_PORT_COUNTER0);
+                timer |= inb(I8254_PORT_COUNTER0) << 8;
+        } while (status & I8254_STATUS_NOTREADY);
+
+        return timer;
+}
+
+unsigned long kaslr_get_random_long(const char *purpose)
+{
+#ifdef CONFIG_X86_64
+        const unsigned long mix_const = 0x5d6008cbf3848dd3UL;
+#else
+        const unsigned long mix_const = 0x3f39e593UL;
+#endif
+        unsigned long raw, random = get_boot_seed();
+        bool use_i8254 = true;
+
+        debug_putstr(purpose);
+        debug_putstr(" KASLR using");
+
+        if (has_cpuflag(X86_FEATURE_RDRAND)) {
+                debug_putstr(" RDRAND");
+                if (rdrand_long(&raw)) {
+                        random ^= raw;
+                        use_i8254 = false;
+                }
+        }
+
+        if (has_cpuflag(X86_FEATURE_TSC)) {
+                debug_putstr(" RDTSC");
+                raw = rdtsc();
+
+                random ^= raw;
+                use_i8254 = false;
+        }
+
+        if (use_i8254) {
+                debug_putstr(" i8254");
+                random ^= i8254();
+        }
+
+        /* Circular multiply for better bit diffusion */
+        asm("mul %3"
+            : "=a" (random), "=d" (raw)
+            : "a" (random), "rm" (mix_const));
+        random += raw;
+
+        debug_putstr("...\n");
+
+        return random;
+}