[RFC v1 1/4] x86, boot: Refactor KASLR entropy functions

[Thomas Garnier]

Move the KASLR entropy functions in x86/libray to be used in early
kernel boot for KASLR memory randomization.

Signed-off-by: Thomas Garnier 
---
Based on next-20160413
---
 arch/x86/boot/compressed/aslr.c | 76 +++
 arch/x86/include/asm/kaslr.h|  6 
 arch/x86/lib/Makefile   |  1 +
 arch/x86/lib/kaslr.c| 79 +
 4 files changed, 91 insertions(+), 71 deletions(-)
 create mode 100644 arch/x86/include/asm/kaslr.h
 create mode 100644 arch/x86/lib/kaslr.c

diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index 6a9b96b..6584c0e 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -1,9 +1,5 @@
 #include "misc.h"
 
-#include 
-#include 
-#include 
-
 #include 
 #include 
 #include 
@@ -14,26 +10,6 @@
 static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@"
LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION;
 
-#define I8254_PORT_CONTROL 0x43
-#define I8254_PORT_COUNTER00x40
-#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;
-}
-
 static unsigned long rotate_xor(unsigned long hash, const void *area,
size_t size)
 {
@@ -50,7 +26,7 @@ static unsigned long rotate_xor(unsigned long hash, const 
void *area,
 }
 
 /* Attempt to create a simple but unpredictable starting entropy. */
-static unsigned long get_random_boot(void)
+static unsigned long get_boot_seed(void)
 {
unsigned long hash = 0;
 
@@ -60,50 +36,6 @@ static unsigned long get_random_boot(void)
return hash;
 }
 
-static unsigned long get_random_long(void)
-{
-#ifdef CONFIG_X86_64
-   const unsigned long mix_const = 0x5d6008cbf3848dd3UL;
-#else
-   const unsigned long mix_const = 0x3f39e593UL;
-#endif
-   unsigned long raw, random = get_random_boot();
-   bool use_i8254 = true;
-
-   debug_putstr("KASLR using");
-
-   if (has_cpuflag(X86_FEATURE_RDRAND)) {
-   debug_putstr(" RDRAND");
-   if (rdrand_long()) {
-   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;
-}
-
 struct mem_vector {
unsigned long start;
unsigned long size;
@@ -111,7 +43,6 @@ struct mem_vector {
 
 #define MEM_AVOID_MAX 5
 static struct mem_vector mem_avoid[MEM_AVOID_MAX];
-
 static bool mem_contains(struct mem_vector *region, struct mem_vector *item)
 {
/* Item at least partially before region. */
@@ -220,13 +151,16 @@ static void slots_append(unsigned long addr)
slots[slot_max++] = addr;
 }
 
+#define KASLR_COMPRESSED_BOOT
+#include "../../lib/kaslr.c"
+
 static unsigned long slots_fetch_random(void)
 {
/* Handle case of no slots stored. */
if (slot_max == 0)
return 0;
 
-   return slots[get_random_long() % slot_max];
+   return slots[kaslr_get_random_boot_long() % slot_max];
 }
 
 static void process_e820_entry(struct e820entry *entry,
diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
new file mode 100644
index 000..2ae1429
--- /dev/null
+++ b/arch/x86/include/asm/kaslr.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_KASLR_H_
+#define _ASM_KASLR_H_
+
+unsigned long kaslr_get_random_boot_long(void);
+
+#endif
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 72a5767..cfa6d07 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
 
diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c
new file mode 100644
index 000..ffb22ba
--- /dev/null
+++ b/arch/x86/lib/kaslr.c
@@ -0,0 +1,79 @@
+#include 
+#include 

[RFC v1 1/4] x86, boot: Refactor KASLR entropy functions

[Thomas Garnier]

Move the KASLR entropy functions in x86/libray to be used in early
kernel boot for KASLR memory randomization.

Signed-off-by: Thomas Garnier 
---
Based on next-20160413
---
 arch/x86/boot/compressed/aslr.c | 76 +++
 arch/x86/include/asm/kaslr.h|  6 
 arch/x86/lib/Makefile   |  1 +
 arch/x86/lib/kaslr.c| 79 +
 4 files changed, 91 insertions(+), 71 deletions(-)
 create mode 100644 arch/x86/include/asm/kaslr.h
 create mode 100644 arch/x86/lib/kaslr.c

diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index 6a9b96b..6584c0e 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -1,9 +1,5 @@
 #include "misc.h"
 
-#include 
-#include 
-#include 
-
 #include 
 #include 
 #include 
@@ -14,26 +10,6 @@
 static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@"
LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION;
 
-#define I8254_PORT_CONTROL 0x43
-#define I8254_PORT_COUNTER00x40
-#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;
-}
-
 static unsigned long rotate_xor(unsigned long hash, const void *area,
size_t size)
 {
@@ -50,7 +26,7 @@ static unsigned long rotate_xor(unsigned long hash, const 
void *area,
 }
 
 /* Attempt to create a simple but unpredictable starting entropy. */
-static unsigned long get_random_boot(void)
+static unsigned long get_boot_seed(void)
 {
unsigned long hash = 0;
 
@@ -60,50 +36,6 @@ static unsigned long get_random_boot(void)
return hash;
 }
 
-static unsigned long get_random_long(void)
-{
-#ifdef CONFIG_X86_64
-   const unsigned long mix_const = 0x5d6008cbf3848dd3UL;
-#else
-   const unsigned long mix_const = 0x3f39e593UL;
-#endif
-   unsigned long raw, random = get_random_boot();
-   bool use_i8254 = true;
-
-   debug_putstr("KASLR using");
-
-   if (has_cpuflag(X86_FEATURE_RDRAND)) {
-   debug_putstr(" RDRAND");
-   if (rdrand_long()) {
-   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;
-}
-
 struct mem_vector {
unsigned long start;
unsigned long size;
@@ -111,7 +43,6 @@ struct mem_vector {
 
 #define MEM_AVOID_MAX 5
 static struct mem_vector mem_avoid[MEM_AVOID_MAX];
-
 static bool mem_contains(struct mem_vector *region, struct mem_vector *item)
 {
/* Item at least partially before region. */
@@ -220,13 +151,16 @@ static void slots_append(unsigned long addr)
slots[slot_max++] = addr;
 }
 
+#define KASLR_COMPRESSED_BOOT
+#include "../../lib/kaslr.c"
+
 static unsigned long slots_fetch_random(void)
 {
/* Handle case of no slots stored. */
if (slot_max == 0)
return 0;
 
-   return slots[get_random_long() % slot_max];
+   return slots[kaslr_get_random_boot_long() % slot_max];
 }
 
 static void process_e820_entry(struct e820entry *entry,
diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
new file mode 100644
index 000..2ae1429
--- /dev/null
+++ b/arch/x86/include/asm/kaslr.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_KASLR_H_
+#define _ASM_KASLR_H_
+
+unsigned long kaslr_get_random_boot_long(void);
+
+#endif
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 72a5767..cfa6d07 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
 
diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c
new file mode 100644
index 000..ffb22ba
--- /dev/null
+++ b/arch/x86/lib/kaslr.c
@@ -0,0 +1,79 @@
+#include 
+#include 
+#include 
+#include