Merge GH #2026 Add support for POWER9 hardware RNG

10 files changed, 124 insertions, 1 deletions

diff --git a/src/build-data/arch/ppc64.txt b/src/build-data/arch/ppc64.txt
index 23d3bb2a1..470bee2db 100644
--- a/src/build-data/arch/ppc64.txt
+++ b/src/build-data/arch/ppc64.txt
@@ -13,4 +13,5 @@ ppc64el
 <isa_extensions>
 altivec
 ppccrypto
+power9
 </isa_extensions>
diff --git a/src/build-data/buildh.in b/src/build-data/buildh.in
index caa160eb0..425d06498 100644
--- a/src/build-data/buildh.in
+++ b/src/build-data/buildh.in
@@ -181,7 +181,7 @@
 * broken system RNG.
 */
 #define BOTAN_ENTROPY_DEFAULT_SOURCES \
-   { "rdseed", "rdrand", "getentropy", "dev_random", \
+   { "rdseed", "rdrand", "p9_darn", "getentropy", "dev_random", \
      "system_rng", "proc_walk", "system_stats" }
 
 /* Multiplier on a block cipher's native parallelism */
diff --git a/src/build-data/cc/gcc.txt b/src/build-data/cc/gcc.txt
index f495af4e6..cc3ce99e1 100644
--- a/src/build-data/cc/gcc.txt
+++ b/src/build-data/cc/gcc.txt
@@ -63,6 +63,7 @@ sha     -> "-msha"
 altivec -> "-maltivec"
 
 ppccrypto -> "-mcrypto"
+power9    -> "-mcpu=power9"
 
 arm64:armv8crypto -> ""
 arm64:armv8sm3 -> "-march=armv8.2-a+sm4"
diff --git a/src/lib/entropy/entropy_srcs.cpp b/src/lib/entropy/entropy_srcs.cpp
index 85e0b6dc5..ba60ed62d 100644
--- a/src/lib/entropy/entropy_srcs.cpp
+++ b/src/lib/entropy/entropy_srcs.cpp
@@ -20,6 +20,10 @@
   #include <botan/internal/rdseed.h>
 #endif
 
+#if defined(BOTAN_HAS_ENTROPY_SRC_DARN)
+  #include <botan/internal/p9_darn.h>
+#endif
+
 #if defined(BOTAN_HAS_ENTROPY_SRC_DEV_RANDOM)
   #include <botan/internal/dev_random.h>
 #endif
@@ -83,6 +87,13 @@ std::unique_ptr<Entropy_Source> Entropy_Source::create(const std::string& name)
       }
 #endif
 
+#if defined(BOTAN_HAS_ENTROPY_SRC_DARN)
+   if(name == "p9_darn")
+      {
+      return std::unique_ptr<Entropy_Source>(new POWER9_DARN);
+      }
+#endif
+
 #if defined(BOTAN_HAS_ENTROPY_SRC_GETENTROPY)
    if(name == "getentropy")
       {
diff --git a/src/lib/entropy/p9_darn/info.txt b/src/lib/entropy/p9_darn/info.txt
new file mode 100644
index 000000000..47d99aa3d
--- /dev/null
+++ b/src/lib/entropy/p9_darn/info.txt
@@ -0,0 +1,11 @@
+<defines>
+ENTROPY_SRC_DARN -> 20180610
+</defines>
+
+<header:internal>
+p9_darn.h
+</header:internal>
+
+<arch>
+ppc64
+</arch>
diff --git a/src/lib/entropy/p9_darn/p9_darn.cpp b/src/lib/entropy/p9_darn/p9_darn.cpp
new file mode 100644
index 000000000..8731b94e1
--- /dev/null
+++ b/src/lib/entropy/p9_darn/p9_darn.cpp
@@ -0,0 +1,65 @@
+/*
+* (C) 2019 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/p9_darn.h>
+#include <botan/cpuid.h>
+
+namespace Botan {
+
+namespace {
+
+bool read_darn(secure_vector<uint64_t>& seed)
+   {
+   const size_t DARN_RETRIES = 512;
+
+   for(size_t i = 0; i != DARN_RETRIES; ++i)
+      {
+      uint64_t r = 0;
+
+      // DARN 0: 32-bit conditioned, 1: 64-bit condition, 2: 64-bit raw (ala RDSEED)
+      asm volatile("darn %0, 2" : "=r" (r));
+
+      // DARN indicates error by 0xFF..FF, ie is biased (!?!?)
+      if((~r) != 0)
+         {
+         seed.push_back(r);
+         return true;
+         }
+      }
+
+   return false; // failed to produce an output after many attempts
+   }
+
+}
+
+size_t POWER9_DARN::poll(RandomNumberGenerator& rng)
+   {
+   const size_t DARN_BYTES = 1024;
+   static_assert(DARN_BYTES % 8 == 0, "Bad DARN configuration");
+
+   if(CPUID::has_darn_rng())
+      {
+      secure_vector<uint64_t> seed;
+      seed.reserve(DARN_BYTES / 8);
+
+      for(size_t p = 0; p != DARN_BYTES / 8; ++p)
+         {
+         if(!read_darn(seed))
+            break;
+         }
+
+      if(seed.size() > 0)
+         {
+         rng.add_entropy(reinterpret_cast<const uint8_t*>(seed.data()),
+                         seed.size() * sizeof(uint32_t));
+         }
+      }
+
+   // DARN is used but not trusted
+   return 0;
+   }
+
+}
diff --git a/src/lib/entropy/p9_darn/p9_darn.h b/src/lib/entropy/p9_darn/p9_darn.h
new file mode 100644
index 000000000..9d8c508a1
--- /dev/null
+++ b/src/lib/entropy/p9_darn/p9_darn.h
@@ -0,0 +1,23 @@
+/*
+* (C) 2019 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_ENTROPY_SRC_DARN_H_
+#define BOTAN_ENTROPY_SRC_DARN_H_
+
+#include <botan/entropy_src.h>
+
+namespace Botan {
+
+class POWER9_DARN final : public Entropy_Source
+   {
+   public:
+      std::string name() const override { return "p9_darn"; }
+      size_t poll(RandomNumberGenerator& rng) override;
+   };
+
+}
+
+#endif
diff --git a/src/lib/utils/cpuid/cpuid.cpp b/src/lib/utils/cpuid/cpuid.cpp
index e890af061..18ccff419 100644
--- a/src/lib/utils/cpuid/cpuid.cpp
+++ b/src/lib/utils/cpuid/cpuid.cpp
@@ -63,6 +63,7 @@ std::string CPUID::to_string()
 #if defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
    CPUID_PRINT(altivec);
    CPUID_PRINT(ppc_crypto);
+   CPUID_PRINT(darn_rng);
 #endif
 
 #if defined(BOTAN_TARGET_CPU_IS_ARM_FAMILY)
diff --git a/src/lib/utils/cpuid/cpuid.h b/src/lib/utils/cpuid/cpuid.h
index d278a8fcc..256c6cc57 100644
--- a/src/lib/utils/cpuid/cpuid.h
+++ b/src/lib/utils/cpuid/cpuid.h
@@ -107,6 +107,7 @@ class BOTAN_PUBLIC_API(2,1) CPUID final
 #if defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
          CPUID_ALTIVEC_BIT    = (1ULL << 0),
          CPUID_PPC_CRYPTO_BIT = (1ULL << 1),
+         CPUID_DARN_BIT       = (1ULL << 2),
 #endif
 
 #if defined(BOTAN_TARGET_CPU_IS_ARM_FAMILY)
@@ -138,6 +139,12 @@ class BOTAN_PUBLIC_API(2,1) CPUID final
       static bool has_ppc_crypto()
          { return has_cpuid_bit(CPUID_PPC_CRYPTO_BIT); }
 
+      /**
+      * Check if the processor supports POWER9 DARN RNG
+      */
+      static bool has_darn_rng()
+         { return has_cpuid_bit(CPUID_DARN_BIT); }
+
 #endif
 
 #if defined(BOTAN_TARGET_CPU_IS_ARM_FAMILY)
diff --git a/src/lib/utils/cpuid/cpuid_ppc.cpp b/src/lib/utils/cpuid/cpuid_ppc.cpp
index 08a04cafd..ff528d88e 100644
--- a/src/lib/utils/cpuid/cpuid_ppc.cpp
+++ b/src/lib/utils/cpuid/cpuid_ppc.cpp
@@ -58,6 +58,7 @@ uint64_t CPUID::CPUID_Data::detect_cpu_features(size_t* cache_line_size)
    enum PPC_hwcap_bit {
       ALTIVEC_bit  = (1 << 28),
       CRYPTO_bit   = (1 << 25),
+      DARN_bit     = (1 << 21),
 
       ARCH_hwcap_altivec = 16, // AT_HWCAP
       ARCH_hwcap_crypto  = 26, // AT_HWCAP2
@@ -72,6 +73,8 @@ uint64_t CPUID::CPUID_Data::detect_cpu_features(size_t* cache_line_size)
    const unsigned long hwcap_crypto = OS::get_auxval(PPC_hwcap_bit::ARCH_hwcap_crypto);
    if(hwcap_crypto & PPC_hwcap_bit::CRYPTO_bit)
      detected_features |= CPUID::CPUID_PPC_CRYPTO_BIT;
+   if(hwcap_crypto & PPC_hwcap_bit::DARN_bit)
+     detected_features |= CPUID::CPUID_DARN_BIT;
 
    return detected_features;