From bee6dc1a5d5986d8dfb29d6184a20fb5dd49e323 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anders=20F=20Bj=C3=B6rklund?= <anders.f.bjorklund@gmail.com>
Date: Mon, 30 Dec 2019 18:57:56 +0100
Subject: [PATCH] Add systemd patch for booting on AMD Ryzen

https://github.com/systemd/systemd/pull/12536

Backported to systemd version 240 for Ubuntu:
  [ Jeremy Soller ]
  * random-util: eat up bad RDRAND values seen on AMD CPUs.
    This fixes AMD Ryzen 3000 series failing to boot (LP: #1835809)
---
 .../240/rdrand-workaround-on-amd.patch        | 36 +++++++++++++++++++
 .../minikube-iso/configs/minikube_defconfig   |  1 +
 2 files changed, 37 insertions(+)
 create mode 100644 deploy/iso/minikube-iso/board/coreos/minikube/patches/systemd/240/rdrand-workaround-on-amd.patch

diff --git a/deploy/iso/minikube-iso/board/coreos/minikube/patches/systemd/240/rdrand-workaround-on-amd.patch b/deploy/iso/minikube-iso/board/coreos/minikube/patches/systemd/240/rdrand-workaround-on-amd.patch
new file mode 100644
index 000000000000..a209e58bfd78
--- /dev/null
+++ b/deploy/iso/minikube-iso/board/coreos/minikube/patches/systemd/240/rdrand-workaround-on-amd.patch
@@ -0,0 +1,36 @@
+Index: systemd-240/src/basic/random-util.c
+===================================================================
+--- systemd-240.orig/src/basic/random-util.c
++++ systemd-240/src/basic/random-util.c
+@@ -37,6 +37,7 @@ int rdrand(unsigned long *ret) {
+ 
+ #if defined(__i386__) || defined(__x86_64__)
+         static int have_rdrand = -1;
++        unsigned long v;
+         unsigned char err;
+ 
+         if (have_rdrand < 0) {
+@@ -56,9 +57,22 @@ int rdrand(unsigned long *ret) {
+ 
+         asm volatile("rdrand %0;"
+                      "setc %1"
+-                     : "=r" (*ret),
++                     : "=r" (v),
+                        "=qm" (err));
+ 
++       /* Apparently on some AMD CPUs RDRAND will sometimes (after a suspend/resume cycle?) report success
++        * via the carry flag but nonetheless return the same fixed value -1 in all cases. This appears to be
++        * a bad bug in the CPU or firmware. Let's deal with that and work-around this by explicitly checking
++        * for this special value (and also 0, just to be sure) and filtering it out. This is a work-around
++        * only however and something AMD really should fix properly. The Linux kernel should probably work
++        * around this issue by turning off RDRAND altogether on those CPUs. See:
++        * https://github.com/systemd/systemd/issues/11810 */
++       if (v == 0 || v == ULONG_MAX)
++               return log_debug_errno(SYNTHETIC_ERRNO(EUCLEAN),
++                                      "RDRAND returned suspicious value %lx, assuming bad hardware RNG, not using value.", v);
++
++       *ret = v;
++
+ #if HAS_FEATURE_MEMORY_SANITIZER
+         __msan_unpoison(&err, sizeof(err));
+ #endif
diff --git a/deploy/iso/minikube-iso/configs/minikube_defconfig b/deploy/iso/minikube-iso/configs/minikube_defconfig
index 6cdec2cf80d4..7d11f9a70539 100644
--- a/deploy/iso/minikube-iso/configs/minikube_defconfig
+++ b/deploy/iso/minikube-iso/configs/minikube_defconfig
@@ -17,6 +17,7 @@ BR2_SYSTEM_BIN_SH_BASH=y
 # BR2_TARGET_GENERIC_GETTY is not set
 BR2_ROOTFS_USERS_TABLES="$(BR2_EXTERNAL_MINIKUBE_PATH)/board/coreos/minikube/users"
 BR2_ROOTFS_OVERLAY="$(BR2_EXTERNAL_MINIKUBE_PATH)/board/coreos/minikube/rootfs-overlay"
+BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_MINIKUBE_PATH)/board/coreos/minikube/patches"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="$(BR2_EXTERNAL_MINIKUBE_PATH)/board/coreos/minikube/linux_defconfig"