From bcfcbb6bae649c870037cc8c4e2685b2a8927c3d Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 11 Aug 2014 12:20:58 +0200
Subject: s390: add system information as device randomness

The virtual-machine cpu information data block and the cpu-id of
the boot cpu can be used as source of device randomness.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/kernel/setup.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

(limited to 'arch/s390/kernel/setup.c')

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index ae1d5be..82bc113 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -24,6 +24,7 @@
 #include <linux/stddef.h>
 #include <linux/unistd.h>
 #include <linux/ptrace.h>
+#include <linux/random.h>
 #include <linux/user.h>
 #include <linux/tty.h>
 #include <linux/ioport.h>
@@ -61,6 +62,7 @@
 #include <asm/diag.h>
 #include <asm/os_info.h>
 #include <asm/sclp.h>
+#include <asm/sysinfo.h>
 #include "entry.h"
 
 /*
@@ -766,6 +768,7 @@ static void __init setup_hwcaps(void)
 #endif
 
 	get_cpu_id(&cpu_id);
+	add_device_randomness(&cpu_id, sizeof(cpu_id));
 	switch (cpu_id.machine) {
 	case 0x9672:
 #if !defined(CONFIG_64BIT)
@@ -804,6 +807,19 @@ static void __init setup_hwcaps(void)
 }
 
 /*
+ * Add system information as device randomness
+ */
+static void __init setup_randomness(void)
+{
+	struct sysinfo_3_2_2 *vmms;
+
+	vmms = (struct sysinfo_3_2_2 *) alloc_page(GFP_KERNEL);
+	if (vmms && stsi(vmms, 3, 2, 2) == 0 && vmms->count)
+		add_device_randomness(&vmms, vmms->count);
+	free_page((unsigned long) vmms);
+}
+
+/*
  * Setup function called from init/main.c just after the banner
  * was printed.
  */
@@ -901,6 +917,9 @@ void __init setup_arch(char **cmdline_p)
 
 	/* Setup zfcpdump support */
 	setup_zfcpdump();
+
+	/* Add system specific data to the random pool */
+	setup_randomness();
 }
 
 #ifdef CONFIG_32BIT
-- 
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