Patchwork of: Feed entire flattened device tree into the random pool

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Submitter Anton Blanchard
Date July 25, 2013, 4:30 a.m.
Message ID <20130725143031.16af0a96@kryten>
Download mbox | patch
Permalink /patch/261582/
State Superseded
Headers show

Comments

Anton Blanchard - July 25, 2013, 4:30 a.m.
Hi Michael,

> But why not put the initcall in drivers/of/fdt.c, that way it's not
> early but it's still common ?

Good idea! How does this look? So long as it happens before
module_init(rand_initialize) we should be good.

Anton
--

We feed the entire DMI table into the random pool to provide
better random data during early boot, so do the same with the
flattened device tree.

Signed-off-by: Anton Blanchard <anton@samba.org>
---

v2: move to drivers/of/fdt.c as suggested by Michael Ellerman
David Gibson - July 25, 2013, 4:42 a.m.
On Thu, Jul 25, 2013 at 02:30:31PM +1000, Anton Blanchard wrote:
> 
> Hi Michael,
> 
> > But why not put the initcall in drivers/of/fdt.c, that way it's not
> > early but it's still common ?
> 
> Good idea! How does this look? So long as it happens before
> module_init(rand_initialize) we should be good.

This must be some strange new meaning of the word "random" of which I
was not previously aware.  But I guess it's marginally better than
nothing.
Grant Likely - July 28, 2013, 4:49 a.m.
On Thu, 25 Jul 2013 14:30:31 +1000, Anton Blanchard <anton@samba.org> wrote:
> 
> Hi Michael,
> 
> > But why not put the initcall in drivers/of/fdt.c, that way it's not
> > early but it's still common ?
> 
> Good idea! How does this look? So long as it happens before
> module_init(rand_initialize) we should be good.
> 
> Anton
> --
> 
> We feed the entire DMI table into the random pool to provide
> better random data during early boot, so do the same with the
> flattened device tree.
> 
> Signed-off-by: Anton Blanchard <anton@samba.org>
> ---
> 
> v2: move to drivers/of/fdt.c as suggested by Michael Ellerman
> 
> Index: b/drivers/of/fdt.c
> ===================================================================
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -17,6 +17,7 @@
>  #include <linux/string.h>
>  #include <linux/errno.h>
>  #include <linux/slab.h>
> +#include <linux/random.h>
>  
>  #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
>  #ifdef CONFIG_PPC
> @@ -714,3 +715,14 @@ void __init unflatten_device_tree(void)
>  }
>  
>  #endif /* CONFIG_OF_EARLY_FLATTREE */
> +
> +/* Feed entire flattened device tree into the random pool */
> +static int __init add_fdt_randomness(void)
> +{
> +	if (initial_boot_params)
> +		add_device_randomness(initial_boot_params,
> +				      initial_boot_params->totalsize);

be32_to_cpu(initial_boot_params->totalsize);

g.

Patch

Index: b/drivers/of/fdt.c
===================================================================
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -17,6 +17,7 @@ 
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
+#include <linux/random.h>
 
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #ifdef CONFIG_PPC
@@ -714,3 +715,14 @@  void __init unflatten_device_tree(void)
 }
 
 #endif /* CONFIG_OF_EARLY_FLATTREE */
+
+/* Feed entire flattened device tree into the random pool */
+static int __init add_fdt_randomness(void)
+{
+	if (initial_boot_params)
+		add_device_randomness(initial_boot_params,
+				      initial_boot_params->totalsize);
+
+	return 0;
+}
+core_initcall(add_fdt_randomness);