diff mbox

[2/2] ARM: kexec: Check segment memory addresses

Message ID 1347007260-13271-3-git-send-email-matthew.leach@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Matthew Leach Sept. 7, 2012, 8:41 a.m. UTC 
Ensure that the memory regions that are set within the segments
correspond to physical contiguous memory regions.

Reviewed-by: Simon Horman <horms@verge.net.au>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
---
 arch/arm/kernel/machine_kexec.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Russell King - ARM Linux Sept. 7, 2012, 8:49 a.m. UTC | #1 
On Fri, Sep 07, 2012 at 09:41:00AM +0100, Matthew Leach wrote:
> Ensure that the memory regions that are set within the segments
> correspond to physical contiguous memory regions.
> 
> Reviewed-by: Simon Horman <horms@verge.net.au>
> Reviewed-by: Will Deacon <will.deacon@arm.com>
> Signed-off-by: Matthew Leach <matthew.leach@arm.com>

What about platforms which pull out bits of physical RAM from memblock
via arm_memblock_steal() ?  Doesn't this mean such platforms will reduce
their available memory on each subsequent kexec?
Will Deacon Sept. 7, 2012, 10:04 a.m. UTC | #2 
On Fri, Sep 07, 2012 at 09:49:38AM +0100, Russell King - ARM Linux wrote:
> On Fri, Sep 07, 2012 at 09:41:00AM +0100, Matthew Leach wrote:
> > Ensure that the memory regions that are set within the segments
> > correspond to physical contiguous memory regions.
> > 
> > Reviewed-by: Simon Horman <horms@verge.net.au>
> > Reviewed-by: Will Deacon <will.deacon@arm.com>
> > Signed-off-by: Matthew Leach <matthew.leach@arm.com>
> 
> What about platforms which pull out bits of physical RAM from memblock
> via arm_memblock_steal() ?  Doesn't this mean such platforms will reduce
> their available memory on each subsequent kexec?

I don't think that will happen. All that kexec does is check that the
location where it wants to load the new kernel is physically contiguous -- the
memblock configuration is not inherited by the target kernel.

What *might* happen is that a memblock_steal on the host kernel could cause
the kexec to fail with -EINVAL if the area removed corresponds to the area
where the target kernel wants to be loaded. I think this is correct
behaviour, because we have no idea what the stolen region is being used for.

Will
diff mbox

Patch

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index a6bbc0f..524139a 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -8,6 +8,7 @@ 
 #include <linux/reboot.h>
 #include <linux/io.h>
 #include <linux/irq.h>
+#include <linux/memblock.h>
 #include <asm/pgtable.h>
 #include <linux/of_fdt.h>
 #include <asm/pgalloc.h>
@@ -42,6 +43,12 @@  int machine_kexec_prepare(struct kimage *image)
 	for (i = 0; i < image->nr_segments; i++) {
 		current_segment = &image->segment[i];
 
+		err = memblock_is_region_memory(current_segment->mem,
+						current_segment->memsz);
+		if (err)
+			return - EINVAL;
+
+
 		err = get_user(header, (__be32*)current_segment->buf);
 		if (err)
 			return err;