ARM: kdump: advertise boot aliased crash kernel resource

Advertise a resource which describes where the crash kernel is located
in the boot view of RAM.  This allows kexec-tools to have this vital
information.

Link: http://lkml.kernel.org/r/E1b8knz-0004H4-Bd@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Baoquan He <bhe@redhat.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index da2f6c360f6b..6c8c888c1152 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -1000,9 +1000,25 @@ static void __init reserve_crashkernel(void)
                 (unsigned long)(crash_base >> 20),
                 (unsigned long)(total_mem >> 20));
 
+        /* The crashk resource must always be located in normal mem */
         crashk_res.start = crash_base;
         crashk_res.end = crash_base + crash_size - 1;
         insert_resource(&iomem_resource, &crashk_res);
+
+        if (arm_has_idmap_alias()) {
+                /*
+                 * If we have a special RAM alias for use at boot, we
+                 * need to advertise to kexec tools where the alias is.
+                 */
+                static struct resource crashk_boot_res = {
+                        .name = "Crash kernel (boot alias)",
+                        .flags = IORESOURCE_BUSY | IORESOURCE_MEM,
+                };
+
+                crashk_boot_res.start = phys_to_idmap(crash_base);
+                crashk_boot_res.end = crashk_boot_res.start + crash_size - 1;
+                insert_resource(&iomem_resource, &crashk_boot_res);
+        }
 }
 #else
 static inline void reserve_crashkernel(void) {}