[RFC PATCH 1/1] PPC64: Release memory before exiting

[Ram Pai]

Grub fails to load on ppc64 architecture with the following message..

"Trying to load:  from: /vdevice/address@hidden/address@hidden
...
Claim: e50ea00 700000 e619b18 0 -1 4000 200000 23a88 200000 23a88 0
Memory for ELF file is already in use! "

This is caused if a earlier instance of grub exited without releasing
memory. This problem is seen when grub is booted from some device;
either disk or cdrom or network, and then exited followed by boot from
another device.

The following patch releases memory allocated to grub by
SLOF/Openfirmware before exiting.

Signed-off-by: Ram Pai <address@hidden>
---
 grub-core/kern/ieee1275/init.c   |  1 +
 grub-core/kern/ieee1275/openfw.c | 29 +++++++++++++++++++++++++++++
 include/grub/ieee1275/ieee1275.h |  7 +++++++
 3 files changed, 37 insertions(+)

diff --git a/grub-core/kern/ieee1275/init.c b/grub-core/kern/ieee1275/init.c
index d5bd74d..5f9f170 100644
--- a/grub-core/kern/ieee1275/init.c
+++ b/grub-core/kern/ieee1275/init.c
@@ -62,6 +62,7 @@ grub_addr_t grub_ieee1275_original_stack;
 void
 grub_exit (void)
 {
+  grub_releasemap();
   grub_ieee1275_exit ();
 }
 
diff --git a/grub-core/kern/ieee1275/openfw.c b/grub-core/kern/ieee1275/openfw.c
index ced8e3f..339fa45 100644
--- a/grub-core/kern/ieee1275/openfw.c
+++ b/grub-core/kern/ieee1275/openfw.c
@@ -302,6 +302,34 @@ grub_ieee1275_map (grub_addr_t phys, grub_addr_t virt, 
grub_size_t size,
   return IEEE1275_VALUE(args.catch_result);
 }
 
+/* Preallocate IEEE1275_MAX_MAP_RESOURCE map tracks to track the
+ * map regions allocated to us by the firmware. Cannot
+ * dynamically allocate them, since the heap is not set
+ * yet.
+ */
+struct grub_map_track  grub_map_track[IEEE1275_MAX_MAP_RESOURCE];
+int grub_map_track_index=0;
+
+void
+grub_releasemap ()
+{
+  int i=0;
+  for (i=grub_map_track_index-1; i >= 0; i--)
+   grub_ieee1275_release(grub_map_track[i].addr, grub_map_track[i].size);
+  grub_map_track_index = 0;
+  return;
+}
+
+static void
+grub_track_map (grub_addr_t addr, grub_size_t size)
+{
+  if (grub_map_track_index >= IEEE1275_MAX_MAP_RESOURCE)
+   return;
+  grub_map_track[grub_map_track_index].addr = addr;
+  grub_map_track[grub_map_track_index++].size = size;
+  return;
+}
+
 grub_err_t
 grub_claimmap (grub_addr_t addr, grub_size_t size)
 {
@@ -317,6 +345,7 @@ grub_claimmap (grub_addr_t addr, grub_size_t size)
       return grub_errno;
     }
 
+  grub_track_map (addr, size);
   return GRUB_ERR_NONE;
 }
 
diff --git a/include/grub/ieee1275/ieee1275.h b/include/grub/ieee1275/ieee1275.h
index be0c235..254c05c 100644
--- a/include/grub/ieee1275/ieee1275.h
+++ b/include/grub/ieee1275/ieee1275.h
@@ -30,6 +30,12 @@ struct grub_ieee1275_mem_region
   unsigned int size;
 };
 
+#define IEEE1275_MAX_MAP_RESOURCE 256
+struct grub_map_track {
+  grub_addr_t addr;
+  grub_size_t size;
+};
+
 #define IEEE1275_MAX_PROP_LEN  8192
 #define IEEE1275_MAX_PATH_LEN  256
 
@@ -215,6 +221,7 @@ int EXPORT_FUNC(grub_ieee1275_milliseconds) (grub_uint32_t 
*msecs);
 
 
 grub_err_t EXPORT_FUNC(grub_claimmap) (grub_addr_t addr, grub_size_t size);
+void EXPORT_FUNC(grub_releasemap) (void);
 
 int
 EXPORT_FUNC(grub_ieee1275_map) (grub_addr_t phys, grub_addr_t virt,
-- 
1.8.3.1