[IA64] Merge overlapping reserved regions at boot
While working on the upcoming SLES11 SP2, I ran into an issue with booting the
panic kernel on a kernel crash. In the first iteration I found out that the
initial register backing store gets overwritten with zeroes, causing a kernel
crash shortly afterwards.
Further investigation revealed that rsvd_region[] contains overlapping
entries: find_memmap_space() returns a pointer which lies between KERNEL_START
and _end. This is correct with the EFI memmap as patched by the kexec
purgatory code. That code removes vmlinux LOAD segments from the usable map,
but there is a pretty large hole between the gate section and the per-cpu
section.
This happens because reserve_memory() blindly marks [KERNEL_START, __end]
as reserved, even though there is a free block in the middle in the kexec
case because it noticed a large gap between sections and modified the
efi_memory_map to account for this.
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index 5e2c724..cd57d73 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -220,6 +220,23 @@
}
}
+/* merge overlaps */
+static int __init
+merge_regions (struct rsvd_region *rsvd_region, int max)
+{
+ int i;
+ for (i = 1; i < max; ++i) {
+ if (rsvd_region[i].start >= rsvd_region[i-1].end)
+ continue;
+ if (rsvd_region[i].end > rsvd_region[i-1].end)
+ rsvd_region[i-1].end = rsvd_region[i].end;
+ --max;
+ memmove(&rsvd_region[i], &rsvd_region[i+1],
+ (max - i) * sizeof(struct rsvd_region));
+ }
+ return max;
+}
+
/*
* Request address space for all standard resources
*/
@@ -270,6 +287,7 @@
if (ret == 0 && size > 0) {
if (!base) {
sort_regions(rsvd_region, *n);
+ *n = merge_regions(rsvd_region, *n);
base = kdump_find_rsvd_region(size,
rsvd_region, *n);
}
@@ -373,6 +391,7 @@
BUG_ON(IA64_MAX_RSVD_REGIONS + 1 < n);
sort_regions(rsvd_region, num_rsvd_regions);
+ num_rsvd_regions = merge_regions(rsvd_region, num_rsvd_regions);
}