From 76d71ebddf23e8195dd5f7889cb2844530689907 Mon Sep 17 00:00:00 2001 From: Petr Tesarik Date: Tue, 29 Nov 2011 15:01:51 +0100 Subject: [PATCH] [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 Signed-off-by: Tony Luck --- arch/ia64/kernel/setup.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c index 5e2c72498c51..cd57d7312de0 100644 --- a/arch/ia64/kernel/setup.c +++ b/arch/ia64/kernel/setup.c @@ -220,6 +220,23 @@ sort_regions (struct rsvd_region *rsvd_region, int max) } } +/* 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 @@ static void __init setup_crashkernel(unsigned long total, int *n) 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 @@ reserve_memory (void) 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); } -- 2.39.5