File kexec-tools-ppc-check-flags.diff of Package kexec-tools

From: Chandru <chandru@in.ibm.com>
Subject: kdump: check flags field from drconf memory
References: bnc#438086
X-Git-Id: 802a8a5e396e06a514251c44454c982bff3c5073

On a powerpc machine when memory is dynamically removed/added from an lpar, the
corresponding flags field in the drconf memory reflects the same with the bits
unset/set accordingly. The kernel does a check on these flags while booting.
Following are the similar changes brought in to kexec-tools.  This makes
kexec-tools to skip those memory regions that do not belong or are not
assigned to the current partition ( but are available to dynamically add them
back ). Without this patch (and with memory remove operation) copying vmcore
fails with error as

Copying data                       : [ 84 %] readmem: Can't read the dump
memory(/proc/vmcore). Bad address
read_pfn: Can't get the page data.


Signed-off-by : Chandru S <chandru@in.ibm.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Bernhard Walle <bwalle@suse.de>

---
 kexec/arch/ppc64/crashdump-ppc64.c |   12 ++++++++++--
 kexec/arch/ppc64/crashdump-ppc64.h |    3 +++
 2 files changed, 13 insertions(+), 2 deletions(-)

--- a/kexec/arch/ppc64/crashdump-ppc64.c
+++ b/kexec/arch/ppc64/crashdump-ppc64.c
@@ -121,12 +121,13 @@ static void exclude_crash_region(uint64_
 	}
 }
 
-static int get_dyn_reconf_crash_memory_ranges()
+static int get_dyn_reconf_crash_memory_ranges(void)
 {
 	uint64_t start, end;
 	char fname[128], buf[32];
 	FILE *file;
 	int i, n;
+	uint32_t flags;
 
 	strcpy(fname, "/proc/device-tree/");
 	strcat(fname, "ibm,dynamic-reconfiguration-memory/ibm,dynamic-memory");
@@ -150,10 +151,17 @@ static int get_dyn_reconf_crash_memory_r
 			return -1;
 		}
 
-		start = ((uint64_t *)buf)[0];
+		start = ((uint64_t *)buf)[DRCONF_ADDR];
 		end = start + lmb_size;
 		if (start == 0 && end >= (BACKUP_SRC_END + 1))
 			start = BACKUP_SRC_END + 1;
+
+		flags = (*((uint32_t *)&buf[DRCONF_FLAGS]));
+		/* skip this block if the reserved bit is set in flags (0x80)
+		   or if the block is not assigned to this partition (0x8) */
+		if ((flags & 0x80) || !(flags & 0x8))
+			continue;
+
 		exclude_crash_region(start, end);
 	}
 	fclose(file);
--- a/kexec/arch/ppc64/crashdump-ppc64.h
+++ b/kexec/arch/ppc64/crashdump-ppc64.h
@@ -31,4 +31,7 @@ extern unsigned int rtas_size;
 uint64_t lmb_size;
 unsigned int num_of_lmbs;
 
+#define DRCONF_ADDR	0
+#define DRCONF_FLAGS	20
+
 #endif /* CRASHDUMP_PPC64_H */