Pass vmcoreinfo's address and size

The patch is for kexec-tools-testing-20070330.
(http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/)

The kexec command gets the address and size of the vmcoreinfo data from
/sys/kernel/vmcoreinfo, and passes them to the second kernel through
ELF header of /proc/vmcore. When the second kernel is booting, the
kernel gets them from the ELF header and creates vmcoreinfo's PT_NOTE
segment into /proc/vmcore.

Signed-off-by: Dan Aloni <da-x@monatomic.org>
Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 32 insertions, 0 deletions

diff --git a/kexec/crashdump.c b/kexec/crashdump.c
index 1c08606..a35f7a7 100644
--- a/kexec/crashdump.c
+++ b/kexec/crashdump.c
@@ -108,3 +108,35 @@ int get_crash_notes_per_cpu(int cpu, uint64_t *addr, uint64_t *len)
 
 	return 0;
 }
+
+/* Returns the physical address of start of crash notes buffer for a kernel. */
+int get_kernel_vmcoreinfo(uint64_t *addr, uint64_t *len)
+{
+	char kdump_info[PATH_MAX];
+	char line[MAX_LINE];
+	int count;
+	FILE *fp;
+	unsigned long long temp, temp2;
+
+	*addr = 0;
+	*len = 0;
+
+	sprintf(kdump_info, "/sys/kernel/vmcoreinfo");
+	fp = fopen(kdump_info, "r");
+	if (!fp) {
+		die("Could not open \"%s\": %s\n", kdump_info,
+		    strerror(errno));
+		return -1;
+	}
+
+	if (!fgets(line, sizeof(line), fp))
+		die("Cannot parse %s: %s\n", kdump_info, strerror(errno));
+	count = sscanf(line, "%Lx %Lx", &temp, &temp2);
+	if (count != 2)
+		die("Cannot parse %s: %s\n", kdump_info, strerror(errno));
+
+	*addr = (uint64_t) temp;
+	*len = (uint64_t) temp2;
+
+	return 0;
+}