[PATCH 2/3] [kexec-tools] Pass vmcoreinfo's address and size

From: "Ken'ichi Ohmichi" <oomichi@mxs.nes.nec.co.jp>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Don Zickus <dzickus@redhat.com>, Neil Horman <nhorman@redhat.com>,
	Dan Aloni <da-x@monatomic.org>, Bernhard Walle <bwalle@suse.de>,
	kexec-ml <kexec@lists.infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Vivek Goyal <vgoyal@in.ibm.com>
Subject: [PATCH 2/3] [kexec-tools] Pass vmcoreinfo's address and size
Date: Wed, 22 Aug 2007 21:13:39 +0900	[thread overview]
Message-ID: <20070822211339oomichi@mail.jp.nec.com> (raw)
In-Reply-To: <20070822210838oomichi@mail.jp.nec.com>


[2/3] [kexec-tools] 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/)
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.


Thanks
Ken'ichi Ohmichi

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

---
diff -rpuN backup/kexec-tools-testing-20070330/kexec/crashdump-elf.c kexec-tools/kexec/crashdump-elf.c

--- backup/kexec-tools-testing-20070330/kexec/crashdump-elf.c	2007-03-30 13:34:36.000000000 +0900
+++ kexec-tools/kexec/crashdump-elf.c	2007-08-03 14:45:47.000000000 +0900
@@ -36,6 +36,8 @@ int FUNC(struct kexec_info *info,
 	char *bufp;
 	long int nr_cpus = 0;
 	uint64_t notes_addr, notes_len;
+	uint64_t vmcoreinfo_addr, vmcoreinfo_len;
+	int has_vmcoreinfo = 0;
 	int (*get_note_info)(int cpu, uint64_t *addr, uint64_t *len);
 
 	if (xen_present())
@@ -47,7 +49,11 @@ int FUNC(struct kexec_info *info,
 		return -1;
 	}
 
-	sz = sizeof(EHDR) + nr_cpus * sizeof(PHDR) + ranges * sizeof(PHDR);
+	if (get_kernel_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len) == 0) {
+		has_vmcoreinfo = 1;
+	}
+
+	sz = sizeof(EHDR) + (nr_cpus + has_vmcoreinfo) * sizeof(PHDR) + ranges * sizeof(PHDR);
 
 	/*
 	 * Certain architectures such as x86_64 and ia64 require a separate
@@ -148,6 +154,21 @@ int FUNC(struct kexec_info *info,
 		dfprintf_phdr(stdout, "Elf header", phdr);
 	}
 
+	if (has_vmcoreinfo) {
+		phdr = (PHDR *) bufp;
+		bufp += sizeof(PHDR);
+		phdr->p_type	= PT_NOTE;
+		phdr->p_flags	= 0;
+		phdr->p_offset  = phdr->p_paddr = vmcoreinfo_addr;
+		phdr->p_vaddr   = 0;
+		phdr->p_filesz	= phdr->p_memsz	= vmcoreinfo_len;
+		/* Do we need any alignment of segments? */
+		phdr->p_align	= 0;
+
+		(elf->e_phnum)++;
+		dfprintf_phdr(stdout, "vmcoreinfo header", phdr);
+	}
+
 	/* Setup an PT_LOAD type program header for the region where
 	 * Kernel is mapped if info->kern_size is non-zero.
 	 */
diff -rpuN backup/kexec-tools-testing-20070330/kexec/crashdump.c kexec-tools/kexec/crashdump.c
--- backup/kexec-tools-testing-20070330/kexec/crashdump.c	2007-03-30 13:34:36.000000000 +0900
+++ kexec-tools/kexec/crashdump.c	2007-08-03 14:45:05.000000000 +0900
@@ -108,3 +108,35 @@ int get_crash_notes_per_cpu(int cpu, uin
 
 	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;
+}
diff -rpuN backup/kexec-tools-testing-20070330/kexec/crashdump.h kexec-tools/kexec/crashdump.h
--- backup/kexec-tools-testing-20070330/kexec/crashdump.h	2007-03-30 13:34:36.000000000 +0900
+++ kexec-tools/kexec/crashdump.h	2007-08-03 14:45:05.000000000 +0900
@@ -2,6 +2,7 @@
 #define CRASHDUMP_H
 
 extern int get_crash_notes_per_cpu(int cpu, uint64_t *addr, uint64_t *len);
+extern int get_kernel_vmcoreinfo(uint64_t *addr, uint64_t *len);
 
 /* Need to find a better way to determine per cpu notes section size. */
 #define MAX_NOTE_BYTES		1024
_

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