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authorEric W. Biederman <ebiederm@xmission.com>2005-06-26 01:58:04 +0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-26 03:24:50 +0400
commit5f5609df0c943b005847d3b2765d6dd47b624011 (patch)
treef994509dc8b507b9392bcf632c4df2a0261a9f5f
parent5234f5eb04abbbfa306ccfbc2ccbb6e73f515b15 (diff)
downloadlinux-5f5609df0c943b005847d3b2765d6dd47b624011.tar.xz
[PATCH] crashdump: x86_64: crashkernel option
This is the x86_64 implementation of the crashkernel option. It reserves a window of memory very early in the bootup process, so we never use it for anything but the kernel to switch to when the running kernel panics. In addition to reserving this memory a resource structure is registered so looking at /proc/iomem it is clear what happened to that memory. ISSUES: Is it possible to implement this in a architecture generic way? What should be done with architectures that always use an iommu and thus don't report their RAM memory resources in /proc/iomem? Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/x86_64/kernel/e820.c4
-rw-r--r--arch/x86_64/kernel/setup.c29
2 files changed, 33 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
index cf4878309b04..6ded3a50dfe6 100644
--- a/arch/x86_64/kernel/e820.c
+++ b/arch/x86_64/kernel/e820.c
@@ -16,6 +16,7 @@
#include <linux/bootmem.h>
#include <linux/ioport.h>
#include <linux/string.h>
+#include <linux/kexec.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/proto.h>
@@ -210,6 +211,9 @@ void __init e820_reserve_resources(void)
*/
request_resource(res, &code_resource);
request_resource(res, &data_resource);
+#ifdef CONFIG_KEXEC
+ request_resource(res, &crashk_res);
+#endif
}
}
}
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index ca9a915a6d4a..b02d921da4f7 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -41,6 +41,7 @@
#include <linux/kallsyms.h>
#include <linux/edd.h>
#include <linux/mmzone.h>
+#include <linux/kexec.h>
#include <asm/mtrr.h>
#include <asm/uaccess.h>
@@ -367,6 +368,27 @@ static __init void parse_cmdline_early (char ** cmdline_p)
if (!memcmp(from, "noexec=", 7))
nonx_setup(from + 7);
+#ifdef CONFIG_KEXEC
+ /* crashkernel=size@addr specifies the location to reserve for
+ * a crash kernel. By reserving this memory we guarantee
+ * that linux never set's it up as a DMA target.
+ * Useful for holding code to do something appropriate
+ * after a kernel panic.
+ */
+ else if (!memcmp(from, "crashkernel=", 12)) {
+ unsigned long size, base;
+ size = memparse(from+12, &from);
+ if (*from == '@') {
+ base = memparse(from+1, &from);
+ /* FIXME: Do I want a sanity check
+ * to validate the memory range?
+ */
+ crashk_res.start = base;
+ crashk_res.end = base + size - 1;
+ }
+ }
+#endif
+
next_char:
c = *(from++);
if (!c)
@@ -625,6 +647,13 @@ void __init setup_arch(char **cmdline_p)
#endif
sparse_init();
+
+#ifdef CONFIG_KEXEC
+ if (crashk_res.start != crashk_res.end) {
+ reserve_bootmem(crashk_res.start,
+ crashk_res.end - crashk_res.start + 1);
+ }
+#endif
paging_init();
check_ioapic();