From 5f5609df0c943b005847d3b2765d6dd47b624011 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 25 Jun 2005 14:58:04 -0700 Subject: [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/setup.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'arch/x86_64/kernel/setup.c') 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 #include #include +#include #include #include @@ -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(); -- cgit v1.2.2