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authorBernhard Walle <bwalle@suse.de>2008-06-26 21:54:08 +0200
committerIngo Molnar <mingo@elte.hu>2008-07-08 13:16:18 +0200
commit32105f7fd8faa7bc3d101dcc3eabc0ae1ac375a7 (patch)
treeff6bcff32e3641b2c4c2c98c242dc4803eddf3f9
parentfd6493e16625b92a506fba13deda31c0be5f1cd4 (diff)
x86: find offset for crashkernel reservation automatically
This patch removes the need of the crashkernel=...@offset parameter to define a fixed offset for crashkernel reservation. That feature can be used together with a relocatable kernel where the kexec-tools relocate the kernel and get the actual offset from /proc/iomem. The use case is a kernel where the .text+.data+.bss is after 16M physical memory (debug kernel with lockdep on x86_64 can cause that) which caused a major pain in autoconfiguration in our distribution. Also, that patch unifies crashdump architectures a bit since IA64 has that semantics from the very beginning of the kdump port. Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: vgoyal@redhat.com Cc: Bernhard Walle <bwalle@suse.de> Cc: kexec@lists.infradead.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/kernel/setup.c70
1 files changed, 52 insertions, 18 deletions
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 2ca12d4c88fb..b3469898717e 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -422,6 +422,34 @@ static void __init reserve_setup_data(void)
*/
#ifdef CONFIG_KEXEC
+
+/**
+ * Reserve @size bytes of crashkernel memory at any suitable offset.
+ *
+ * @size: Size of the crashkernel memory to reserve.
+ * Returns the base address on success, and -1ULL on failure.
+ */
+unsigned long long find_and_reserve_crashkernel(unsigned long long size)
+{
+ const unsigned long long alignment = 16<<20; /* 16M */
+ unsigned long long start = 0LL;
+
+ while (1) {
+ int ret;
+
+ start = find_e820_area(start, ULONG_MAX, size, alignment);
+ if (start == -1ULL)
+ return start;
+
+ /* try to reserve it */
+ ret = reserve_bootmem_generic(start, size, BOOTMEM_EXCLUSIVE);
+ if (ret >= 0)
+ return start;
+
+ start += alignment;
+ }
+}
+
static inline unsigned long long get_total_mem(void)
{
unsigned long long total;
@@ -444,30 +472,36 @@ static void __init reserve_crashkernel(void)
ret = parse_crashkernel(boot_command_line, total_mem,
&crash_size, &crash_base);
- if (ret == 0 && crash_size > 0) {
- if (crash_base <= 0) {
- printk(KERN_INFO "crashkernel reservation failed - "
- "you have to specify a base address\n");
+ if (ret != 0 || crash_size <= 0)
+ return;
+
+ /* 0 means: find the address automatically */
+ if (crash_base <= 0) {
+ crash_base = find_and_reserve_crashkernel(crash_size);
+ if (crash_base == -1ULL) {
+ pr_info("crashkernel reservation failed. "
+ "No suitable area found.\n");
return;
}
-
- if (reserve_bootmem_generic(crash_base, crash_size,
- BOOTMEM_EXCLUSIVE) < 0) {
- printk(KERN_INFO "crashkernel reservation failed - "
- "memory is in use\n");
+ } else {
+ ret = reserve_bootmem_generic(crash_base, crash_size,
+ BOOTMEM_EXCLUSIVE);
+ if (ret < 0) {
+ pr_info("crashkernel reservation failed - "
+ "memory is in use\n");
return;
}
+ }
- printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
- "for crashkernel (System RAM: %ldMB)\n",
- (unsigned long)(crash_size >> 20),
- (unsigned long)(crash_base >> 20),
- (unsigned long)(total_mem >> 20));
+ printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
+ "for crashkernel (System RAM: %ldMB)\n",
+ (unsigned long)(crash_size >> 20),
+ (unsigned long)(crash_base >> 20),
+ (unsigned long)(total_mem >> 20));
- crashk_res.start = crash_base;
- crashk_res.end = crash_base + crash_size - 1;
- insert_resource(&iomem_resource, &crashk_res);
- }
+ crashk_res.start = crash_base;
+ crashk_res.end = crash_base + crash_size - 1;
+ insert_resource(&iomem_resource, &crashk_res);
}
#else
static void __init reserve_crashkernel(void)

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