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x86: find offset for crashkernel reservation automatically

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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>
This commit is contained in:
Bernhard Walle
2008-06-26 21:54:08 +02:00
committed by Ingo Molnar
parent fd6493e166
commit 32105f7fd8
1 changed files with 53 additions and 19 deletions
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72
arch/x86/kernel/setup.c
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@@ -422,6 +422,34 @@ static void __init reserve_setup_data(void)
*/ */
#ifdef CONFIG_KEXEC #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) static inline unsigned long long get_total_mem(void)
{ {
unsigned long long total; unsigned long long total;
@@ -444,30 +472,36 @@ static void __init reserve_crashkernel(void)
ret = parse_crashkernel(boot_command_line, total_mem, ret = parse_crashkernel(boot_command_line, total_mem,
&crash_size, &crash_base); &crash_size, &crash_base);
if (ret == 0 && crash_size > 0) { if (ret != 0 || crash_size <= 0)
if (crash_base <= 0) { return;
printk(KERN_INFO "crashkernel reservation failed - "
"you have to specify a base address\n"); /* 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; return;
} }
} else {
if (reserve_bootmem_generic(crash_base, crash_size, ret = reserve_bootmem_generic(crash_base, crash_size,
BOOTMEM_EXCLUSIVE) < 0) { BOOTMEM_EXCLUSIVE);
printk(KERN_INFO "crashkernel reservation failed - " if (ret < 0) {
"memory is in use\n"); pr_info("crashkernel reservation failed - "
"memory is in use\n");
return; 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));
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
insert_resource(&iomem_resource, &crashk_res);
} }
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);
} }
#else #else
static void __init reserve_crashkernel(void) static void __init reserve_crashkernel(void)