Commit 32105f7f authored by Bernhard Walle's avatar Bernhard Walle Committed by Ingo Molnar
Browse files

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: default avatarBernhard Walle <bwalle@suse.de>
Cc: vgoyal@redhat.com
Cc: Bernhard Walle <bwalle@suse.de>
Cc: kexec@lists.infradead.org
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent fd6493e1

arch/x86/kernel/setup.c

+52 −18
Original line number Diff line number Diff line
@@ -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;
@@ -444,19 +472,26 @@ 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 (ret != 0 || crash_size <= 0)

		return;



	/* 0 means: find the address automatically */

	if (crash_base <= 0) {

			printk(KERN_INFO "crashkernel reservation failed - "

					"you have to specify a base address\n");

		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 - "

	} 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",
@@ -468,7 +503,6 @@ static void __init reserve_crashkernel(void) 
	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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