Commit 55a20ee7 authored by Yinghai Lu's avatar Yinghai Lu Committed by H. Peter Anvin
Browse files

x86, kdump: Retore crashkernel= to allocate under 896M 



Vivek found old kexec-tools does not work new kernel anymore.

So change back crashkernel= back to old behavoir, and add crashkernel_high=
to let user decide if buffer could be above 4G, and also new kexec-tools will
be needed.

-v2: let crashkernel=X override crashkernel_high=
    update description about _high will be ignored by crashkernel=X
-v3: update description about kernel-parameters.txt according to Vivek.

Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1366089828-19692-4-git-send-email-yinghai@kernel.org


Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent c729de8f

Documentation/kernel-parameters.txt

+11 −2
Original line number Diff line number Diff line
@@ -603,9 +603,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			a memory unit (amount[KMG]). See also

			Documentation/kdump/kdump.txt for an example.



	crashkernel_high=size[KMG]

			[KNL, x86_64] range could be above 4G. Allow kernel

			to allocate physical memory region from top, so could

			be above 4G if system have more than 4G ram installed.

			Otherwise memory region will be allocated below 4G, if

			available.

			It will be ignored if crashkernel=X is specified.

	crashkernel_low=size[KMG]

			[KNL, x86_64] range under 4G. When crashkernel= is

			passed, kernel allocate physical memory region

			[KNL, x86_64] range under 4G. When crashkernel_high= is

			passed, kernel could allocate physical memory region

			above 4G, that cause second kernel crash on system

			that require some amount of low memory, e.g. swiotlb

			requires at least 64M+32K low memory.  Kernel would
@@ -613,6 +620,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			This one let user to specify own low range under 4G

			for second kernel instead.

			0: to disable low allocation.

			It will be ignored when crashkernel_high=X is not used

			or memory reserved is below 4G.



	cs89x0_dma=	[HW,NET]

			Format: <dma>

arch/x86/kernel/setup.c

+19 −5
Original line number Diff line number Diff line
@@ -507,11 +507,14 @@ static void __init memblock_x86_reserve_range_setup_data(void) 
/*

 * Keep the crash kernel below this limit.  On 32 bits earlier kernels

 * would limit the kernel to the low 512 MiB due to mapping restrictions.

 * On 64bit, old kexec-tools need to under 896MiB.

 */

#ifdef CONFIG_X86_32

# define CRASH_KERNEL_ADDR_MAX	(512 << 20)

# define CRASH_KERNEL_ADDR_LOW_MAX	(512 << 20)

# define CRASH_KERNEL_ADDR_HIGH_MAX	(512 << 20)

#else

# define CRASH_KERNEL_ADDR_MAX	MAXMEM

# define CRASH_KERNEL_ADDR_LOW_MAX	(896UL<<20)

# define CRASH_KERNEL_ADDR_HIGH_MAX	MAXMEM

#endif



static void __init reserve_crashkernel_low(void)
@@ -525,6 +528,7 @@ static void __init reserve_crashkernel_low(void) 
	int ret;



	total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));

	/* crashkernel_low=YM */

	ret = parse_crashkernel_low(boot_command_line, total_low_mem,

						&low_size, &base);

	if (ret != 0) {
@@ -569,14 +573,22 @@ static void __init reserve_crashkernel(void) 
	const unsigned long long alignment = 16<<20;	/* 16M */

	unsigned long long total_mem;

	unsigned long long crash_size, crash_base;

	bool high = false;

	int ret;



	total_mem = memblock_phys_mem_size();



	/* crashkernel=XM */

	ret = parse_crashkernel(boot_command_line, total_mem,

			&crash_size, &crash_base);

	if (ret != 0 || crash_size <= 0) {

		/* crashkernel_high=XM */

		ret = parse_crashkernel_high(boot_command_line, total_mem,

				&crash_size, &crash_base);

		if (ret != 0 || crash_size <= 0)

			return;

		high = true;

	}



	/* 0 means: find the address automatically */

	if (crash_base <= 0) {
@@ -584,7 +596,9 @@ static void __init reserve_crashkernel(void) 
		 *  kexec want bzImage is below CRASH_KERNEL_ADDR_MAX

		 */

		crash_base = memblock_find_in_range(alignment,

			       CRASH_KERNEL_ADDR_MAX, crash_size, alignment);

					high ? CRASH_KERNEL_ADDR_HIGH_MAX :

					       CRASH_KERNEL_ADDR_LOW_MAX,

					crash_size, alignment);



		if (!crash_base) {

			pr_info("crashkernel reservation failed - No suitable area found.\n");

include/linux/kexec.h

+2 −0
Original line number Diff line number Diff line
@@ -200,6 +200,8 @@ extern size_t vmcoreinfo_max_size; 


int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,

		unsigned long long *crash_size, unsigned long long *crash_base);

int parse_crashkernel_high(char *cmdline, unsigned long long system_ram,

		unsigned long long *crash_size, unsigned long long *crash_base);

int parse_crashkernel_low(char *cmdline, unsigned long long system_ram,

		unsigned long long *crash_size, unsigned long long *crash_base);

int crash_shrink_memory(unsigned long new_size);

kernel/kexec.c

+9 −0
Original line number Diff line number Diff line
@@ -1422,6 +1422,15 @@ int __init parse_crashkernel(char *cmdline, 
					"crashkernel=");

}



int __init parse_crashkernel_high(char *cmdline,

			     unsigned long long system_ram,

			     unsigned long long *crash_size,

			     unsigned long long *crash_base)

{

	return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,

					"crashkernel_high=");

}



int __init parse_crashkernel_low(char *cmdline,

			     unsigned long long system_ram,

			     unsigned long long *crash_size,

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