Commit 926939c7 authored by Will Deacon's avatar Will Deacon
Browse files

Merge branch 'for-next/kdump' into for-next/core 

* for-next/kdump:
  arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones
  arm64: kdump: Provide default size when crashkernel=Y,low is not specified
parents d864e905 a9ae89df

Documentation/admin-guide/kernel-parameters.txt

+6 −9
Original line number Diff line number Diff line
@@ -831,7 +831,7 @@ 
			memory region [offset, offset + size] for that kernel

			image. If '@offset' is omitted, then a suitable offset

			is selected automatically.

			[KNL, X86-64] Select a region under 4G first, and

			[KNL, X86-64, ARM64] Select a region under 4G first, and

			fall back to reserve region above 4G when '@offset'

			hasn't been specified.

			See Documentation/admin-guide/kdump/kdump.rst for further details.
@@ -851,26 +851,23 @@ 
			available.

			It will be ignored if crashkernel=X is specified.

	crashkernel=size[KMG],low

			[KNL, X86-64] range under 4G. When crashkernel=X,high

			[KNL, X86-64, ARM64] range under 4G. When crashkernel=X,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, also enough extra

			low memory is needed to make sure DMA buffers for 32-bit

			devices won't run out. Kernel would try to allocate

			at least 256M below 4G automatically.

			default	size of memory below 4G automatically. The default

			size is	platform dependent.

			  --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)

			  --> arm64: 128MiB

			This one lets the user specify own low range under 4G

			for second kernel instead.

			0: to disable low allocation.

			It will be ignored when crashkernel=X,high is not used

			or memory reserved is below 4G.



			[KNL, ARM64] range in low memory.

			This one lets the user specify a low range in the

			DMA zone for the crash dump kernel.

			It will be ignored when crashkernel=X,high is not used

			or memory reserved is located in the DMA zones.



	cryptomgr.notests

			[KNL] Disable crypto self-tests

arch/arm64/mm/init.c

+22 −3
Original line number Diff line number Diff line
@@ -96,6 +96,8 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1; 
#define CRASH_ADDR_LOW_MAX		arm64_dma_phys_limit

#define CRASH_ADDR_HIGH_MAX		(PHYS_MASK + 1)



#define DEFAULT_CRASH_KERNEL_LOW_SIZE	(128UL << 20)



static int __init reserve_crashkernel_low(unsigned long long low_size)

{

	unsigned long long low_base;
@@ -130,6 +132,7 @@ static void __init reserve_crashkernel(void) 
	unsigned long long crash_max = CRASH_ADDR_LOW_MAX;

	char *cmdline = boot_command_line;

	int ret;

	bool fixed_base = false;



	if (!IS_ENABLED(CONFIG_KEXEC_CORE))

		return;
@@ -147,7 +150,9 @@ static void __init reserve_crashkernel(void) 
		 * is not allowed.

		 */

		ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);

		if (ret && (ret != -ENOENT))

		if (ret == -ENOENT)

			crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;

		else if (ret)

			return;



		crash_max = CRASH_ADDR_HIGH_MAX;
@@ -159,18 +164,32 @@ static void __init reserve_crashkernel(void) 
	crash_size = PAGE_ALIGN(crash_size);



	/* User specifies base address explicitly. */

	if (crash_base)

	if (crash_base) {

		fixed_base = true;

		crash_max = crash_base + crash_size;

	}



retry:

	crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,

					       crash_base, crash_max);

	if (!crash_base) {

		/*

		 * If the first attempt was for low memory, fall back to

		 * high memory, the minimum required low memory will be

		 * reserved later.

		 */

		if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) {

			crash_max = CRASH_ADDR_HIGH_MAX;

			crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;

			goto retry;

		}



		pr_warn("cannot allocate crashkernel (size:0x%llx)\n",

			crash_size);

		return;

	}



	if ((crash_base >= CRASH_ADDR_LOW_MAX) &&

	if ((crash_base > CRASH_ADDR_LOW_MAX - crash_low_size) &&

	     crash_low_size && reserve_crashkernel_low(crash_low_size)) {

		memblock_phys_free(crash_base, crash_size);

		return;