Commit a9ae89df authored by Zhen Lei's avatar Zhen Lei Committed by Will Deacon
Browse files

arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones 



For crashkernel=X without '@offset', select a region within DMA zones
first, and fall back to reserve region above DMA zones. This allows
users to use the same configuration on multiple platforms.

Signed-off-by: default avatarZhen Lei <thunder.leizhen@huawei.com>
Acked-by: default avatarBaoquan He <bhe@redhat.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20221116121044.1690-3-thunder.leizhen@huawei.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent a149cf00

Documentation/admin-guide/kernel-parameters.txt

+1 −1
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.

arch/arm64/mm/init.c

+16 −1
Original line number Diff line number Diff line
@@ -132,6 +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;
@@ -163,12 +164,26 @@ 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;