From: Zhen Lei Date: Wed, 16 Nov 2022 12:10:44 +0000 (+0800) Subject: arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a9ae89df737756d92f0e14873339cf393f7f7eb0;p=linux.git 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: Zhen Lei Acked-by: Baoquan He Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20221116121044.1690-3-thunder.leizhen@huawei.com Signed-off-by: Will Deacon --- diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6c6fafc3fba9b..9d458dfbec5f1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -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. diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index ba7227179822d..58a0bb2c17f18 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -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;