From 8f0f104e2ab6eed4cad3b111dc206f843bda43ea Mon Sep 17 00:00:00 2001 From: Zhen Lei Date: Wed, 11 May 2022 11:20:32 +0800 Subject: arm64: kdump: Do not allocate crash low memory if not needed When "crashkernel=X,high" is specified, the specified "crashkernel=Y,low" memory is not required in the following corner cases: 1. If both CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32 are disabled, it means that the devices can access any memory. 2. If the system memory is small, the crash high memory may be allocated from the DMA zones. If that happens, there's no need to allocate another crash low memory because there's already one. Add condition '(crash_base >= CRASH_ADDR_LOW_MAX)' to determine whether the 'high' memory is allocated above DMA zones. Note: when both CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32 are disabled, the entire physical memory is DMA accessible, CRASH_ADDR_LOW_MAX equals 'PHYS_MASK + 1'. Signed-off-by: Zhen Lei Acked-by: Baoquan He Link: https://lore.kernel.org/r/20220511032033.426-1-thunder.leizhen@huawei.com Signed-off-by: Catalin Marinas --- arch/arm64/mm/init.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/arm64/mm/init.c') diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 18ba66c90991..ac510fb6a2c0 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -170,7 +170,8 @@ static void __init reserve_crashkernel(void) return; } - if (crash_low_size && reserve_crashkernel_low(crash_low_size)) { + if ((crash_base >= CRASH_ADDR_LOW_MAX) && + crash_low_size && reserve_crashkernel_low(crash_low_size)) { memblock_phys_free(crash_base, crash_size); return; } -- cgit