On Sat, Dec 26, 2020 at 11:34:58AM +0100, Nicolas Saenz Julienne wrote: > On Sat, 2020-12-26 at 11:35 +0800, Chen Zhou wrote: > > If the memory reserved for crash dump kernel falled in ZONE_DMA32, > > the devices in crash dump kernel need to use ZONE_DMA will alloc fail. > > > > Fix this by reserving low memory in ZONE_DMA if CONFIG_ZONE_DMA is > > enabled, otherwise, reserving in ZONE_DMA32. > > > > Fixes: bff3b04460a8 ("arm64: mm: reserve CMA and crashkernel in ZONE_DMA32") > > I'm not so sure this counts as a fix, if someone backports it it'll probably > break things as it depends on the series that dynamically sizes DMA zones. > > > Signed-off-by: Chen Zhou <chenzho...@huawei.com> > > --- > > Why not doing the same with CMA? You'll probably have to move the > dma_contiguous_reserve() call into bootmem_init() so as to make sure that > arm64_dma_phys_limit is populated.
Do we need the arm64_dma32_phys_limit at all? I can see the (arm64_dma_phys_limit ? : arm64_dma32_phys_limit) pattern in several places but I think we can just live with the arm64_dma_phys_limit. Also, I don't think we need any early ARCH_LOW_ADDRESS_LIMIT. It's only used by memblock_alloc_low() and that's called from swiotlb_init() after arm64_dma_phys_limit was initialised. What about something like below (on top of you ARCH_LOW_ADDRESS_LIMIT fix but I can revert that)? I haven't tested it in all configurations yet. diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 69ad25fbeae4..ca2cd75d3286 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -94,8 +94,7 @@ #endif /* CONFIG_ARM64_FORCE_52BIT */ extern phys_addr_t arm64_dma_phys_limit; -extern phys_addr_t arm64_dma32_phys_limit; -#define ARCH_LOW_ADDRESS_LIMIT ((arm64_dma_phys_limit ? : arm64_dma32_phys_limit) - 1) +#define ARCH_LOW_ADDRESS_LIMIT (arm64_dma_phys_limit - 1) struct debug_info { #ifdef CONFIG_HAVE_HW_BREAKPOINT diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 7deddf56f7c3..596a94bf5ed6 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -59,7 +59,6 @@ EXPORT_SYMBOL(memstart_addr); * bit addressable memory area. */ phys_addr_t arm64_dma_phys_limit __ro_after_init; -phys_addr_t arm64_dma32_phys_limit __ro_after_init; #ifdef CONFIG_KEXEC_CORE /* @@ -84,7 +83,7 @@ static void __init reserve_crashkernel(void) if (crash_base == 0) { /* Current arm64 boot protocol requires 2MB alignment */ - crash_base = memblock_find_in_range(0, arm64_dma32_phys_limit, + crash_base = memblock_find_in_range(0, arm64_dma_phys_limit, crash_size, SZ_2M); if (crash_base == 0) { pr_warn("cannot allocate crashkernel (size:0x%llx)\n", @@ -196,6 +195,7 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) unsigned long max_zone_pfns[MAX_NR_ZONES] = {0}; unsigned int __maybe_unused acpi_zone_dma_bits; unsigned int __maybe_unused dt_zone_dma_bits; + phys_addr_t dma32_phys_limit = max_zone_phys(32); #ifdef CONFIG_ZONE_DMA acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address()); @@ -205,8 +205,12 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit); #endif #ifdef CONFIG_ZONE_DMA32 - max_zone_pfns[ZONE_DMA32] = PFN_DOWN(arm64_dma32_phys_limit); + max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit); + if (!arm64_dma_phys_limit) + arm64_dma_phys_limit = dma32_phys_limit; #endif + if (!arm64_dma_phys_limit) + arm64_dma_phys_limit = PHYS_MASK + 1; max_zone_pfns[ZONE_NORMAL] = max; free_area_init(max_zone_pfns); @@ -394,16 +398,9 @@ void __init arm64_memblock_init(void) early_init_fdt_scan_reserved_mem(); - if (IS_ENABLED(CONFIG_ZONE_DMA32)) - arm64_dma32_phys_limit = max_zone_phys(32); - else - arm64_dma32_phys_limit = PHYS_MASK + 1; - reserve_elfcorehdr(); high_memory = __va(memblock_end_of_DRAM() - 1) + 1; - - dma_contiguous_reserve(arm64_dma32_phys_limit); } void __init bootmem_init(void) @@ -438,6 +435,11 @@ void __init bootmem_init(void) sparse_init(); zone_sizes_init(min, max); + /* + * Reserve the CMA area after arm64_dma_phys_limit was initialised. + */ + dma_contiguous_reserve(arm64_dma_phys_limit); + /* * request_standard_resources() depends on crashkernel's memory being * reserved, so do it here. @@ -455,7 +457,7 @@ void __init bootmem_init(void) void __init mem_init(void) { if (swiotlb_force == SWIOTLB_FORCE || - max_pfn > PFN_DOWN(arm64_dma_phys_limit ? : arm64_dma32_phys_limit)) + max_pfn > PFN_DOWN(arm64_dma_phys_limit)) swiotlb_init(1); else swiotlb_force = SWIOTLB_NO_FORCE;