diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2020-11-18 18:58:09 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-11-19 17:58:55 +0000 |
| commit | 791ab8b2e3db0c6e4295467d10398800ec29144c (patch) | |
| tree | 51283134e74f2dba393926e735e47e3b6e90b282 /arch/arm64/mm/init.c | |
| parent | f8394f232b1eab649ce2df5c5f15b0e528c92091 (diff) | |
arm64: Ignore any DMA offsets in the max_zone_phys() calculation
Currently, the kernel assumes that if RAM starts above 32-bit (or
zone_bits), there is still a ZONE_DMA/DMA32 at the bottom of the RAM and
such constrained devices have a hardwired DMA offset. In practice, we
haven't noticed any such hardware so let's assume that we can expand
ZONE_DMA32 to the available memory if no RAM below 4GB. Similarly,
ZONE_DMA is expanded to the 4GB limit if no RAM addressable by
zone_bits.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20201118185809.1078362-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm/init.c')
| -rw-r--r-- | arch/arm64/mm/init.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 095540667f0f..6be62c5bc0a3 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -175,14 +175,21 @@ static void __init reserve_elfcorehdr(void) #endif /* CONFIG_CRASH_DUMP */ /* - * Return the maximum physical address for a zone with a given address size - * limit. It currently assumes that for memory starting above 4G, 32-bit - * devices will use a DMA offset. + * Return the maximum physical address for a zone accessible by the given bits + * limit. If DRAM starts above 32-bit, expand the zone to the maximum + * available memory, otherwise cap it at 32-bit. */ static phys_addr_t __init max_zone_phys(unsigned int zone_bits) { - phys_addr_t offset = memblock_start_of_DRAM() & GENMASK_ULL(63, zone_bits); - return min(offset + (1ULL << zone_bits), memblock_end_of_DRAM()); + phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits); + phys_addr_t phys_start = memblock_start_of_DRAM(); + + if (phys_start > U32_MAX) + zone_mask = PHYS_ADDR_MAX; + else if (phys_start > zone_mask) + zone_mask = U32_MAX; + + return min(zone_mask, memblock_end_of_DRAM() - 1) + 1; } static void __init zone_sizes_init(unsigned long min, unsigned long max) |