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arm64: mm: Fix initialisation of DMA zones on non-NUMA systems 

John reports that the recently merged commit 1a8e1cef76 ("arm64: use
both ZONE_DMA and ZONE_DMA32") breaks the boot on his DB845C board:

  | Booting Linux on physical CPU 0x0000000000 [0x517f803c]
  | Linux version 5.4.0-mainline-10675-g957a03b9e38f
  | Machine model: Thundercomm Dragonboard 845c
  | [...]
  | Built 1 zonelists, mobility grouping on.  Total pages: -188245
  | Kernel command line: earlycon
  | firmware_class.path=/vendor/firmware/ androidboot.hardware=db845c
  | init=/init androidboot.boot_devices=soc/1d84000.ufshc
  | printk.devkmsg=on buildvariant=userdebug root=/dev/sda2
  | androidboot.bootdevice=1d84000.ufshc androidboot.serialno=c4e1189c
  | androidboot.baseband=sda
  | msm_drm.dsi_display0=dsi_lt9611_1080_video_display:
  | androidboot.slot_suffix=_a skip_initramfs rootwait ro init=/init
  |
  | <hangs indefinitely here>

This is because, when CONFIG_NUMA=n, zone_sizes_init() fails to handle
memblocks that fall entirely within the ZONE_DMA region and erroneously ends up
trying to add a negatively-sized region into the following ZONE_DMA32, which is
later interpreted as a large unsigned region by the core MM code.

Rework the non-NUMA implementation of zone_sizes_init() so that the start
address of the memblock being processed is adjusted according to the end of the
previous zone, which is then range-checked before updating the hole information
of subsequent zones.

Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/lkml/CALAqxLVVcsmFrDKLRGRq7GewcW405yTOxG=KR3csVzQ6bXutkA@mail.gmail.com
Fixes: 1a8e1cef76 ("arm64: use both ZONE_DMA and ZONE_DMA32")
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
alistair/sunxi64-5.5-dsi
Will Deacon 2019-12-03 12:10:13 +00:00 committed by Catalin Marinas
parent d8e85e144b
commit 93b90414c3
1 changed files with 11 additions and 14 deletions
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25
arch/arm64/mm/init.c
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@ -214,15 +214,14 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
{
struct memblock_region *reg;
unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
unsigned long max_dma32 = min;
unsigned long __maybe_unused max_dma = min;
unsigned long __maybe_unused max_dma, max_dma32;
memset(zone_size, 0, sizeof(zone_size));
max_dma = max_dma32 = min;
#ifdef CONFIG_ZONE_DMA
max_dma = PFN_DOWN(arm64_dma_phys_limit);
max_dma = max_dma32 = PFN_DOWN(arm64_dma_phys_limit);
zone_size[ZONE_DMA] = max_dma - min;
max_dma32 = max_dma;
#endif
#ifdef CONFIG_ZONE_DMA32
max_dma32 = PFN_DOWN(arm64_dma32_phys_limit);
@ -236,25 +235,23 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
unsigned long start = memblock_region_memory_base_pfn(reg);
unsigned long end = memblock_region_memory_end_pfn(reg);
if (start >= max)
continue;
#ifdef CONFIG_ZONE_DMA
if (start < max_dma) {
unsigned long dma_end = min_not_zero(end, max_dma);
if (start >= min && start < max_dma) {
unsigned long dma_end = min(end, max_dma);
zhole_size[ZONE_DMA] -= dma_end - start;
start = dma_end;
}
#endif
#ifdef CONFIG_ZONE_DMA32
if (start < max_dma32) {
if (start >= max_dma && start < max_dma32) {
unsigned long dma32_end = min(end, max_dma32);
unsigned long dma32_start = max(start, max_dma);
zhole_size[ZONE_DMA32] -= dma32_end - dma32_start;
zhole_size[ZONE_DMA32] -= dma32_end - start;
start = dma32_end;
}
#endif
if (end > max_dma32) {
if (start >= max_dma32 && start < max) {
unsigned long normal_end = min(end, max);
unsigned long normal_start = max(start, max_dma32);
zhole_size[ZONE_NORMAL] -= normal_end - normal_start;
zhole_size[ZONE_NORMAL] -= normal_end - start;
}
}