git.openwrt.org Git - openwrt/staging/mans0n.git/blob

   1 From cd2d09e995bc72711b48b5c271b72e3ea3e99cdf Mon Sep 17 00:00:00 2001
   2 From: Will Deacon <will@kernel.org>
   3 Date: Tue, 3 Dec 2019 12:10:13 +0000
   4 Subject: [PATCH] arm64: mm: Fix initialisation of DMA zones on
   5  non-NUMA systems
   6
   7 commit 93b90414c33f59b7960bc8d607da0ce83377e021 upstream.
   8
   9 John reports that the recently merged commit 1a8e1cef7603 ("arm64: use
  10 both ZONE_DMA and ZONE_DMA32") breaks the boot on his DB845C board:
  11
  12   | Booting Linux on physical CPU 0x0000000000 [0x517f803c]
  13   | Linux version 5.4.0-mainline-10675-g957a03b9e38f
  14   | Machine model: Thundercomm Dragonboard 845c
  15   | [...]
  16   | Built 1 zonelists, mobility grouping on.  Total pages: -188245
  17   | Kernel command line: earlycon
  18   | firmware_class.path=/vendor/firmware/ androidboot.hardware=db845c
  19   | init=/init androidboot.boot_devices=soc/1d84000.ufshc
  20   | printk.devkmsg=on buildvariant=userdebug root=/dev/sda2
  21   | androidboot.bootdevice=1d84000.ufshc androidboot.serialno=c4e1189c
  22   | androidboot.baseband=sda
  23   | msm_drm.dsi_display0=dsi_lt9611_1080_video_display:
  24   | androidboot.slot_suffix=_a skip_initramfs rootwait ro init=/init
  25   |
  26   | <hangs indefinitely here>
  27
  28 This is because, when CONFIG_NUMA=n, zone_sizes_init() fails to handle
  29 memblocks that fall entirely within the ZONE_DMA region and erroneously ends up
  30 trying to add a negatively-sized region into the following ZONE_DMA32, which is
  31 later interpreted as a large unsigned region by the core MM code.
  32
  33 Rework the non-NUMA implementation of zone_sizes_init() so that the start
  34 address of the memblock being processed is adjusted according to the end of the
  35 previous zone, which is then range-checked before updating the hole information
  36 of subsequent zones.
  37
  38 Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
  39 Cc: Christoph Hellwig <hch@lst.de>
  40 Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
  41 Link: https://lore.kernel.org/lkml/CALAqxLVVcsmFrDKLRGRq7GewcW405yTOxG=KR3csVzQ6bXutkA@mail.gmail.com
  42 Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
  43 Reported-by: John Stultz <john.stultz@linaro.org>
  44 Tested-by: John Stultz <john.stultz@linaro.org>
  45 Signed-off-by: Will Deacon <will@kernel.org>
  46 Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
  47 ---
  48  arch/arm64/mm/init.c | 25 +++++++++++--------------
  49  1 file changed, 11 insertions(+), 14 deletions(-)
  50
  51 --- a/arch/arm64/mm/init.c
  52 +++ b/arch/arm64/mm/init.c
  53 @@ -208,15 +208,14 @@ static void __init zone_sizes_init(unsig
  54  {
  55         struct memblock_region *reg;
  56         unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
  57 -       unsigned long max_dma32 = min;
  58 -       unsigned long max_dma = min;
  59 +       unsigned long __maybe_unused max_dma, max_dma32;
  60
  61         memset(zone_size, 0, sizeof(zone_size));
  62
  63 +       max_dma = max_dma32 = min;
  64  #ifdef CONFIG_ZONE_DMA
  65 -       max_dma = PFN_DOWN(arm64_dma_phys_limit);
  66 +       max_dma = max_dma32 = PFN_DOWN(arm64_dma_phys_limit);
  67         zone_size[ZONE_DMA] = max_dma - min;
  68 -       max_dma32 = max_dma;
  69  #endif
  70  #ifdef CONFIG_ZONE_DMA32
  71         max_dma32 = PFN_DOWN(arm64_dma32_phys_limit);
  72 @@ -230,25 +229,23 @@ static void __init zone_sizes_init(unsig
  73                 unsigned long start = memblock_region_memory_base_pfn(reg);
  74                 unsigned long end = memblock_region_memory_end_pfn(reg);
  75
  76 -               if (start >= max)
  77 -                       continue;
  78  #ifdef CONFIG_ZONE_DMA
  79 -               if (start < max_dma) {
  80 -                       unsigned long dma_end = min_not_zero(end, max_dma);
  81 +               if (start >= min && start < max_dma) {
  82 +                       unsigned long dma_end = min(end, max_dma);
  83                         zhole_size[ZONE_DMA] -= dma_end - start;
  84 +                       start = dma_end;
  85                 }
  86  #endif
  87  #ifdef CONFIG_ZONE_DMA32
  88 -               if (start < max_dma32) {
  89 +               if (start >= max_dma && start < max_dma32) {
  90                         unsigned long dma32_end = min(end, max_dma32);
  91 -                       unsigned long dma32_start = max(start, max_dma);
  92 -                       zhole_size[ZONE_DMA32] -= dma32_end - dma32_start;
  93 +                       zhole_size[ZONE_DMA32] -= dma32_end - start;
  94 +                       start = dma32_end;
  95                 }
  96  #endif
  97 -               if (end > max_dma32) {
  98 +               if (start >= max_dma32 && start < max) {
  99                         unsigned long normal_end = min(end, max);
 100 -                       unsigned long normal_start = max(start, max_dma32);
 101 -                       zhole_size[ZONE_NORMAL] -= normal_end - normal_start;
 102 +                       zhole_size[ZONE_NORMAL] -= normal_end - start;
 103                 }
 104         }
 105