queue-4.19/mips-make-sure-dt-memory-regions-are-valid.patch

   1 From 8e6fcbe5380fd4cf83249c060bf0ef93f2a7ff05 Mon Sep 17 00:00:00 2001
   2 From: Serge Semin <fancer.lancer@gmail.com>
   3 Date: Fri, 3 May 2019 20:50:40 +0300
   4 Subject: mips: Make sure dt memory regions are valid
   5
   6 [ Upstream commit 93fa5b280761a4dbb14c5330f260380385ab2b49 ]
   7
   8 There are situations when memory regions coming from dts may be
   9 too big for the platform physical address space. This especially
  10 concerns XPA-capable systems. Bootloader may determine more than 4GB
  11 memory available and pass it to the kernel over dts memory node, while
  12 kernel is built without XPA/64BIT support. In this case the region
  13 may either simply be truncated by add_memory_region() method
  14 or by u64->phys_addr_t type casting. But in worst case the method
  15 can even drop the memory region if it exceeds PHYS_ADDR_MAX size.
  16 So lets make sure the retrieved from dts memory regions are valid,
  17 and if some of them aren't, just manually truncate them with a warning
  18 printed out.
  19
  20 Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
  21 Signed-off-by: Paul Burton <paul.burton@mips.com>
  22 Cc: Ralf Baechle <ralf@linux-mips.org>
  23 Cc: James Hogan <jhogan@kernel.org>
  24 Cc: Mike Rapoport <rppt@linux.ibm.com>
  25 Cc: Andrew Morton <akpm@linux-foundation.org>
  26 Cc: Michal Hocko <mhocko@suse.com>
  27 Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  28 Cc: Thomas Bogendoerfer <tbogendoerfer@suse.de>
  29 Cc: Huacai Chen <chenhc@lemote.com>
  30 Cc: Stefan Agner <stefan@agner.ch>
  31 Cc: Stephen Rothwell <sfr@canb.auug.org.au>
  32 Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
  33 Cc: Juergen Gross <jgross@suse.com>
  34 Cc: Serge Semin <Sergey.Semin@t-platforms.ru>
  35 Cc: linux-mips@vger.kernel.org
  36 Cc: linux-kernel@vger.kernel.org
  37 Signed-off-by: Sasha Levin <sashal@kernel.org>
  38 ---
  39  arch/mips/kernel/prom.c | 14 +++++++++++++-
  40  1 file changed, 13 insertions(+), 1 deletion(-)
  41
  42 diff --git a/arch/mips/kernel/prom.c b/arch/mips/kernel/prom.c
  43 index 89950b7bf536..bdaf3536241a 100644
  44 --- a/arch/mips/kernel/prom.c
  45 +++ b/arch/mips/kernel/prom.c
  46 @@ -41,7 +41,19 @@ char *mips_get_machine_name(void)
  47  #ifdef CONFIG_USE_OF
  48  void __init early_init_dt_add_memory_arch(u64 base, u64 size)
  49  {
  50 -       return add_memory_region(base, size, BOOT_MEM_RAM);
  51 +       if (base >= PHYS_ADDR_MAX) {
  52 +               pr_warn("Trying to add an invalid memory region, skipped\n");
  53 +               return;
  54 +       }
  55 +
  56 +       /* Truncate the passed memory region instead of type casting */
  57 +       if (base + size - 1 >= PHYS_ADDR_MAX || base + size < base) {
  58 +               pr_warn("Truncate memory region %llx @ %llx to size %llx\n",
  59 +                       size, base, PHYS_ADDR_MAX - base);
  60 +               size = PHYS_ADDR_MAX - base;
  61 +       }
  62 +
  63 +       add_memory_region(base, size, BOOT_MEM_RAM);
  64  }
  65
  66  int __init early_init_dt_reserve_memory_arch(phys_addr_t base,
  67 --
  68 2.20.1
  69