target/linux/mpc85xx/patches-6.1/150-arch-powerpc-simpleboot-prevent-overwrite-of-CPU1-sp.patch

   1 From 5f856ccc34df25060d36a5a81b7b45b574d86e35 Mon Sep 17 00:00:00 2001
   2 From: David Bauer <mail@david-bauer.net>
   3 Date: Sun, 3 Dec 2023 20:09:24 +0100
   4 Subject: [PATCH] arch: powerpc: simpleboot: prevent overwrite of CPU1
   5  spin-table
   6
   7 Don't overwrite the spin-table of additional CPU cores with loader-heap.
   8
   9 U-Boot places the spin-table for CPU1 on P1020 SoCs in the top 1MB of
  10 system-memory. Instead of parsing reserved-memory (which would be
  11 considerable more work), reduce the available system-memory for the
  12 loader by 1MB.
  13
  14 This prevents the loader from overwriting the spin-table of
  15 additional CPU cores on these platforms.
  16
  17 Linux itself needs to be made aware by this using reserved-memory
  18 definitions.
  19
  20 This patch is required for using CPU1 on the Extreme Networks
  21 WS-AP3825i.
  22
  23 Signed-off-by: David Bauer <mail@david-bauer.net>
  24 ---
  25  arch/powerpc/boot/simpleboot.c | 5 +++++
  26  1 file changed, 5 insertions(+)
  27
  28 --- a/arch/powerpc/boot/simpleboot.c
  29 +++ b/arch/powerpc/boot/simpleboot.c
  30 @@ -65,6 +65,11 @@ void platform_init(unsigned long r3, uns
  31         if (sizeof(void *) == 4 && memsize64 >= 0x100000000ULL)
  32                 memsize64 = 0xffffffff;
  33
  34 +       /* Reserve upper 1 MB of memory for CPU1 spin-table */
  35 +       if (memsize64 > 0x100000) {
  36 +               memsize64 = memsize64 - 0x100000;
  37 +       }
  38 +
  39         /* finally, setup the timebase */
  40         node = fdt_node_offset_by_prop_value(_dtb_start, -1, "device_type",
  41                                              "cpu", sizeof("cpu"));