From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
Linux doesn't own the memory immediately after the kernel image. On Octeon
bootloader places a shared structure right close after the kernel _end,
refer to "struct cvmx_bootinfo *octeon_bootinfo" in cavium-octeon/setup.c.
If check_kernel_sections_mem() rounds the PFNs up, first memblock_alloc()
inside early_init_dt_alloc_memory_arch() <= device_tree_init() returns
memory block overlapping with the above octeon_bootinfo structure, which
is being overwritten afterwards.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map")
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
---
arch/mips/kernel/setup.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 0d42532..f6cf2f6 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -504,6 +504,12 @@ static void __init check_kernel_sections_mem(void)
if (!memblock_is_region_memory(start, size)) {
pr_info("Kernel sections are not in the memory maps\n");
memblock_add(start, size);
+ /*
+ * Octeon bootloader places shared data structure right after
+ * the kernel => make sure it will not be corrupted.
+ */
+ memblock_reserve(__pa_symbol(&_end),
+ start + size - __pa_symbol(&_end));
}
}
--
2.10.2
