riscv: Make sure the linear mapping does not use the kernel mapping

For 64-bit kernel, the end of the address space is occupied by the
kernel mapping and currently, the functions to populate the kernel page
tables (i.e. create_p*d_mapping) do not override existing mapping so we
must make sure the linear mapping does not map memory in the kernel mapping
by clipping the memory above the memory limit.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Fixes: c9811e379b21 ("riscv: Add mem kernel parameter support")
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index e4356d6..644a34b 100644 (file)
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -717,6 +717,8 @@ static void __init setup_vm_final(void)
                if (start <= __pa(PAGE_OFFSET) &&
                    __pa(PAGE_OFFSET) < end)
                        start = __pa(PAGE_OFFSET);
+               if (end >= __pa(PAGE_OFFSET) + memory_limit)
+                       end = __pa(PAGE_OFFSET) + memory_limit;
 
                map_size = best_map_size(start, end - start);
                for (pa = start; pa < end; pa += map_size) {