ARM: ignore memory below PHYS_OFFSET

commit 571b14375019c3a66ef70d4d4a7083f4238aca30 upstream.

If the kernel is loaded higher in physical memory than normal, and we
calculate PHYS_OFFSET higher than the start of RAM, this leads to
boot problems as we attempt to map part of this RAM into userspace.
Rather than struggle with this, just truncate the mapping.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 31fc16247a8da1d6927e322c50a7e46333ff2957..2a767d262c17fbacbdeeef6088abcc62e32661de 100644 (file)
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -656,6 +656,20 @@ int __init arm_add_memory(phys_addr_t start, phys_addr_t size)
        }
 #endif
 
+       if (aligned_start < PHYS_OFFSET) {
+               if (aligned_start + size <= PHYS_OFFSET) {
+                       pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
+                               aligned_start, aligned_start + size);
+                       return -EINVAL;
+               }
+
+               pr_info("Ignoring memory below PHYS_OFFSET: 0x%08llx-0x%08llx\n",
+                       aligned_start, (u64)PHYS_OFFSET);
+
+               size -= PHYS_OFFSET - aligned_start;
+               aligned_start = PHYS_OFFSET;
+       }
+
        bank->start = aligned_start;
        bank->size = size & ~(phys_addr_t)(PAGE_SIZE - 1);