If the size of DRAM is not an exact power of two, we may not have
covered DRAM in its entirety with large 16 and 4 MiB pages. If that
is the case, we can get non-recoverable page faults when doing the
final PTE mappings for the non-large page PTEs.
Consequently, we restrict the top end of DRAM currently allocable
by updating '__initial_memory_limit_addr' so that calls to the LMB to
allocate PTEs for "tail" coverage with normal-sized pages (or other
reasons) do not attempt to allocate outside the allowed range.
Signed-off-by: Grant Erickson <gerickson@nuovations.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
unsigned long __init mmu_mapin_ram(void)
{
- unsigned long v, s;
+ unsigned long v, s, mapped;
phys_addr_t p;
v = KERNELBASE;
s -= LARGE_PAGE_SIZE_4M;
}
- return total_lowmem - s;
+ mapped = total_lowmem - s;
+
+ /* If the size of RAM is not an exact power of two, we may not
+ * have covered RAM in its entirety with 16 and 4 MiB
+ * pages. Consequently, restrict the top end of RAM currently
+ * allocable so that calls to the LMB to allocate PTEs for "tail"
+ * coverage with normal-sized pages (or other reasons) do not
+ * attempt to allocate outside the allowed range.
+ */
+
+ __initial_memory_limit_addr = memstart_addr + mapped;
+
+ return mapped;
}