powerpc/mm: Correct process and partition table max size

commit 555c16328ae6d75a90e234eac9b51998d68f185b upstream.

Version 3.00 of the ISA states that the PATS (partition table size) field
of the PTCR (partition table control register) and the PRTS (process table
size) field of the partition table entry must both be less than or equal
to 24. However the actual size of the partition and process tables is equal
to 2 to the power of 12 plus the PATS and PRTS fields, respectively. This
means that the max allowable size of each of these tables is 2^36 or 64GB
for both.

Thus when checking the size shift for each we should be checking for values
of greater than 36 instead of the current check for shifts larger than 24
and 23.

Fixes: 2bfd65e45e877fb5704730244da67c748d28a1b8
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 688b54517655f1ef787023f18f3cacdcbd62ba3b..ebb7f46f05324c2e8133fbefaf0860ee341e8b39 100644 (file)
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -159,7 +159,7 @@ redo:
         * Allocate Partition table and process table for the
         * host.
         */
-       BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 23), "Process table size too large.");
+       BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 36), "Process table size too large.");
        process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
        /*
         * Fill in the process table.
@@ -181,7 +181,7 @@ static void __init radix_init_partition_table(void)
 
        rts_field = radix__get_tree_size();
 
-       BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 24), "Partition table size too large.");
+       BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 36), "Partition table size too large.");
        partition_tb = early_alloc_pgtable(1UL << PATB_SIZE_SHIFT);
        partition_tb->patb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) |
                                          RADIX_PGD_INDEX_SIZE | PATB_HR);