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-rw-r--r--arch/ia64/mm/init.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 65f9958db9f0..1281c609ee98 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -382,13 +382,22 @@ ia64_mmu_init (void *my_cpu_data)
if (impl_va_bits < 51 || impl_va_bits > 61)
panic("CPU has bogus IMPL_VA_MSB value of %lu!\n", impl_va_bits - 1);
+ /*
+ * mapped_space_bits - PAGE_SHIFT is the total number of ptes we need,
+ * which must fit into "vmlpt_bits - pte_bits" slots. Second half of
+ * the test makes sure that our mapped space doesn't overlap the
+ * unimplemented hole in the middle of the region.
+ */
+ if ((mapped_space_bits - PAGE_SHIFT > vmlpt_bits - pte_bits) ||
+ (mapped_space_bits > impl_va_bits - 1))
+ panic("Cannot build a big enough virtual-linear page table"
+ " to cover mapped address space.\n"
+ " Try using a smaller page size.\n");
+
/* place the VMLPT at the end of each page-table mapped region: */
pta = POW2(61) - POW2(vmlpt_bits);
- if (POW2(mapped_space_bits) >= pta)
- panic("mm/init: overlap between virtually mapped linear page table and "
- "mapped kernel space!");
/*
* Set the (virtually mapped linear) page table address. Bit
* 8 selects between the short and long format, bits 2-7 the