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-rw-r--r--arch/powerpc/mm/book3s64/hash_utils.c9
-rw-r--r--arch/powerpc/mm/mem.c2
2 files changed, 10 insertions, 1 deletions
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 9a5963e07a82..b8ad14bb1170 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -1899,11 +1899,20 @@ void hash__setup_initial_memory_limit(phys_addr_t first_memblock_base,
*
* For guests on platforms before POWER9, we clamp the it limit to 1G
* to avoid some funky things such as RTAS bugs etc...
+ *
+ * On POWER9 we limit to 1TB in case the host erroneously told us that
+ * the RMA was >1TB. Effective address bits 0:23 are treated as zero
+ * (meaning the access is aliased to zero i.e. addr = addr % 1TB)
+ * for virtual real mode addressing and so it doesn't make sense to
+ * have an area larger than 1TB as it can't be addressed.
*/
if (!early_cpu_has_feature(CPU_FTR_HVMODE)) {
ppc64_rma_size = first_memblock_size;
if (!early_cpu_has_feature(CPU_FTR_ARCH_300))
ppc64_rma_size = min_t(u64, ppc64_rma_size, 0x40000000);
+ else
+ ppc64_rma_size = min_t(u64, ppc64_rma_size,
+ 1UL << SID_SHIFT_1T);
/* Finally limit subsequent allocations */
memblock_set_current_limit(ppc64_rma_size);
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 9259337d7374..9191a66b3bc5 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -239,7 +239,7 @@ void __init paging_init(void)
#ifdef CONFIG_ZONE_DMA
max_zone_pfns[ZONE_DMA] = min(max_low_pfn,
- ((1UL << ARCH_ZONE_DMA_BITS) - 1) >> PAGE_SHIFT);
+ 1UL << (ARCH_ZONE_DMA_BITS - PAGE_SHIFT));
#endif
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_HIGHMEM