Merge tag 'for-linus-20170812' of git://git.infradead.org/linux-mtd

[karo-tx-linux.git] / arch / powerpc / mm / pgtable-radix.c

diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 5cc50d47ce3f99f4bf331a4b6a4c4be18c46379e..671a45d86c18dd7e174ffb909084cd0a37fcdaff 100644 (file)
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -25,6 +25,9 @@
 
 #include <trace/events/thp.h>
 
+unsigned int mmu_pid_bits;
+unsigned int mmu_base_pid;
+
 static int native_register_process_table(unsigned long base, unsigned long pg_sz,
                                         unsigned long table_size)
 {
@@ -261,11 +264,34 @@ static void __init radix_init_pgtable(void)
        for_each_memblock(memory, reg)
                WARN_ON(create_physical_mapping(reg->base,
                                                reg->base + reg->size));
+
+       /* Find out how many PID bits are supported */
+       if (cpu_has_feature(CPU_FTR_HVMODE)) {
+               if (!mmu_pid_bits)
+                       mmu_pid_bits = 20;
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+               /*
+                * When KVM is possible, we only use the top half of the
+                * PID space to avoid collisions between host and guest PIDs
+                * which can cause problems due to prefetch when exiting the
+                * guest with AIL=3
+                */
+               mmu_base_pid = 1 << (mmu_pid_bits - 1);
+#else
+               mmu_base_pid = 1;
+#endif
+       } else {
+               /* The guest uses the bottom half of the PID space */
+               if (!mmu_pid_bits)
+                       mmu_pid_bits = 19;
+               mmu_base_pid = 1;
+       }
+
        /*
         * Allocate Partition table and process table for the
         * host.
         */
-       BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 36), "Process table size too large.");
+       BUG_ON(PRTB_SIZE_SHIFT > 36);
        process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
        /*
         * Fill in the process table.
@@ -339,6 +365,12 @@ static int __init radix_dt_scan_page_sizes(unsigned long node,
        if (type == NULL || strcmp(type, "cpu") != 0)
                return 0;
 
+       /* Find MMU PID size */
+       prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
+       if (prop && size == 4)
+               mmu_pid_bits = be32_to_cpup(prop);
+
+       /* Grab page size encodings */
        prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
        if (!prop)
                return 0;