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Diffstat (limited to 'arch/powerpc/mm/init_64.c')
-rw-r--r--arch/powerpc/mm/init_64.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 8e1588021d1c..6aa3b76aa0d6 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -42,6 +42,8 @@
#include <linux/memblock.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
@@ -344,6 +346,30 @@ static int __init parse_disable_radix(char *p)
}
early_param("disable_radix", parse_disable_radix);
+/*
+ * If we're running under a hypervisor, we need to check the contents of
+ * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do
+ * radix. If not, we clear the radix feature bit so we fall back to hash.
+ */
+static void early_check_vec5(void)
+{
+ unsigned long root, chosen;
+ int size;
+ const u8 *vec5;
+
+ root = of_get_flat_dt_root();
+ chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
+ if (chosen == -FDT_ERR_NOTFOUND)
+ return;
+ vec5 = of_get_flat_dt_prop(chosen, "ibm,architecture-vec-5", &size);
+ if (!vec5)
+ return;
+ if (size <= OV5_INDX(OV5_MMU_RADIX_300) ||
+ !(vec5[OV5_INDX(OV5_MMU_RADIX_300)] & OV5_FEAT(OV5_MMU_RADIX_300)))
+ /* Hypervisor doesn't support radix */
+ cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
+}
+
void __init mmu_early_init_devtree(void)
{
/* Disable radix mode based on kernel command line. */
@@ -351,6 +377,15 @@ void __init mmu_early_init_devtree(void)
if (disable_radix || !(mfmsr() & MSR_HV))
cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
+ /*
+ * Check /chosen/ibm,architecture-vec-5 if running as a guest.
+ * When running bare-metal, we can use radix if we like
+ * even though the ibm,architecture-vec-5 property created by
+ * skiboot doesn't have the necessary bits set.
+ */
+ if (early_radix_enabled() && !(mfmsr() & MSR_HV))
+ early_check_vec5();
+
if (early_radix_enabled())
radix__early_init_devtree();
else