diff options
Diffstat (limited to 'arch/powerpc/mm/init_64.c')
| -rw-r--r-- | arch/powerpc/mm/init_64.c | 35 |
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 |