1 files changed, 113 insertions, 7 deletions

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index a3944540fe0d..1c1b44ec7642 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -168,6 +168,14 @@ static unsigned long __initdata prom_tce_alloc_start;
 static unsigned long __initdata prom_tce_alloc_end;
 #endif
 
+static bool __initdata prom_radix_disable;
+
+struct platform_support {
+        bool hash_mmu;
+        bool radix_mmu;
+        bool radix_gtse;
+};
+
 /* Platforms codes are now obsolete in the kernel. Now only used within this
  * file and ultimately gone too. Feel free to change them if you need, they
  * are not shared with anything outside of this file anymore
@@ -626,6 +634,12 @@ static void __init early_cmdline_parse(void)
                 prom_memory_limit = ALIGN(prom_memory_limit, 0x1000000);
 #endif
         }
+
+        opt = strstr(prom_cmd_line, "disable_radix");
+        if (opt) {
+                prom_debug("Radix disabled from cmdline\n");
+                prom_radix_disable = true;
+        }
 }
 
 #if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
@@ -695,6 +709,8 @@ struct option_vector5 {
         u8 byte22;
         u8 intarch;
         u8 mmu;
+        u8 hash_ext;
+        u8 radix_ext;
 } __packed;
 
 struct option_vector6 {
@@ -850,8 +866,9 @@ struct ibm_arch_vec __cacheline_aligned ibm_architecture_vec = {
                 .reserved3 = 0,
                 .subprocessors = 1,
                 .intarch = 0,
-                .mmu = OV5_FEAT(OV5_MMU_RADIX_300) | OV5_FEAT(OV5_MMU_HASH_300) |
-                        OV5_FEAT(OV5_MMU_PROC_TBL) | OV5_FEAT(OV5_MMU_GTSE),
+                .mmu = 0,
+                .hash_ext = 0,
+                .radix_ext = 0,
         },
 
         /* option vector 6: IBM PAPR hints */
@@ -990,6 +1007,92 @@ static int __init prom_count_smt_threads(void)
 
 }
 
+static void __init prom_parse_mmu_model(u8 val,
+                                        struct platform_support *support)
+{
+        switch (val) {
+        case OV5_FEAT(OV5_MMU_DYNAMIC):
+        case OV5_FEAT(OV5_MMU_EITHER): /* Either Available */
+                prom_debug("MMU - either supported\n");
+                support->radix_mmu = !prom_radix_disable;
+                support->hash_mmu = true;
+                break;
+        case OV5_FEAT(OV5_MMU_RADIX): /* Only Radix */
+                prom_debug("MMU - radix only\n");
+                if (prom_radix_disable) {
+                        /*
+                         * If we __have__ to do radix, we're better off ignoring
+                         * the command line rather than not booting.
+                         */
+                        prom_printf("WARNING: Ignoring cmdline option disable_radix\n");
+                }
+                support->radix_mmu = true;
+                break;
+        case OV5_FEAT(OV5_MMU_HASH):
+                prom_debug("MMU - hash only\n");
+                support->hash_mmu = true;
+                break;
+        default:
+                prom_debug("Unknown mmu support option: 0x%x\n", val);
+                break;
+        }
+}
+
+static void __init prom_parse_platform_support(u8 index, u8 val,
+                                               struct platform_support *support)
+{
+        switch (index) {
+        case OV5_INDX(OV5_MMU_SUPPORT): /* MMU Model */
+                prom_parse_mmu_model(val & OV5_FEAT(OV5_MMU_SUPPORT), support);
+                break;
+        case OV5_INDX(OV5_RADIX_GTSE): /* Radix Extensions */
+                if (val & OV5_FEAT(OV5_RADIX_GTSE)) {
+                        prom_debug("Radix - GTSE supported\n");
+                        support->radix_gtse = true;
+                }
+                break;
+        }
+}
+
+static void __init prom_check_platform_support(void)
+{
+        struct platform_support supported = {
+                .hash_mmu = false,
+                .radix_mmu = false,
+                .radix_gtse = false
+        };
+        int prop_len = prom_getproplen(prom.chosen,
+                                       "ibm,arch-vec-5-platform-support");
+        if (prop_len > 1) {
+                int i;
+                u8 vec[prop_len];
+                prom_debug("Found ibm,arch-vec-5-platform-support, len: %d\n",
+                           prop_len);
+                prom_getprop(prom.chosen, "ibm,arch-vec-5-platform-support",
+                             &vec, sizeof(vec));
+                for (i = 0; i < prop_len; i += 2) {
+                        prom_debug("%d: index = 0x%x val = 0x%x\n", i / 2
+                                                                  , vec[i]
+                                                                  , vec[i + 1]);
+                        prom_parse_platform_support(vec[i], vec[i + 1],
+                                                    &supported);
+                }
+        }
+
+        if (supported.radix_mmu && supported.radix_gtse) {
+                /* Radix preferred - but we require GTSE for now */
+                prom_debug("Asking for radix with GTSE\n");
+                ibm_architecture_vec.vec5.mmu = OV5_FEAT(OV5_MMU_RADIX);
+                ibm_architecture_vec.vec5.radix_ext = OV5_FEAT(OV5_RADIX_GTSE);
+        } else if (supported.hash_mmu) {
+                /* Default to hash mmu (if we can) */
+                prom_debug("Asking for hash\n");
+                ibm_architecture_vec.vec5.mmu = OV5_FEAT(OV5_MMU_HASH);
+        } else {
+                /* We're probably on a legacy hypervisor */
+                prom_debug("Assuming legacy hash support\n");
+        }
+}
 
 static void __init prom_send_capabilities(void)
 {
@@ -997,6 +1100,9 @@ static void __init prom_send_capabilities(void)
         prom_arg_t ret;
         u32 cores;
 
+        /* Check ibm,arch-vec-5-platform-support and fixup vec5 if required */
+        prom_check_platform_support();
+
         root = call_prom("open", 1, 1, ADDR("/"));
         if (root != 0) {
                 /* We need to tell the FW about the number of cores we support.
@@ -2993,6 +3099,11 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
          */
         prom_check_initrd(r3, r4);
 
+        /*
+         * Do early parsing of command line
+         */
+        early_cmdline_parse();
+
 #if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
         /*
          * On pSeries, inform the firmware about our capabilities
@@ -3009,11 +3120,6 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
                 copy_and_flush(0, kbase, 0x100, 0);
 
         /*
-         * Do early parsing of command line
-         */
-        early_cmdline_parse();
-
-        /*
          * Initialize memory management within prom_init
          */
         prom_init_mem();