Merge branch 'next' into for-linus

Prepare input updates for 4.14 merge window.

1 files changed, 48 insertions, 10 deletions

diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index fcc7588a96d6..4c7656dc4e04 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -8,6 +8,7 @@
 #include <linux/export.h>
 #include <linux/init.h>
 #include <linux/jump_label.h>
+#include <linux/libfdt.h>
 #include <linux/memblock.h>
 #include <linux/printk.h>
 #include <linux/sched.h>
@@ -642,7 +643,6 @@ static struct dt_cpu_feature_match __initdata
         {"processor-control-facility", feat_enable_dbell, CPU_FTR_DBELL},
         {"processor-control-facility-v3", feat_enable_dbell, CPU_FTR_DBELL},
         {"processor-utilization-of-resources-register", feat_enable_purr, 0},
-        {"subcore", feat_enable, CPU_FTR_SUBCORE},
         {"no-execute", feat_enable, 0},
         {"strong-access-ordering", feat_enable, CPU_FTR_SAO},
         {"cache-inhibited-large-page", feat_enable_large_ci, 0},
@@ -671,12 +671,24 @@ static struct dt_cpu_feature_match __initdata
         {"wait-v3", feat_enable, 0},
 };
 
-/* XXX: how to configure this? Default + boot time? */
-#ifdef CONFIG_PPC_CPUFEATURES_ENABLE_UNKNOWN
-#define CPU_FEATURE_ENABLE_UNKNOWN 1
-#else
-#define CPU_FEATURE_ENABLE_UNKNOWN 0
-#endif
+static bool __initdata using_dt_cpu_ftrs;
+static bool __initdata enable_unknown = true;
+
+static int __init dt_cpu_ftrs_parse(char *str)
+{
+        if (!str)
+                return 0;
+
+        if (!strcmp(str, "off"))
+                using_dt_cpu_ftrs = false;
+        else if (!strcmp(str, "known"))
+                enable_unknown = false;
+        else
+                return 1;
+
+        return 0;
+}
+early_param("dt_cpu_ftrs", dt_cpu_ftrs_parse);
 
 static void __init cpufeatures_setup_start(u32 isa)
 {
@@ -707,7 +719,7 @@ static bool __init cpufeatures_process_feature(struct dt_cpu_feature *f)
                 }
         }
 
-        if (!known && CPU_FEATURE_ENABLE_UNKNOWN) {
+        if (!known && enable_unknown) {
                 if (!feat_try_enable_unknown(f)) {
                         pr_info("not enabling: %s (unknown and unsupported by kernel)\n",
                                 f->name);
@@ -756,6 +768,26 @@ static void __init cpufeatures_setup_finished(void)
                 cur_cpu_spec->cpu_features, cur_cpu_spec->mmu_features);
 }
 
+static int __init disabled_on_cmdline(void)
+{
+        unsigned long root, chosen;
+        const char *p;
+
+        root = of_get_flat_dt_root();
+        chosen = of_get_flat_dt_subnode_by_name(root, "chosen");
+        if (chosen == -FDT_ERR_NOTFOUND)
+                return false;
+
+        p = of_get_flat_dt_prop(chosen, "bootargs", NULL);
+        if (!p)
+                return false;
+
+        if (strstr(p, "dt_cpu_ftrs=off"))
+                return true;
+
+        return false;
+}
+
 static int __init fdt_find_cpu_features(unsigned long node, const char *uname,
                                         int depth, void *data)
 {
@@ -766,8 +798,6 @@ static int __init fdt_find_cpu_features(unsigned long node, const char *uname,
         return 0;
 }
 
-static bool __initdata using_dt_cpu_ftrs = false;
-
 bool __init dt_cpu_ftrs_in_use(void)
 {
         return using_dt_cpu_ftrs;
@@ -775,6 +805,8 @@ bool __init dt_cpu_ftrs_in_use(void)
 
 bool __init dt_cpu_ftrs_init(void *fdt)
 {
+        using_dt_cpu_ftrs = false;
+
         /* Setup and verify the FDT, if it fails we just bail */
         if (!early_init_dt_verify(fdt))
                 return false;
@@ -782,6 +814,9 @@ bool __init dt_cpu_ftrs_init(void *fdt)
         if (!of_scan_flat_dt(fdt_find_cpu_features, NULL))
                 return false;
 
+        if (disabled_on_cmdline())
+                return false;
+
         cpufeatures_setup_cpu();
 
         using_dt_cpu_ftrs = true;
@@ -1027,5 +1062,8 @@ static int __init dt_cpu_ftrs_scan_callback(unsigned long node, const char
 
 void __init dt_cpu_ftrs_scan(void)
 {
+        if (!using_dt_cpu_ftrs)
+                return;
+
         of_scan_flat_dt(dt_cpu_ftrs_scan_callback, NULL);
 }