[POWERPC] Distinguish POWER6 partition modes and tell userspace

This adds code to look at the properties firmware puts in the device
tree to determine what compatibility mode the partition is in on
POWER6 machines, and set the ELF aux vector AT_HWCAP and AT_PLATFORM
entries appropriately.

Specifically, we look at the cpu-version property in the cpu node(s).
If that contains a "logical" PVR value (of the form 0x0f00000x), we
call identify_cpu again with this PVR value.  A value of 0x0f000001
indicates the partition is in POWER5+ compatibility mode, and a value
of 0x0f000002 indicates "POWER6 architected" mode, with various
extensions disabled.  We also look for various other properties:
ibm,dfp, ibm,purr and ibm,spurr.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 76 insertions, 34 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 16d29d16b96f..c18dbe77fdc2 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -538,35 +538,31 @@ static struct ibm_pa_feature {
 	{CPU_FTR_REAL_LE, PPC_FEATURE_TRUE_LE, 5, 0, 0},
 };
 
-static void __init check_cpu_pa_features(unsigned long node)
+static void __init scan_features(unsigned long node, unsigned char *ftrs,
+				 unsigned long tablelen,
+				 struct ibm_pa_feature *fp,
+				 unsigned long ft_size)
 {
-	unsigned char *pa_ftrs;
-	unsigned long len, tablelen, i, bit;
-
-	pa_ftrs = of_get_flat_dt_prop(node, "ibm,pa-features", &tablelen);
-	if (pa_ftrs == NULL)
-		return;
+	unsigned long i, len, bit;
 
 	/* find descriptor with type == 0 */
 	for (;;) {
 		if (tablelen < 3)
 			return;
-		len = 2 + pa_ftrs[0];
+		len = 2 + ftrs[0];
 		if (tablelen < len)
 			return;		/* descriptor 0 not found */
-		if (pa_ftrs[1] == 0)
+		if (ftrs[1] == 0)
 			break;
 		tablelen -= len;
-		pa_ftrs += len;
+		ftrs += len;
 	}
 
 	/* loop over bits we know about */
-	for (i = 0; i < ARRAY_SIZE(ibm_pa_features); ++i) {
-		struct ibm_pa_feature *fp = &ibm_pa_features[i];
-
-		if (fp->pabyte >= pa_ftrs[0])
+	for (i = 0; i < ft_size; ++i, ++fp) {
+		if (fp->pabyte >= ftrs[0])
 			continue;
-		bit = (pa_ftrs[2 + fp->pabyte] >> (7 - fp->pabit)) & 1;
+		bit = (ftrs[2 + fp->pabyte] >> (7 - fp->pabit)) & 1;
 		if (bit ^ fp->invert) {
 			cur_cpu_spec->cpu_features |= fp->cpu_features;
 			cur_cpu_spec->cpu_user_features |= fp->cpu_user_ftrs;
@@ -577,16 +573,59 @@ static void __init check_cpu_pa_features(unsigned long node)
 	}
 }
 
+static void __init check_cpu_pa_features(unsigned long node)
+{
+	unsigned char *pa_ftrs;
+	unsigned long tablelen;
+
+	pa_ftrs = of_get_flat_dt_prop(node, "ibm,pa-features", &tablelen);
+	if (pa_ftrs == NULL)
+		return;
+
+	scan_features(node, pa_ftrs, tablelen,
+		      ibm_pa_features, ARRAY_SIZE(ibm_pa_features));
+}
+
+static struct feature_property {
+	const char *name;
+	u32 min_value;
+	unsigned long cpu_feature;
+	unsigned long cpu_user_ftr;
+} feature_properties[] __initdata = {
+#ifdef CONFIG_ALTIVEC
+	{"altivec", 0, CPU_FTR_ALTIVEC, PPC_FEATURE_HAS_ALTIVEC},
+	{"ibm,vmx", 1, CPU_FTR_ALTIVEC, PPC_FEATURE_HAS_ALTIVEC},
+#endif /* CONFIG_ALTIVEC */
+#ifdef CONFIG_PPC64
+	{"ibm,dfp", 1, 0, PPC_FEATURE_HAS_DFP},
+	{"ibm,purr", 1, CPU_FTR_PURR, 0},
+	{"ibm,spurr", 1, CPU_FTR_SPURR, 0},
+#endif /* CONFIG_PPC64 */
+};
+
+static void __init check_cpu_feature_properties(unsigned long node)
+{
+	unsigned long i;
+	struct feature_property *fp = feature_properties;
+	const u32 *prop;
+
+	for (i = 0; i < ARRAY_SIZE(feature_properties); ++i, ++fp) {
+		prop = of_get_flat_dt_prop(node, fp->name, NULL);
+		if (prop && *prop >= fp->min_value) {
+			cur_cpu_spec->cpu_features |= fp->cpu_feature;
+			cur_cpu_spec->cpu_user_features |= fp->cpu_user_ftr;
+		}
+	}
+}
+
 static int __init early_init_dt_scan_cpus(unsigned long node,
 					  const char *uname, int depth,
 					  void *data)
 {
 	static int logical_cpuid = 0;
 	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
-#ifdef CONFIG_ALTIVEC
-	u32 *prop;
-#endif
-	u32 *intserv;
+	const u32 *prop;
+	const u32 *intserv;
 	int i, nthreads;
 	unsigned long len;
 	int found = 0;
@@ -643,24 +682,27 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 			intserv[i]);
 		boot_cpuid = logical_cpuid;
 		set_hard_smp_processor_id(boot_cpuid, intserv[i]);
-	}
 
-#ifdef CONFIG_ALTIVEC
-	/* Check if we have a VMX and eventually update CPU features */
-	prop = (u32 *)of_get_flat_dt_prop(node, "ibm,vmx", NULL);
-	if (prop && (*prop) > 0) {
-		cur_cpu_spec->cpu_features |= CPU_FTR_ALTIVEC;
-		cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_ALTIVEC;
-	}
-
-	/* Same goes for Apple's "altivec" property */
-	prop = (u32 *)of_get_flat_dt_prop(node, "altivec", NULL);
-	if (prop) {
-		cur_cpu_spec->cpu_features |= CPU_FTR_ALTIVEC;
-		cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_ALTIVEC;
+		/*
+		 * PAPR defines "logical" PVR values for cpus that
+		 * meet various levels of the architecture:
+		 * 0x0f000001	Architecture version 2.04
+		 * 0x0f000002	Architecture version 2.05
+		 * If the cpu-version property in the cpu node contains
+		 * such a value, we call identify_cpu again with the
+		 * logical PVR value in order to use the cpu feature
+		 * bits appropriate for the architecture level.
+		 *
+		 * A POWER6 partition in "POWER6 architected" mode
+		 * uses the 0x0f000002 PVR value; in POWER5+ mode
+		 * it uses 0x0f000001.
+		 */
+		prop = of_get_flat_dt_prop(node, "cpu-version", NULL);
+		if (prop && (*prop & 0xff000000) == 0x0f000000)
+			identify_cpu(0, *prop);
 	}
-#endif /* CONFIG_ALTIVEC */
 
+	check_cpu_feature_properties(node);
 	check_cpu_pa_features(node);
 
 #ifdef CONFIG_PPC_PSERIES