[PATCH] ppc64: Add smt_snooze_delay cpu sysfs attribute

From: Anton Blanchard <anton@samba.org>

Add smt_snooze_delay cpu sysfs attribute

arch/ppc64/kernel/idle.c

@@ -161,13 +161,14 @@ int default_idle(void)
 
 #ifdef CONFIG_PPC_PSERIES
 
-DECLARE_PER_CPU(smt_snooze_delay);
+DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
 
 int dedicated_idle(void)
 {
 	long oldval;
 	struct paca_struct *lpaca = get_paca(), *ppaca;
 	unsigned long start_snooze;
+	unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);
 
 	ppaca = &paca[smp_processor_id() ^ 1];
 
@@ -180,14 +181,14 @@ int dedicated_idle(void)
 		if (!oldval) {
 			set_thread_flag(TIF_POLLING_NRFLAG);
 			start_snooze = __get_tb() +
-				naca->smt_snooze_delay*tb_ticks_per_usec;
+				*smt_snooze_delay * tb_ticks_per_usec;
 			while (!need_resched()) {
 				/* need_resched could be 1 or 0 at this 
 				 * point.  If it is 0, set it to 0, so
 				 * an IPI/Prod is sent.  If it is 1, keep
 				 * it that way & schedule work.
 				 */
-				if (naca->smt_snooze_delay == 0 ||
+				if (*smt_snooze_delay == 0 ||
 				    __get_tb() < start_snooze) {
 					HMT_low(); /* Low thread priority */
 					continue;

arch/ppc64/kernel/prom.c

@@ -1254,7 +1254,6 @@ smt_setup(void)
 {
 	char *p, *q;
 	char my_smt_enabled = SMT_DYNAMIC;
-	unsigned long my_smt_snooze_delay; 
 	ihandle prom_options = NULL;
 	char option[9];
 	unsigned long offset = reloc_offset();
@@ -1301,51 +1300,6 @@ smt_setup(void)
 	if (!found )
 		my_smt_enabled = SMT_DYNAMIC; /* default to on */
 
-	found = 0;
-	if (my_smt_enabled) {
-		if (strstr(RELOC(cmd_line), RELOC("smt-snooze-delay="))) {
-			for (q = RELOC(cmd_line); (p = strstr(q, RELOC("smt-snooze-delay="))) != 0; ) {
-				q = p + 17;
-				if (p > RELOC(cmd_line) && p[-1] != ' ')
-					continue;
-				found = 1;
-				/* Don't use simple_strtoul() because _ctype & others aren't RELOC'd */
-				my_smt_snooze_delay = 0;
-				while (*q >= '0' && *q <= '9') {
-					my_smt_snooze_delay = my_smt_snooze_delay * 10 + *q - '0';
-					q++;
-				}
-			}
-		}
-
-		if (!found) {
-			prom_options = (ihandle)call_prom(RELOC("finddevice"), 1, 1, RELOC("/options"));
-			if (prom_options != (ihandle) -1) {
-				call_prom(RELOC("getprop"), 
-					4, 1, prom_options,
-					RELOC("ibm,smt-snooze-delay"), 
-					option, 
-					sizeof(option));
-				if (option[0] != 0) {
-					found = 1;
-					/* Don't use simple_strtoul() because _ctype & others aren't RELOC'd */
-					my_smt_snooze_delay = 0;
-					q = option;
-					while (*q >= '0' && *q <= '9') {
-						my_smt_snooze_delay = my_smt_snooze_delay * 10 + *q - '0';
-						q++;
-					}
-				}
-			}
-		}
-
-		if (!found) {
-			my_smt_snooze_delay = 0; /* default value */
-		}
-	} else {
-		my_smt_snooze_delay = 0; /* default value */
-	}
-	_naca->smt_snooze_delay = my_smt_snooze_delay;
 	_naca->smt_state = my_smt_enabled;
 }
 

arch/ppc64/kernel/sysfs.c

@@ -9,6 +9,90 @@
 #include <asm/processor.h>
 #include <asm/cputable.h>
 #include <asm/hvcall.h>
+#include <asm/prom.h>
+
+
+/* SMT stuff */
+
+#ifndef CONFIG_PPC_ISERIES
+
+/* default to snooze disabled */
+DEFINE_PER_CPU(unsigned long, smt_snooze_delay);
+
+static ssize_t store_smt_snooze_delay(struct sys_device *dev, const char *buf,
+				      size_t count)
+{
+	struct cpu *cpu = container_of(dev, struct cpu, sysdev);
+	ssize_t ret;
+	unsigned long snooze;
+
+	ret = sscanf(buf, "%lu", &snooze);
+	if (ret != 1)
+		return -EINVAL;
+
+	per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
+
+	return count;
+}
+
+static ssize_t show_smt_snooze_delay(struct sys_device *dev, char *buf)
+{
+	struct cpu *cpu = container_of(dev, struct cpu, sysdev);
+
+	return sprintf(buf, "%lu\n", per_cpu(smt_snooze_delay, cpu->sysdev.id));
+}
+
+static SYSDEV_ATTR(smt_snooze_delay, 0644, show_smt_snooze_delay,
+		   store_smt_snooze_delay);
+
+/* Only parse OF options if the matching cmdline option was not specified */
+static int smt_snooze_cmdline;
+
+static int __init smt_setup(void)
+{
+	struct device_node *options;
+	unsigned int *val;
+	unsigned int cpu;
+
+	if (!cur_cpu_spec->cpu_features & CPU_FTR_SMT)
+		return 1;
+
+	options = find_path_device("/options");
+	if (!options)
+		return 1;
+
+	val = (unsigned int *)get_property(options, "ibm,smt-snooze-delay",
+					   NULL);
+	if (!smt_snooze_cmdline && val) {
+		for_each_cpu(cpu)
+			per_cpu(smt_snooze_delay, cpu) = *val;
+	}
+
+	return 1;
+}
+__initcall(smt_setup);
+
+static int __init setup_smt_snooze_delay(char *str)
+{
+	unsigned int cpu;
+	int snooze;
+
+	if (!cur_cpu_spec->cpu_features & CPU_FTR_SMT)
+		return 1;
+
+	smt_snooze_cmdline = 1;
+
+	if (get_option(&str, &snooze)) {
+		for_each_cpu(cpu)
+			per_cpu(smt_snooze_delay, cpu) = snooze;
+	}
+
+	return 1;
+}
+__setup("smt-snooze-delay=", setup_smt_snooze_delay);
+
+#endif
+
 
 /* PMC stuff */
 
@@ -235,6 +319,11 @@ static int __init topology_init(void)
 		register_cpu_pmc(&c->sysdev);
 
 		sysdev_create_file(&c->sysdev, &attr_physical_id);
+
+#ifndef CONFIG_PPC_ISERIES
+		if (cur_cpu_spec->cpu_features & CPU_FTR_SMT)
+			sysdev_create_file(&c->sysdev, &attr_smt_snooze_delay);
+#endif
 	}
 
 	return 0;

include/asm-ppc64/naca.h

@@ -37,12 +37,10 @@ struct naca_struct {
 	u32 dCacheL1LinesPerPage;	/* L1 d-cache lines / page   0x64 */
 	u32 iCacheL1LogLineSize;	/* L1 i-cache line size Log2 0x68 */
 	u32 iCacheL1LinesPerPage;	/* L1 i-cache lines / page   0x6c */
-	u64 smt_snooze_delay;           /* Delay (in usec) before    0x70 */
-                                        /* entering ST mode               */
-	u8  smt_state;                  /* 0 = SMT off               0x78 */
+	u8  smt_state;                  /* 0 = SMT off               0x70 */
 	                                /* 1 = SMT on                     */
 	                                /* 2 = SMT dynamic                */
-	u8  resv0[7];                   /* Reserved           0x70 - 0x7F */
+	u8  resv0[15];                  /* Reserved           0x71 - 0x7F */
 };
 
 extern struct naca_struct *naca;