[PATCH v2 1/7] dump_stack: Support adding to the dump stack arch description

@@ -198,6 +198,7 @@ u32 log_buf_len_get(void);
 void log_buf_vmcoreinfo_setup(void);
 void __init setup_log_buf(int early);
 __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
+__printf(1, 2) void dump_stack_add_arch_desc(const char *fmt, ...);
 void dump_stack_print_info(const char *log_lvl);
 void show_regs_print_info(const char *log_lvl);
 extern asmlinkage void dump_stack(void) __cold;

@@ -256,6 +257,10 @@ static inline __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...)
 {
 }
 
+static inline __printf(1, 2) void dump_stack_add_arch_desc(const char *fmt, ...)
+{
+}
+
 static inline void dump_stack_print_info(const char *log_lvl)
 {
 }

@@ -35,6 +35,64 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...)
 	va_end(args);
 }
 
+/**
+ * dump_stack_add_arch_desc - add arch-specific info to show with task dumps
+ * @fmt: printf-style format string
+ * @...: arguments for the format string
+ *
+ * See dump_stack_set_arch_desc() for why you'd want to use this.
+ *
+ * This version adds to any existing string already created with either
+ * dump_stack_set_arch_desc() or dump_stack_add_arch_desc(). If there is an
+ * existing string a space will be prepended to the passed string.
+ */
+void __init dump_stack_add_arch_desc(const char *fmt, ...)
+{
+	va_list args;
+	int pos, len;
+	char *p;
+
+	/*
+	 * If there's an existing string we snprintf() past the end of it, and
+	 * then turn the terminating NULL of the existing string into a space
+	 * to create one string separated by a space.
+	 *
+	 * If there's no existing string we just snprintf() to the buffer, like
+	 * dump_stack_set_arch_desc(), but without calling it because we'd need
+	 * a varargs version.
+	 */
+	len = strnlen(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str));
+	pos = len;
+
+	if (len)
+		pos++;
+
+	if (pos >= sizeof(dump_stack_arch_desc_str))
+		return; /* Ran out of space */
+
+	p = &dump_stack_arch_desc_str[pos];
+
+	va_start(args, fmt);
+	vsnprintf(p, sizeof(dump_stack_arch_desc_str) - pos, fmt, args);
+	va_end(args);
+
+	if (len) {
+		/*
+		 * Order the stores above in vsnprintf() vs the store of the
+		 * space below which joins the two strings. Note this doesn't
+		 * make the code truly race free because there is no barrier on
+		 * the read side. ie. Another CPU might load the uninitialised
+		 * tail of the buffer first and then the space below (rather
+		 * than the NULL that was there previously), and so print the
+		 * uninitialised tail. But the whole string lives in BSS so in
+		 * practice it should just see NULLs.
+		 */
+		smp_wmb();
+
+		dump_stack_arch_desc_str[len] = ' ';
+	}
+}
+
 /**
  * dump_stack_print_info - print generic debug info for dump_stack()
  * @log_lvl: log level

@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/export.h>
 #include <linux/jump_label.h>
+#include <linux/printk.h>
 
 #include <asm/oprofile_impl.h>
 #include <asm/cputable.h>

@@ -761,6 +761,10 @@ void __init early_init_devtree(void *params)
 
 	dt_cpu_ftrs_scan();
 
+	/* We can now set the CPU name & PVR for the oops output */
+	dump_stack_add_arch_desc("%s pvr:0x%04lx", cur_cpu_spec->cpu_name,
+				 mfspr(SPRN_PVR));
+
 	/* Retrieve CPU related informations from the flat tree
 	 * (altivec support, boot CPU ID, ...)
 	 */

@@ -371,8 +371,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 	 */
 	if (!dt_cpu_ftrs_in_use()) {
 		prop = of_get_flat_dt_prop(node, "cpu-version", NULL);
-		if (prop && (be32_to_cpup(prop) & 0xff000000) == 0x0f000000)
+		if (prop && (be32_to_cpup(prop) & 0xff000000) == 0x0f000000) {
 			identify_cpu(0, be32_to_cpup(prop));
+			dump_stack_add_arch_desc("lpvr:0x%04x", be32_to_cpup(prop));
+		}
 
 		check_cpu_feature_properties(node);
 		check_cpu_pa_features(node);

@@ -34,6 +34,7 @@
 #include <linux/of_fdt.h>
 #include <linux/libfdt.h>
 #include <linux/cpu.h>
+#include <linux/printk.h>
 
 #include <asm/prom.h>
 #include <asm/rtas.h>

@@ -687,6 +688,23 @@ static void __init tm_init(void)
 static void tm_init(void) { }
 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
 
+static int __init
+early_init_dt_scan_model(unsigned long node, const char *uname,
+			 int depth, void *data)
+{
+	const char *prop;
+
+	if (depth != 0)
+		return 0;
+
+	prop = of_get_flat_dt_prop(node, "model", NULL);
+	if (prop)
+		dump_stack_add_arch_desc("model:'%s'", prop);
+
+	/* break now */
+	return 1;
+}
+
 void __init early_init_devtree(void *params)
 {
 	phys_addr_t limit;

@@ -697,6 +715,8 @@ void __init early_init_devtree(void *params)
 	if (!early_init_dt_verify(params))
 		panic("BUG: Failed verifying flat device tree, bad version?");
 
+	of_scan_flat_dt(early_init_dt_scan_model, NULL);
+
 #ifdef CONFIG_PPC_RTAS
 	/* Some machines might need RTAS info for debugging, grab it now. */
 	of_scan_flat_dt(early_init_dt_scan_rtas, NULL);

@@ -21,6 +21,7 @@
 #include <linux/delay.h>
 #include <linux/initrd.h>
 #include <linux/platform_device.h>
+#include <linux/printk.h>
 #include <linux/seq_file.h>
 #include <linux/ioport.h>
 #include <linux/console.h>

@@ -638,6 +639,8 @@ void probe_machine(void)
 		for (;;);
 	}
 
+	dump_stack_add_arch_desc("machine:%s", ppc_md.name);
+
 	printk(KERN_INFO "Using %s machine description\n", ppc_md.name);
 }
 

@@ -156,8 +156,33 @@ static void __init pnv_setup_arch(void)
 	/* XXX PMCS */
 }
 
+static void __init pnv_add_dump_stack_arch_desc(void)
+{
+	struct device_node *dn;
+	const char *version;
+
+	dn = of_find_node_by_path("/ibm,opal/firmware");
+	if (!dn)
+		return;
+
+	version = of_get_property(dn, "version", NULL);
+	if (!version)
+		version = of_get_property(dn, "git-id", NULL);
+
+	if (version)
+		dump_stack_add_arch_desc("opal:%s", version);
+
+	version = of_get_property(dn, "mi-version", NULL);
+	if (version)
+		dump_stack_add_arch_desc("mi:%s", version);
+
+	of_node_put(dn);
+}
+
 static void __init pnv_init(void)
 {
+	pnv_add_dump_stack_arch_desc();
+
 	/*
 	 * Initialize the LPC bus now so that legacy serial
 	 * ports can be found on it

@@ -923,6 +923,39 @@ static void pSeries_cmo_feature_init(void)
 	pr_debug(" <- fw_cmo_feature_init()\n");
 }
 
+static void __init pseries_add_dump_stack_arch_desc(void)
+{
+	struct device_node *dn;
+	const char *prop;
+
+	dn = of_find_node_by_path("/openprom");
+	if (dn) {
+		prop = of_get_property(dn, "model", NULL);
+		if (prop)
+			dump_stack_add_arch_desc("of:'%s'", prop);
+
+		of_node_put(dn);
+	}
+
+	dn = of_find_node_by_path("/hypervisor");
+	if (dn) {
+		prop = of_get_property(dn, "compatible", NULL);
+		if (prop)
+			dump_stack_add_arch_desc("hv:%s", prop);
+
+		of_node_put(dn);
+	} else {
+		dn = of_find_node_by_path("/");
+		if (dn) {
+			prop = of_get_property(dn, "ibm,fw-net-version", NULL);
+			if (prop)
+				dump_stack_add_arch_desc("hv:phyp");
+
+			of_node_put(dn);
+		}
+	}
+}
+
 /*
  * Early initialization.  Relocation is on but do not reference unbolted pages
  */

@@ -930,6 +963,8 @@ static void __init pseries_init(void)
 {
 	pr_debug(" -> pseries_init()\n");
 
+	pseries_add_dump_stack_arch_desc();
+
 #ifdef CONFIG_HVC_CONSOLE
 	if (firmware_has_feature(FW_FEATURE_LPAR))
 		hvc_vio_init_early();