[PATCH kernel RFC 0/2] powerpc/pseries: Kexec style boot

@@ -1261,7 +1261,7 @@ static void __init prom_parse_platform_support(u8 index, u8 val,
 	}
 }
 
-static void __init prom_check_platform_support(void)
+struct ibm_arch_vec __init *prom_check_platform_support(int prop_len)
 {
 	struct platform_support supported = {
 		.hash_mmu = false,

@@ -1269,8 +1269,6 @@ static void __init prom_check_platform_support(void)
 		.radix_gtse = false,
 		.xive = false
 	};
-	int prop_len = prom_getproplen(prom.chosen,
-				       "ibm,arch-vec-5-platform-support");
 
 	/*
 	 * First copy the architecture vec template

@@ -1319,7 +1317,12 @@ static void __init prom_check_platform_support(void)
 		prom_debug("Asking for XIVE\n");
 		ibm_architecture_vec.vec5.intarch = OV5_FEAT(OV5_XIVE_EXPLOIT);
 	}
+
+	ibm_architecture_vec.vec5.max_cpus = cpu_to_be32(NR_CPUS);
+
+	return &ibm_architecture_vec;
 }
+EXPORT_SYMBOL_GPL(prom_check_platform_support);
 
 static void __init prom_send_capabilities(void)
 {

@@ -1328,7 +1331,8 @@ static void __init prom_send_capabilities(void)
 	u32 cores;
 
 	/* Check ibm,arch-vec-5-platform-support and fixup vec5 if required */
-	prom_check_platform_support();
+	prom_check_platform_support(prom_getproplen(prom.chosen,
+				"ibm,arch-vec-5-platform-support"));
 
 	root = call_prom("open", 1, 1, ADDR("/"));
 	if (root != 0) {

@@ -284,12 +284,53 @@ void __init record_spr_defaults(void)
  * device-tree is not accessible via normal means at this point.
  */
 
+/*
+ * The architecture vector has an array of PVR mask/value pairs,
+ * followed by # option vectors - 1, followed by the option vectors.
+ *
+ * See prom.h for the definition of the bits specified in the
+ * architecture vector.
+ */
+
+extern struct ibm_arch_vec __init *prom_check_platform_support(
+		int vec5_prop_len);
+
+int __init early_init_dt_scan_chosen_h_cas(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+	int l;
+	const char *p;
+
+	if (depth != 1 || !data ||
+	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
+		return 0;
+	p = of_get_flat_dt_prop(node, "qemu,h_cas", &l);
+	if (p != NULL && l > 0)
+		*(bool *) data = be32_to_cpu(*(uint32_t *) p) != 0;
+
+	return 1;
+}
+
 void __init early_setup(unsigned long dt_ptr)
 {
 	static __initdata struct paca_struct boot_paca;
+	struct ibm_arch_vec *vec = prom_check_platform_support(0);
 
 	/* -------- printk is _NOT_ safe to use here ! ------- */
 
+	/* ibm,client-architecture-support support */
+#define KVMPPC_HCALL_BASE       0xf000
+#define KVMPPC_H_CAS            (KVMPPC_HCALL_BASE + 0x2)
+#define FDT_MAX_SIZE 0x100000
+	bool do_h_cas = false;
+
+	if (early_init_dt_verify(__va(dt_ptr))) {
+		of_scan_flat_dt(early_init_dt_scan_chosen_h_cas, &do_h_cas);
+		if (do_h_cas)
+			plpar_hcall_norets(KVMPPC_H_CAS, vec, dt_ptr,
+					FDT_MAX_SIZE);
+	}
+
 	/* Try new device tree based feature discovery ... */
 	if (!dt_cpu_ftrs_init(__va(dt_ptr)))
 		/* Otherwise use the old style CPU table */

@@ -59,6 +59,7 @@ struct rtas_t {
 	arch_spinlock_t lock;
 	struct rtas_args args;
 	struct device_node *dev;	/* virtual address pointer */
+	bool hcall;
 };
 
 struct rtas_suspend_me_data {

@@ -49,6 +49,14 @@ struct rtas_t rtas = {
 };
 EXPORT_SYMBOL(rtas);
 
+static void __enter_rtas(unsigned long pa)
+{
+	if (rtas.hcall)
+		plpar_hcall_norets(H_RTAS, pa);
+	else
+		enter_rtas(pa);
+}
+
 DEFINE_SPINLOCK(rtas_data_buf_lock);
 EXPORT_SYMBOL(rtas_data_buf_lock);
 

@@ -95,9 +103,6 @@ static void call_rtas_display_status(unsigned char c)
 {
 	unsigned long s;
 
-	if (!rtas.base)
-		return;
-
 	s = lock_rtas();
 	rtas_call_unlocked(&rtas.args, 10, 1, 1, NULL, c);
 	unlock_rtas(s);

@@ -145,9 +150,6 @@ static void udbg_rtascon_putc(char c)
 {
 	int tries;
 
-	if (!rtas.base)
-		return;
-
 	/* Add CRs before LFs */
 	if (c == '\n')
 		udbg_rtascon_putc('\r');

@@ -164,9 +166,6 @@ static int udbg_rtascon_getc_poll(void)
 {
 	int c;
 
-	if (!rtas.base)
-		return -1;
-
 	if (rtas_call(rtas_getchar_token, 0, 2, &c))
 		return -1;
 

@@ -205,9 +204,6 @@ void rtas_progress(char *s, unsigned short hex)
 	static int current_line;
 	static int pending_newline = 0;  /* did last write end with unprinted newline? */
 
-	if (!rtas.base)
-		return;
-
 	if (display_width == 0) {
 		display_width = 0x10;
 		if ((root = of_find_node_by_path("/rtas"))) {

@@ -382,7 +378,7 @@ static char *__fetch_rtas_last_error(char *altbuf)
 	save_args = rtas.args;
 	rtas.args = err_args;
 
-	enter_rtas(__pa(&rtas.args));
+	__enter_rtas(__pa(&rtas.args));
 
 	err_args = rtas.args;
 	rtas.args = save_args;

@@ -428,7 +424,7 @@ va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
 	for (i = 0; i < nret; ++i)
 		args->rets[i] = 0;
 
-	enter_rtas(__pa(args));
+	__enter_rtas(__pa(args));
 }
 
 void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret, ...)

@@ -449,7 +445,7 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
 	char *buff_copy = NULL;
 	int ret;
 
-	if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
+	if (token == RTAS_UNKNOWN_SERVICE)
 		return -1;
 
 	s = lock_rtas();

@@ -1064,9 +1060,6 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	if (!rtas.entry)
-		return -EINVAL;
-
 	if (copy_from_user(&args, uargs, 3 * sizeof(u32)) != 0)
 		return -EFAULT;
 

@@ -1115,7 +1108,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
 	flags = lock_rtas();
 
 	rtas.args = args;
-	enter_rtas(__pa(&rtas.args));
+	__enter_rtas(__pa(&rtas.args));
 	args = rtas.args;
 
 	/* A -1 return code indicates that the last command couldn't

@@ -1149,8 +1142,8 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
 void __init rtas_initialize(void)
 {
 	unsigned long rtas_region = RTAS_INSTANTIATE_MAX;
-	u32 base, size, entry;
-	int no_base, no_size, no_entry;
+	u32 base = 0, size = 0, entry = 0, do_h_rtas = 0;
+	int no_base, no_size, no_entry, ret;
 
 	/* Get RTAS dev node and fill up our "rtas" structure with infos
 	 * about it.

@@ -1161,17 +1154,15 @@ void __init rtas_initialize(void)
 
 	no_base = of_property_read_u32(rtas.dev, "linux,rtas-base", &base);
 	no_size = of_property_read_u32(rtas.dev, "rtas-size", &size);
-	if (no_base || no_size) {
-		of_node_put(rtas.dev);
-		rtas.dev = NULL;
-		return;
-	}
 
 	rtas.base = base;
 	rtas.size = size;
 	no_entry = of_property_read_u32(rtas.dev, "linux,rtas-entry", &entry);
 	rtas.entry = no_entry ? rtas.base : entry;
 
+	ret = of_property_read_u32(of_chosen, "qemu,h_rtas", &do_h_rtas);
+	rtas.hcall = !ret && do_h_rtas;
+
 	/* If RTAS was found, allocate the RMO buffer for it and look for
 	 * the stop-self token if any
 	 */

@@ -1208,6 +1199,10 @@ int __init early_init_dt_scan_rtas(unsigned long node,
 		rtas.base = *basep;
 		rtas.entry = *entryp;
 		rtas.size = *sizep;
+	} else {
+		rtas.base = 0;
+		rtas.entry = 0;
+		rtas.size = 0;
 	}
 
 #ifdef CONFIG_UDBG_RTAS_CONSOLE