s390: Remove zfcpdump NR_CPUS dependency

Currently zfpcdump can only collect registers for up to CONFIG_NR_CPUS
CPUss. This dependency is not necessary. So remove it by dynamically
allocating the save area array.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/ipl.h

@@ -7,6 +7,7 @@
 #ifndef _ASM_S390_IPL_H
 #define _ASM_S390_IPL_H
 
+#include <asm/lowcore.h>
 #include <asm/types.h>
 #include <asm/cio.h>
 #include <asm/setup.h>
@@ -88,6 +89,14 @@ extern u32 ipl_flags;
 extern u32 dump_prefix_page;
 extern unsigned int zfcpdump_prefix_array[];
 
+struct dump_save_areas {
+	struct save_area **areas;
+	int count;
+};
+
+extern struct dump_save_areas dump_save_areas;
+struct save_area *dump_save_area_create(int cpu);
+
 extern void do_reipl(void);
 extern void do_halt(void);
 extern void do_poff(void);

arch/s390/include/asm/smp.h

@@ -14,7 +14,6 @@
 #define raw_smp_processor_id()	(S390_lowcore.cpu_nr)
 
 extern struct mutex smp_cpu_state_mutex;
-extern struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
 
 extern int __cpu_up(unsigned int cpu, struct task_struct *tidle);
 

arch/s390/kernel/crash_dump.c

@@ -22,6 +22,32 @@
 #define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
 #define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
 
+struct dump_save_areas dump_save_areas;
+
+/*
+ * Allocate and add a save area for a CPU
+ */
+struct save_area *dump_save_area_create(int cpu)
+{
+	struct save_area **save_areas, *save_area;
+
+	save_area = kmalloc(sizeof(*save_area), GFP_KERNEL);
+	if (!save_area)
+		return NULL;
+	if (cpu + 1 > dump_save_areas.count) {
+		dump_save_areas.count = cpu + 1;
+		save_areas = krealloc(dump_save_areas.areas,
+				      dump_save_areas.count * sizeof(void *),
+				      GFP_KERNEL | __GFP_ZERO);
+		if (!save_areas) {
+			kfree(save_area);
+			return NULL;
+		}
+		dump_save_areas.areas = save_areas;
+	}
+	dump_save_areas.areas[cpu] = save_area;
+	return save_area;
+}
 
 /*
  * Return physical address for virtual address
@@ -450,8 +476,8 @@ static int get_cpu_cnt(void)
 {
 	int i, cpus = 0;
 
-	for (i = 0; zfcpdump_save_areas[i]; i++) {
-		if (zfcpdump_save_areas[i]->pref_reg == 0)
+	for (i = 0; i < dump_save_areas.count; i++) {
+		if (dump_save_areas.areas[i]->pref_reg == 0)
 			continue;
 		cpus++;
 	}
@@ -522,8 +548,8 @@ static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
 
 	ptr = nt_prpsinfo(ptr);
 
-	for (i = 0; zfcpdump_save_areas[i]; i++) {
-		sa = zfcpdump_save_areas[i];
+	for (i = 0; i < dump_save_areas.count; i++) {
+		sa = dump_save_areas.areas[i];
 		if (sa->pref_reg == 0)
 			continue;
 		ptr = fill_cpu_elf_notes(ptr, sa);

arch/s390/kernel/smp.c

@@ -533,9 +533,6 @@ EXPORT_SYMBOL(smp_ctl_clear_bit);
 
 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_CRASH_DUMP)
 
-struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
-EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
-
 static void __init smp_get_save_area(int cpu, u16 address)
 {
 	void *lc = pcpu_devices[0].lowcore;
@@ -546,15 +543,9 @@ static void __init smp_get_save_area(int cpu, u16 address)
 	if (!OLDMEM_BASE && (address == boot_cpu_address ||
 			     ipl_info.type != IPL_TYPE_FCP_DUMP))
 		return;
-	if (cpu >= NR_CPUS) {
-		pr_warning("CPU %i exceeds the maximum %i and is excluded "
-			   "from the dump\n", cpu, NR_CPUS - 1);
-		return;
-	}
-	save_area = kmalloc(sizeof(struct save_area), GFP_KERNEL);
+	save_area = dump_save_area_create(cpu);
 	if (!save_area)
 		panic("could not allocate memory for save area\n");
-	zfcpdump_save_areas[cpu] = save_area;
 #ifdef CONFIG_CRASH_DUMP
 	if (address == boot_cpu_address) {
 		/* Copy the registers of the boot cpu. */

drivers/s390/char/zcore.c

@@ -151,7 +151,7 @@ static int __init init_cpu_info(enum arch_id arch)
 
 	/* get info for boot cpu from lowcore, stored in the HSA */
 
-	sa = kmalloc(sizeof(*sa), GFP_KERNEL);
+	sa = dump_save_area_create(0);
 	if (!sa)
 		return -ENOMEM;
 	if (memcpy_hsa_kernel(sa, sys_info.sa_base, sys_info.sa_size) < 0) {
@@ -159,7 +159,6 @@ static int __init init_cpu_info(enum arch_id arch)
 		kfree(sa);
 		return -EIO;
 	}
-	zfcpdump_save_areas[0] = sa;
 	return 0;
 }
 
@@ -246,24 +245,25 @@ static int copy_lc(void __user *buf, void *sa, int sa_off, int len)
 static int zcore_add_lc(char __user *buf, unsigned long start, size_t count)
 {
 	unsigned long end;
-	int i = 0;
+	int i;
 
 	if (count == 0)
 		return 0;
 
 	end = start + count;
-	while (zfcpdump_save_areas[i]) {
+	for (i = 0; i < dump_save_areas.count; i++) {
 		unsigned long cp_start, cp_end; /* copy range */
 		unsigned long sa_start, sa_end; /* save area range */
 		unsigned long prefix;
 		unsigned long sa_off, len, buf_off;
+		struct save_area *save_area = dump_save_areas.areas[i];
 
-		prefix = zfcpdump_save_areas[i]->pref_reg;
+		prefix = save_area->pref_reg;
 		sa_start = prefix + sys_info.sa_base;
 		sa_end = prefix + sys_info.sa_base + sys_info.sa_size;
 
 		if ((end < sa_start) || (start > sa_end))
-			goto next;
+			continue;
 		cp_start = max(start, sa_start);
 		cp_end = min(end, sa_end);
 
@@ -272,10 +272,8 @@ static int zcore_add_lc(char __user *buf, unsigned long start, size_t count)
 		len = cp_end - cp_start;
 
 		TRACE("copy_lc for: %lx\n", start);
-		if (copy_lc(buf + buf_off, zfcpdump_save_areas[i], sa_off, len))
+		if (copy_lc(buf + buf_off, save_area, sa_off, len))
 			return -EFAULT;
-next:
-		i++;
 	}
 	return 0;
 }
@@ -637,8 +635,8 @@ static void __init zcore_header_init(int arch, struct zcore_header *hdr,
 	hdr->num_pages = mem_size / PAGE_SIZE;
 	hdr->tod = get_tod_clock();
 	get_cpu_id(&hdr->cpu_id);
-	for (i = 0; zfcpdump_save_areas[i]; i++) {
-		prefix = zfcpdump_save_areas[i]->pref_reg;
+	for (i = 0; i < dump_save_areas.count; i++) {
+		prefix = dump_save_areas.areas[i]->pref_reg;
 		hdr->real_cpu_cnt++;
 		if (!prefix)
 			continue;