[S390] zfcpdump support.

s390 machines provide hardware support for creating Linux dumps on SCSI
disks. For creating a dump a special purpose dump Linux is used. The first
32 MB of memory are saved by the hardware before the dump Linux is
booted. Via an SCLP interface, the saved memory can be accessed from
Linux. This patch exports memory and registers of the crashed Linux to
userspace via a debugfs file. For more information refer to
Documentation/s390/zfcpdump.txt, which is included in this patch.

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

1 files changed, 651 insertions, 0 deletions

diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
new file mode 100644
index 000000000000..89d439316a53
--- /dev/null
+++ b/drivers/s390/char/zcore.c
@@ -0,0 +1,651 @@
+/*
+ * zcore module to export memory content and register sets for creating system
+ * dumps on SCSI disks (zfcpdump). The "zcore/mem" debugfs file shows the same
+ * dump format as s390 standalone dumps.
+ *
+ * For more information please refer to Documentation/s390/zfcpdump.txt
+ *
+ * Copyright IBM Corp. 2003,2007
+ * Author(s): Michael Holzheu
+ */
+
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/utsname.h>
+#include <linux/debugfs.h>
+#include <asm/ipl.h>
+#include <asm/sclp.h>
+#include <asm/setup.h>
+#include <asm/sigp.h>
+#include <asm/uaccess.h>
+#include <asm/debug.h>
+#include <asm/processor.h>
+#include <asm/irqflags.h>
+
+#define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
+#define MSG(x...) printk( KERN_ALERT x )
+#define ERROR_MSG(x...) printk ( KERN_ALERT "DUMP: " x )
+
+#define TO_USER		0
+#define TO_KERNEL	1
+
+enum arch_id {
+	ARCH_S390	= 0,
+	ARCH_S390X	= 1,
+};
+
+/* dump system info */
+
+struct sys_info {
+	enum arch_id	arch;
+	unsigned long	sa_base;
+	u32		sa_size;
+	int		cpu_map[NR_CPUS];
+	unsigned long	mem_size;
+	union save_area	lc_mask;
+};
+
+static struct sys_info sys_info;
+static struct debug_info *zcore_dbf;
+static int hsa_available;
+static struct dentry *zcore_dir;
+static struct dentry *zcore_file;
+
+/*
+ * Copy memory from HSA to kernel or user memory (not reentrant):
+ *
+ * @dest:  Kernel or user buffer where memory should be copied to
+ * @src:   Start address within HSA where data should be copied
+ * @count: Size of buffer, which should be copied
+ * @mode:  Either TO_KERNEL or TO_USER
+ */
+static int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
+{
+	int offs, blk_num;
+	static char buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
+
+	if (count == 0)
+		return 0;
+
+	/* copy first block */
+	offs = 0;
+	if ((src % PAGE_SIZE) != 0) {
+		blk_num = src / PAGE_SIZE + 2;
+		if (sclp_sdias_copy(buf, blk_num, 1)) {
+			TRACE("sclp_sdias_copy() failed\n");
+			return -EIO;
+		}
+		offs = min((PAGE_SIZE - (src % PAGE_SIZE)), count);
+		if (mode == TO_USER) {
+			if (copy_to_user((__force __user void*) dest,
+					 buf + (src % PAGE_SIZE), offs))
+				return -EFAULT;
+		} else
+			memcpy(dest, buf + (src % PAGE_SIZE), offs);
+	}
+	if (offs == count)
+		goto out;
+
+	/* copy middle */
+	for (; (offs + PAGE_SIZE) <= count; offs += PAGE_SIZE) {
+		blk_num = (src + offs) / PAGE_SIZE + 2;
+		if (sclp_sdias_copy(buf, blk_num, 1)) {
+			TRACE("sclp_sdias_copy() failed\n");
+			return -EIO;
+		}
+		if (mode == TO_USER) {
+			if (copy_to_user((__force __user void*) dest + offs,
+					 buf, PAGE_SIZE))
+				return -EFAULT;
+		} else
+			memcpy(dest + offs, buf, PAGE_SIZE);
+	}
+	if (offs == count)
+		goto out;
+
+	/* copy last block */
+	blk_num = (src + offs) / PAGE_SIZE + 2;
+	if (sclp_sdias_copy(buf, blk_num, 1)) {
+		TRACE("sclp_sdias_copy() failed\n");
+		return -EIO;
+	}
+	if (mode == TO_USER) {
+		if (copy_to_user((__force __user void*) dest + offs, buf,
+				 PAGE_SIZE))
+			return -EFAULT;
+	} else
+		memcpy(dest + offs, buf, count - offs);
+out:
+	return 0;
+}
+
+static int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
+{
+	return memcpy_hsa((void __force *) dest, src, count, TO_USER);
+}
+
+static int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
+{
+	return memcpy_hsa(dest, src, count, TO_KERNEL);
+}
+
+static int memcpy_real(void *dest, unsigned long src, size_t count)
+{
+	unsigned long flags;
+	int rc = -EFAULT;
+	register unsigned long _dest asm("2") = (unsigned long) dest;
+	register unsigned long _len1 asm("3") = (unsigned long) count;
+	register unsigned long _src  asm("4") = src;
+	register unsigned long _len2 asm("5") = (unsigned long) count;
+
+	if (count == 0)
+		return 0;
+	flags = __raw_local_irq_stnsm(0xf8); /* switch to real mode */
+	asm volatile (
+		"0:	mvcle	%1,%2,0x0\n"
+		"1:	jo	0b\n"
+		"	lhi	%0,0x0\n"
+		"2:\n"
+		EX_TABLE(1b,2b)
+		: "+d" (rc)
+		: "d" (_dest), "d" (_src), "d" (_len1), "d" (_len2)
+		: "cc", "memory");
+	__raw_local_irq_ssm(flags);
+
+	return rc;
+}
+
+static int memcpy_real_user(__user void *dest, unsigned long src, size_t count)
+{
+	static char buf[4096];
+	int offs = 0, size;
+
+	while (offs < count) {
+		size = min(sizeof(buf), count - offs);
+		if (memcpy_real(buf, src + offs, size))
+			return -EFAULT;
+		if (copy_to_user(dest + offs, buf, size))
+			return -EFAULT;
+		offs += size;
+	}
+	return 0;
+}
+
+#ifdef __s390x__
+/*
+ * Convert s390x (64 bit) cpu info to s390 (32 bit) cpu info
+ */
+static void __init s390x_to_s390_regs(union save_area *out, union save_area *in,
+				      int cpu)
+{
+	int i;
+
+	for (i = 0; i < 16; i++) {
+		out->s390.gp_regs[i] = in->s390x.gp_regs[i] & 0x00000000ffffffff;
+		out->s390.acc_regs[i] = in->s390x.acc_regs[i];
+		out->s390.ctrl_regs[i] =
+			in->s390x.ctrl_regs[i] & 0x00000000ffffffff;
+	}
+	/* locore for 31 bit has only space for fpregs 0,2,4,6 */
+	out->s390.fp_regs[0] = in->s390x.fp_regs[0];
+	out->s390.fp_regs[1] = in->s390x.fp_regs[2];
+	out->s390.fp_regs[2] = in->s390x.fp_regs[4];
+	out->s390.fp_regs[3] = in->s390x.fp_regs[6];
+	memcpy(&(out->s390.psw[0]), &(in->s390x.psw[0]), 4);
+	out->s390.psw[1] |= 0x8; /* set bit 12 */
+	memcpy(&(out->s390.psw[4]),&(in->s390x.psw[12]), 4);
+	out->s390.psw[4] |= 0x80; /* set (31bit) addressing bit */
+	out->s390.pref_reg = in->s390x.pref_reg;
+	out->s390.timer = in->s390x.timer;
+	out->s390.clk_cmp = in->s390x.clk_cmp;
+}
+
+static void __init s390x_to_s390_save_areas(void)
+{
+	int i = 1;
+	static union save_area tmp;
+
+	while (zfcpdump_save_areas[i]) {
+		s390x_to_s390_regs(&tmp, zfcpdump_save_areas[i], i);
+		memcpy(zfcpdump_save_areas[i], &tmp, sizeof(tmp));
+		i++;
+	}
+}
+
+#endif /* __s390x__ */
+
+static int __init init_cpu_info(enum arch_id arch)
+{
+	union save_area *sa;
+
+	/* get info for boot cpu from lowcore, stored in the HSA */
+
+	sa = kmalloc(sizeof(*sa), GFP_KERNEL);
+	if (!sa) {
+		ERROR_MSG("kmalloc failed: %s: %i\n",__FUNCTION__, __LINE__);
+		return -ENOMEM;
+	}
+	if (memcpy_hsa_kernel(sa, sys_info.sa_base, sys_info.sa_size) < 0) {
+		ERROR_MSG("could not copy from HSA\n");
+		kfree(sa);
+		return -EIO;
+	}
+	zfcpdump_save_areas[0] = sa;
+
+#ifdef __s390x__
+	/* convert s390x regs to s390, if we are dumping an s390 Linux */
+
+	if (arch == ARCH_S390)
+		s390x_to_s390_save_areas();
+#endif
+
+	return 0;
+}
+
+static DEFINE_MUTEX(zcore_mutex);
+
+#define DUMP_VERSION	0x3
+#define DUMP_MAGIC	0xa8190173618f23fdULL
+#define DUMP_ARCH_S390X	2
+#define DUMP_ARCH_S390	1
+#define HEADER_SIZE	4096
+
+/* dump header dumped according to s390 crash dump format */
+
+struct zcore_header {
+	u64 magic;
+	u32 version;
+	u32 header_size;
+	u32 dump_level;
+	u32 page_size;
+	u64 mem_size;
+	u64 mem_start;
+	u64 mem_end;
+	u32 num_pages;
+	u32 pad1;
+	u64 tod;
+	cpuid_t cpu_id;
+	u32 arch_id;
+	u32 build_arch;
+	char pad2[4016];
+} __attribute__((packed,__aligned__(16)));
+
+static struct zcore_header zcore_header = {
+	.magic		= DUMP_MAGIC,
+	.version	= DUMP_VERSION,
+	.header_size	= 4096,
+	.dump_level	= 0,
+	.page_size	= PAGE_SIZE,
+	.mem_start	= 0,
+#ifdef __s390x__
+	.build_arch	= DUMP_ARCH_S390X,
+#else
+	.build_arch	= DUMP_ARCH_S390,
+#endif
+};
+
+/*
+ * Copy lowcore info to buffer. Use map in order to copy only register parts.
+ *
+ * @buf:    User buffer
+ * @sa:     Pointer to save area
+ * @sa_off: Offset in save area to copy
+ * @len:    Number of bytes to copy
+ */
+static int copy_lc(void __user *buf, void *sa, int sa_off, int len)
+{
+	int i;
+	char *lc_mask = (char*)&sys_info.lc_mask;
+
+	for (i = 0; i < len; i++) {
+		if (!lc_mask[i + sa_off])
+			continue;
+		if (copy_to_user(buf + i, sa + sa_off + i, 1))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+/*
+ * Copy lowcores info to memory, if necessary
+ *
+ * @buf:   User buffer
+ * @addr:  Start address of buffer in dump memory
+ * @count: Size of buffer
+ */
+static int zcore_add_lc(char __user *buf, unsigned long start, size_t count)
+{
+	unsigned long end;
+	int i = 0;
+
+	if (count == 0)
+		return 0;
+
+	end = start + count;
+	while (zfcpdump_save_areas[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;
+
+		if (sys_info.arch == ARCH_S390)
+			prefix = zfcpdump_save_areas[i]->s390.pref_reg;
+		else
+			prefix = zfcpdump_save_areas[i]->s390x.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;
+		cp_start = max(start, sa_start);
+		cp_end = min(end, sa_end);
+
+		buf_off = cp_start - start;
+		sa_off = cp_start - sa_start;
+		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))
+			return -EFAULT;
+next:
+		i++;
+	}
+	return 0;
+}
+
+/*
+ * Read routine for zcore character device
+ * First 4K are dump header
+ * Next 32MB are HSA Memory
+ * Rest is read from absolute Memory
+ */
+static ssize_t zcore_read(struct file *file, char __user *buf, size_t count,
+			  loff_t *ppos)
+{
+	unsigned long mem_start; /* Start address in memory */
+	size_t mem_offs;	 /* Offset in dump memory */
+	size_t hdr_count;	 /* Size of header part of output buffer */
+	size_t size;
+	int rc;
+
+	mutex_lock(&zcore_mutex);
+
+	if (*ppos > (sys_info.mem_size + HEADER_SIZE)) {
+		rc = -EINVAL;
+		goto fail;
+	}
+
+	count = min(count, (size_t) (sys_info.mem_size + HEADER_SIZE - *ppos));
+
+	/* Copy dump header */
+	if (*ppos < HEADER_SIZE) {
+		size = min(count, (size_t) (HEADER_SIZE - *ppos));
+		if (copy_to_user(buf, &zcore_header + *ppos, size)) {
+			rc = -EFAULT;
+			goto fail;
+		}
+		hdr_count = size;
+		mem_start = 0;
+	} else {
+		hdr_count = 0;
+		mem_start = *ppos - HEADER_SIZE;
+	}
+
+	mem_offs = 0;
+
+	/* Copy from HSA data */
+	if (*ppos < (ZFCPDUMP_HSA_SIZE + HEADER_SIZE)) {
+		size = min((count - hdr_count), (size_t) (ZFCPDUMP_HSA_SIZE
+			   - mem_start));
+		rc = memcpy_hsa_user(buf + hdr_count, mem_start, size);
+		if (rc)
+			goto fail;
+
+		mem_offs += size;
+	}
+
+	/* Copy from real mem */
+	size = count - mem_offs - hdr_count;
+	rc = memcpy_real_user(buf + hdr_count + mem_offs, mem_start + mem_offs,
+			      size);
+	if (rc)
+		goto fail;
+
+	/*
+	 * Since s390 dump analysis tools like lcrash or crash
+	 * expect register sets in the prefix pages of the cpus,
+	 * we copy them into the read buffer, if necessary.
+	 * buf + hdr_count: Start of memory part of output buffer
+	 * mem_start: Start memory address to copy from
+	 * count - hdr_count: Size of memory area to copy
+	 */
+	if (zcore_add_lc(buf + hdr_count, mem_start, count - hdr_count)) {
+		rc = -EFAULT;
+		goto fail;
+	}
+	*ppos += count;
+fail:
+	mutex_unlock(&zcore_mutex);
+	return (rc < 0) ? rc : count;
+}
+
+static int zcore_open(struct inode *inode, struct file *filp)
+{
+	if (!hsa_available)
+		return -ENODATA;
+	else
+		return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
+}
+
+static int zcore_release(struct inode *inode, struct file *filep)
+{
+	diag308(DIAG308_REL_HSA, NULL);
+	hsa_available = 0;
+	return 0;
+}
+
+static loff_t zcore_lseek(struct file *file, loff_t offset, int orig)
+{
+	loff_t rc;
+
+	mutex_lock(&zcore_mutex);
+	switch (orig) {
+	case 0:
+		file->f_pos = offset;
+		rc = file->f_pos;
+		break;
+	case 1:
+		file->f_pos += offset;
+		rc = file->f_pos;
+		break;
+	default:
+		rc = -EINVAL;
+	}
+	mutex_unlock(&zcore_mutex);
+	return rc;
+}
+
+static struct file_operations zcore_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= zcore_lseek,
+	.read		= zcore_read,
+	.open		= zcore_open,
+	.release	= zcore_release,
+};
+
+
+static void __init set_s390_lc_mask(union save_area *map)
+{
+	memset(&map->s390.ext_save, 0xff, sizeof(map->s390.ext_save));
+	memset(&map->s390.timer, 0xff, sizeof(map->s390.timer));
+	memset(&map->s390.clk_cmp, 0xff, sizeof(map->s390.clk_cmp));
+	memset(&map->s390.psw, 0xff, sizeof(map->s390.psw));
+	memset(&map->s390.pref_reg, 0xff, sizeof(map->s390.pref_reg));
+	memset(&map->s390.acc_regs, 0xff, sizeof(map->s390.acc_regs));
+	memset(&map->s390.fp_regs, 0xff, sizeof(map->s390.fp_regs));
+	memset(&map->s390.gp_regs, 0xff, sizeof(map->s390.gp_regs));
+	memset(&map->s390.ctrl_regs, 0xff, sizeof(map->s390.ctrl_regs));
+}
+
+static void __init set_s390x_lc_mask(union save_area *map)
+{
+	memset(&map->s390x.fp_regs, 0xff, sizeof(map->s390x.fp_regs));
+	memset(&map->s390x.gp_regs, 0xff, sizeof(map->s390x.gp_regs));
+	memset(&map->s390x.psw, 0xff, sizeof(map->s390x.psw));
+	memset(&map->s390x.pref_reg, 0xff, sizeof(map->s390x.pref_reg));
+	memset(&map->s390x.fp_ctrl_reg, 0xff, sizeof(map->s390x.fp_ctrl_reg));
+	memset(&map->s390x.tod_reg, 0xff, sizeof(map->s390x.tod_reg));
+	memset(&map->s390x.timer, 0xff, sizeof(map->s390x.timer));
+	memset(&map->s390x.clk_cmp, 0xff, sizeof(map->s390x.clk_cmp));
+	memset(&map->s390x.acc_regs, 0xff, sizeof(map->s390x.acc_regs));
+	memset(&map->s390x.ctrl_regs, 0xff, sizeof(map->s390x.ctrl_regs));
+}
+
+/*
+ * Initialize dump globals for a given architecture
+ */
+static int __init sys_info_init(enum arch_id arch)
+{
+	switch (arch) {
+	case ARCH_S390X:
+		MSG("DETECTED 'S390X (64 bit) OS'\n");
+		sys_info.sa_base = SAVE_AREA_BASE_S390X;
+		sys_info.sa_size = sizeof(struct save_area_s390x);
+		set_s390x_lc_mask(&sys_info.lc_mask);
+		break;
+	case ARCH_S390:
+		MSG("DETECTED 'S390 (32 bit) OS'\n");
+		sys_info.sa_base = SAVE_AREA_BASE_S390;
+		sys_info.sa_size = sizeof(struct save_area_s390);
+		set_s390_lc_mask(&sys_info.lc_mask);
+		break;
+	default:
+		ERROR_MSG("unknown architecture 0x%x.\n",arch);
+		return -EINVAL;
+	}
+	sys_info.arch = arch;
+	if (init_cpu_info(arch)) {
+		ERROR_MSG("get cpu info failed\n");
+		return -ENOMEM;
+	}
+	sys_info.mem_size = real_memory_size;
+
+	return 0;
+}
+
+static int __init check_sdias(void)
+{
+	int rc, act_hsa_size;
+
+	rc = sclp_sdias_blk_count();
+	if (rc < 0) {
+		ERROR_MSG("Could not determine HSA size\n");
+		return rc;
+	}
+	act_hsa_size = (rc - 1) * PAGE_SIZE;
+	if (act_hsa_size < ZFCPDUMP_HSA_SIZE) {
+		ERROR_MSG("HSA size too small: %i\n", act_hsa_size);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void __init zcore_header_init(int arch, struct zcore_header *hdr)
+{
+	if (arch == ARCH_S390X)
+		hdr->arch_id = DUMP_ARCH_S390X;
+	else
+		hdr->arch_id = DUMP_ARCH_S390;
+	hdr->mem_size = sys_info.mem_size;
+	hdr->mem_end = sys_info.mem_size;
+	hdr->num_pages = sys_info.mem_size / PAGE_SIZE;
+	hdr->tod = get_clock();
+	get_cpu_id(&hdr->cpu_id);
+}
+
+extern int sdias_init(void);
+
+static int __init zcore_init(void)
+{
+	unsigned char arch;
+	int rc;
+
+	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
+		return -ENODATA;
+
+	zcore_dbf = debug_register("zcore", 4, 1, 4 * sizeof(long));
+	debug_register_view(zcore_dbf, &debug_sprintf_view);
+	debug_set_level(zcore_dbf, 6);
+
+	TRACE("devno:  %x\n", ipl_info.data.fcp.dev_id.devno);
+	TRACE("wwpn:   %llx\n", (unsigned long long) ipl_info.data.fcp.wwpn);
+	TRACE("lun:    %llx\n", (unsigned long long) ipl_info.data.fcp.lun);
+
+	rc = sdias_init();
+	if (rc)
+		goto fail;
+
+	rc = check_sdias();
+	if (rc) {
+		ERROR_MSG("Dump initialization failed\n");
+		goto fail;
+	}
+
+	rc = memcpy_hsa_kernel(&arch, __LC_AR_MODE_ID, 1);
+	if (rc) {
+		ERROR_MSG("sdial memcpy for arch id failed\n");
+		goto fail;
+	}
+
+#ifndef __s390x__
+	if (arch == ARCH_S390X) {
+		ERROR_MSG("32 bit dumper can't dump 64 bit system!\n");
+		rc = -EINVAL;
+		goto fail;
+	}
+#endif
+
+	rc = sys_info_init(arch);
+	if (rc) {
+		ERROR_MSG("arch init failed\n");
+		goto fail;
+	}
+
+	zcore_header_init(arch, &zcore_header);
+
+	zcore_dir = debugfs_create_dir("zcore" , NULL);
+	if (!zcore_dir) {
+		rc = -ENOMEM;
+		goto fail;
+	}
+	zcore_file = debugfs_create_file("mem", S_IRUSR, zcore_dir, NULL,
+					 &zcore_fops);
+	if (!zcore_file) {
+		debugfs_remove(zcore_dir);
+		rc = -ENOMEM;
+		goto fail;
+	}
+	hsa_available = 1;
+	return 0;
+
+fail:
+	diag308(DIAG308_REL_HSA, NULL);
+	return rc;
+}
+
+extern void sdias_exit(void);
+
+static void __exit zcore_exit(void)
+{
+	debug_unregister(zcore_dbf);
+	sdias_exit();
+	diag308(DIAG308_REL_HSA, NULL);
+}
+
+MODULE_AUTHOR("Copyright IBM Corp. 2003,2007");
+MODULE_DESCRIPTION("zcore module for zfcpdump support");
+MODULE_LICENSE("GPL");
+
+subsys_initcall(zcore_init);
+module_exit(zcore_exit);