s390/zcore: remove /sys/kernel/debug/zcore/mem

New versions of the SCSI dumper use the /dev/vmcore interface instead
of zcore mem. Remove the outdated interface.

Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Documentation/s390/zfcpdump.txt

@@ -15,19 +15,15 @@ the s390-tools package) to make the device bootable. The operator of a Linux
 system can then trigger a SCSI dump by booting the SCSI disk, where zfcpdump
 resides on.
 
-The kernel part of zfcpdump is implemented as a debugfs file under "zcore/mem",
-which exports memory and registers of the crashed Linux in an s390
-standalone dump format. It can be used in the same way as e.g. /dev/mem. The
-dump format defines a 4K header followed by plain uncompressed memory. The
-register sets are stored in the prefix pages of the respective CPUs. To build a
-dump enabled kernel with the zcore driver, the kernel config option
-CONFIG_CRASH_DUMP has to be set. When reading from "zcore/mem", the part of
-memory, which has been saved by hardware is read by the driver via the SCLP
-hardware interface. The second part is just copied from the non overwritten real
-memory.
-
-Since kernel version 3.12 also the /proc/vmcore file can also be used to access
-the dump.
+The user space dump tool accesses the memory of the crashed system by means
+of the /proc/vmcore interface. This interface exports the crashed system's
+memory and registers in ELF core dump format. To access the memory which has
+been saved by the hardware SCLP requests will be created at the time the data
+is needed by /proc/vmcore. The tail part of the crashed systems memory which
+has not been stashed by hardware can just be copied from real memory.
+
+To build a dump enabled kernel the kernel config option CONFIG_CRASH_DUMP
+has to be set.
 
 To get a valid zfcpdump kernel configuration use "make zfcpdump_defconfig".
 

arch/s390/include/asm/lowcore.h

@@ -35,7 +35,6 @@ struct save_area {
 struct save_area_ext {
 	struct save_area	sa;
 	__vector128		vx_regs[32];
-	u64			vx_sa_addr;
 };
 
 struct _lowcore {

drivers/s390/char/Makefile

@@ -30,9 +30,7 @@ obj-$(CONFIG_S390_TAPE_3590) += tape_3590.o
 obj-$(CONFIG_MONREADER) += monreader.o
 obj-$(CONFIG_MONWRITER) += monwriter.o
 obj-$(CONFIG_S390_VMUR) += vmur.o
-
-zcore_mod-objs := sclp_sdias.o zcore.o
-obj-$(CONFIG_CRASH_DUMP) += zcore_mod.o
+obj-$(CONFIG_CRASH_DUMP) += sclp_sdias.o zcore.o
 
 hmcdrv-objs := hmcdrv_mod.o hmcdrv_dev.o hmcdrv_ftp.o hmcdrv_cache.o diag_ftp.o sclp_ftp.o
 obj-$(CONFIG_HMC_DRV) += hmcdrv.o

drivers/s390/char/zcore.c

@@ -43,27 +43,14 @@ enum arch_id {
 	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;
-	struct save_area lc_mask;
-};
-
 struct ipib_info {
 	unsigned long	ipib;
 	u32		checksum;
 }  __attribute__((packed));
 
-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;
 static struct dentry *zcore_memmap_file;
 static struct dentry *zcore_reipl_file;
 static struct dentry *zcore_hsa_file;
@@ -149,171 +136,22 @@ static int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
 	return memcpy_hsa(dest, src, count, TO_KERNEL);
 }
 
-static int __init init_cpu_info(enum arch_id arch)
+static int __init init_cpu_info(void)
 {
 	struct save_area_ext *sa_ext;
-	struct _lowcore *lc;
-	void *ptr;
-	int i;
 
 	/* get info for boot cpu from lowcore, stored in the HSA */
 
 	sa_ext = dump_save_areas.areas[0];
 	if (!sa_ext)
 		return -ENOMEM;
-	if (memcpy_hsa_kernel(&sa_ext->sa, sys_info.sa_base,
-			      sys_info.sa_size) < 0) {
+	if (memcpy_hsa_kernel(&sa_ext->sa, SAVE_AREA_BASE,
+			      sizeof(struct save_area)) < 0) {
 		TRACE("could not copy from HSA\n");
 		return -EIO;
 	}
-	if (!MACHINE_HAS_VX)
-		return 0;
-
-	save_vx_regs_safe(sa_ext->vx_regs);
-	/* Get address of the vector register save area for each CPU */
-	for (i = 0; i < dump_save_areas.count; i++) {
-		sa_ext = dump_save_areas.areas[i];
-		lc = (struct _lowcore *)(unsigned long) sa_ext->sa.pref_reg;
-		ptr = &lc->vector_save_area_addr;
-		copy_from_oldmem(&sa_ext->vx_sa_addr, ptr,
-				 sizeof(sa_ext->vx_sa_addr));
-	}
-	return 0;
-}
-
-static DEFINE_MUTEX(zcore_mutex);
-
-#define DUMP_VERSION	0x5
-#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;
-	struct cpuid cpu_id;
-	u32 arch_id;
-	u32 volnr;
-	u32 build_arch;
-	u64 rmem_size;
-	u8 mvdump;
-	u16 cpu_cnt;
-	u16 real_cpu_cnt;
-	u8 end_pad1[0x200-0x061];
-	u64 mvdump_sign;
-	u64 mvdump_zipl_time;
-	u8 end_pad2[0x800-0x210];
-	u32 lc_vec[512];
-} __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,
-	.build_arch	= DUMP_ARCH_S390X,
-};
-
-/*
- * 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)
-{
-	struct save_area_ext *sa_ext;
-	struct save_area *sa;
-	unsigned long end;
-	int i;
-
-	if (count == 0)
-		return 0;
-
-	end = start + count;
-	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 sa_off, len, buf_off;
-
-		sa_ext = dump_save_areas.areas[i];
-		sa = &sa_ext->sa;
-
-		/* Copy the 512 bytes lowcore save area 0x1200 - 0x1400 */
-		sa_start = sa->pref_reg + sys_info.sa_base;
-		sa_end = sa_start + sys_info.sa_size;
-
-		if (end >= sa_start && start < sa_end) {
-			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: %lx-%lx\n", cp_start, cp_end);
-			if (copy_lc(buf + buf_off, sa, sa_off, len))
-				return -EFAULT;
-		}
-
-		if (!MACHINE_HAS_VX)
-			continue;
-
-		/* Copy the 512 bytes vector save area */
-		sa_start = sa_ext->vx_sa_addr & -1024UL;
-		sa_end = sa_start + 512;
-
-		if (end >= sa_start && start < sa_end) {
-			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 vxrs: %lx-%lx\n", cp_start, cp_end);
-			if (copy_to_user(buf + buf_off,
-					 (void *) &sa_ext->vx_regs + sa_off,
-					 len))
-				return -EFAULT;
-		}
-	}
+	if (MACHINE_HAS_VX)
+		save_vx_regs_safe(sa_ext->vx_regs);
 	return 0;
 }
 
@@ -326,126 +164,6 @@ static void release_hsa(void)
 	hsa_available = 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 < sclp.hsa_size + HEADER_SIZE) {
-		size = min((count - hdr_count),
-			   (size_t) (sclp.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 = copy_to_user_real(buf + hdr_count + mem_offs,
-			       (void *) 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)
-{
-	if (hsa_available)
-		release_hsa();
-	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 const struct file_operations zcore_fops = {
-	.owner		= THIS_MODULE,
-	.llseek		= zcore_lseek,
-	.read		= zcore_read,
-	.open		= zcore_open,
-	.release	= zcore_release,
-};
-
 static ssize_t zcore_memmap_read(struct file *filp, char __user *buf,
 				 size_t count, loff_t *ppos)
 {
@@ -549,50 +267,6 @@ static const struct file_operations zcore_hsa_fops = {
 	.llseek		= no_llseek,
 };
 
-static void __init set_lc_mask(struct save_area *map)
-{
-	memset(&map->fp_regs, 0xff, sizeof(map->fp_regs));
-	memset(&map->gp_regs, 0xff, sizeof(map->gp_regs));
-	memset(&map->psw, 0xff, sizeof(map->psw));
-	memset(&map->pref_reg, 0xff, sizeof(map->pref_reg));
-	memset(&map->fp_ctrl_reg, 0xff, sizeof(map->fp_ctrl_reg));
-	memset(&map->tod_reg, 0xff, sizeof(map->tod_reg));
-	memset(&map->timer, 0xff, sizeof(map->timer));
-	memset(&map->clk_cmp, 0xff, sizeof(map->clk_cmp));
-	memset(&map->acc_regs, 0xff, sizeof(map->acc_regs));
-	memset(&map->ctrl_regs, 0xff, sizeof(map->ctrl_regs));
-}
-
-/*
- * Initialize dump globals for a given architecture
- */
-static int __init sys_info_init(enum arch_id arch, unsigned long mem_end)
-{
-	int rc;
-
-	switch (arch) {
-	case ARCH_S390X:
-		pr_alert("DETECTED 'S390X (64 bit) OS'\n");
-		break;
-	case ARCH_S390:
-		pr_alert("DETECTED 'S390 (32 bit) OS'\n");
-		break;
-	default:
-		pr_alert("0x%x is an unknown architecture.\n",arch);
-		return -EINVAL;
-	}
-	sys_info.sa_base = SAVE_AREA_BASE;
-	sys_info.sa_size = sizeof(struct save_area);
-	sys_info.arch = arch;
-	set_lc_mask(&sys_info.lc_mask);
-	rc = init_cpu_info(arch);
-	if (rc)
-		return rc;
-	sys_info.mem_size = mem_end;
-
-	return 0;
-}
-
 static int __init check_sdias(void)
 {
 	if (!sclp.hsa_size) {
@@ -602,43 +276,6 @@ static int __init check_sdias(void)
 	return 0;
 }
 
-static int __init get_mem_info(unsigned long *mem, unsigned long *end)
-{
-	struct memblock_region *reg;
-
-	for_each_memblock(memory, reg) {
-		*mem += reg->size;
-		*end = max_t(unsigned long, *end, reg->base + reg->size);
-	}
-	return 0;
-}
-
-static void __init zcore_header_init(int arch, struct zcore_header *hdr,
-				     unsigned long mem_size)
-{
-	u32 prefix;
-	int i;
-
-	if (arch == ARCH_S390X)
-		hdr->arch_id = DUMP_ARCH_S390X;
-	else
-		hdr->arch_id = DUMP_ARCH_S390;
-	hdr->mem_size = mem_size;
-	hdr->rmem_size = mem_size;
-	hdr->mem_end = sys_info.mem_size;
-	hdr->num_pages = mem_size / PAGE_SIZE;
-	hdr->tod = get_tod_clock();
-	get_cpu_id(&hdr->cpu_id);
-	for (i = 0; i < dump_save_areas.count; i++) {
-		prefix = dump_save_areas.areas[i]->sa.pref_reg;
-		hdr->real_cpu_cnt++;
-		if (!prefix)
-			continue;
-		hdr->lc_vec[hdr->cpu_cnt] = prefix;
-		hdr->cpu_cnt++;
-	}
-}
-
 /*
  * Provide IPL parameter information block from either HSA or memory
  * for future reipl
@@ -671,11 +308,9 @@ static int __init zcore_reipl_init(void)
 
 static int __init zcore_init(void)
 {
-	unsigned long mem_size, mem_end;
 	unsigned char arch;
 	int rc;
 
-	mem_size = mem_end = 0;
 	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
 		return -ENODATA;
 	if (OLDMEM_BASE)
@@ -709,15 +344,11 @@ static int __init zcore_init(void)
 		goto fail;
 	}
 
-	rc = get_mem_info(&mem_size, &mem_end);
+	pr_alert("DETECTED 'S390X (64 bit) OS'\n");
+	rc = init_cpu_info();
 	if (rc)
 		goto fail;
 
-	rc = sys_info_init(arch, mem_end);
-	if (rc)
-		goto fail;
-	zcore_header_init(arch, &zcore_header, mem_size);
-
 	rc = zcore_reipl_init();
 	if (rc)
 		goto fail;
@@ -727,17 +358,11 @@ static int __init zcore_init(void)
 		rc = -ENOMEM;
 		goto fail;
 	}
-	zcore_file = debugfs_create_file("mem", S_IRUSR, zcore_dir, NULL,
-					 &zcore_fops);
-	if (!zcore_file) {
-		rc = -ENOMEM;
-		goto fail_dir;
-	}
 	zcore_memmap_file = debugfs_create_file("memmap", S_IRUSR, zcore_dir,
 						NULL, &zcore_memmap_fops);
 	if (!zcore_memmap_file) {
 		rc = -ENOMEM;
-		goto fail_file;
+		goto fail_dir;
 	}
 	zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 						NULL, &zcore_reipl_fops);
@@ -757,8 +382,6 @@ fail_reipl_file:
 	debugfs_remove(zcore_reipl_file);
 fail_memmap_file:
 	debugfs_remove(zcore_memmap_file);
-fail_file:
-	debugfs_remove(zcore_file);
 fail_dir:
 	debugfs_remove(zcore_dir);
 fail:
@@ -774,7 +397,6 @@ static void __exit zcore_exit(void)
 	debugfs_remove(zcore_hsa_file);
 	debugfs_remove(zcore_reipl_file);
 	debugfs_remove(zcore_memmap_file);
-	debugfs_remove(zcore_file);
 	debugfs_remove(zcore_dir);
 	diag308(DIAG308_REL_HSA, NULL);
 }