zcore.c

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/*
 * 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>
#include "sclp.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(0xf8UL); /* 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), "=m" (*((long*)dest))
		: "m" (*((long*)src))
		: "cc", "memory");
	__raw_local_irq_ssm(flags);

	return rc;
}

static int memcpy_real_user(void __user *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 volnr;
	u32 build_arch;
	u64 rmem_size;
	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;