// SPDX-License-Identifier: GPL-2.0
/*
 *    Hypervisor filesystem for Linux on s390. Diag 204 and 224
 *    implementation.
 *
 *    Copyright IBM Corp. 2006, 2008
 *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
 */

#define pr_fmt(fmt) "hypfs: " fmt

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <asm/machine.h>
#include <asm/diag.h>
#include <asm/ebcdic.h>
#include "hypfs_diag.h"
#include "hypfs.h"

#define TMP_SIZE 64		/* size of temporary buffers */

static char *diag224_cpu_names;			/* diag 224 name table */
static int diag224_idx2name(int index, char *name);

/*
 * DIAG 204 member access functions.
 *
 * Since we have two different diag 204 data formats for old and new s390
 * machines, we do not access the structs directly, but use getter functions for
 * each struct member instead. This should make the code more readable.
 */

/* Time information block */

static inline int info_blk_hdr__size(enum diag204_format type)
{
	if (type == DIAG204_INFO_SIMPLE)
		return sizeof(struct diag204_info_blk_hdr);
	else /* DIAG204_INFO_EXT */
		return sizeof(struct diag204_x_info_blk_hdr);
}

static inline __u8 info_blk_hdr__npar(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_info_blk_hdr *)hdr)->npar;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_info_blk_hdr *)hdr)->npar;
}

static inline __u8 info_blk_hdr__flags(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_info_blk_hdr *)hdr)->flags;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_info_blk_hdr *)hdr)->flags;
}

/* Partition header */

static inline int part_hdr__size(enum diag204_format type)
{
	if (type == DIAG204_INFO_SIMPLE)
		return sizeof(struct diag204_part_hdr);
	else /* DIAG204_INFO_EXT */
		return sizeof(struct diag204_x_part_hdr);
}

static inline __u8 part_hdr__rcpus(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_part_hdr *)hdr)->cpus;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_part_hdr *)hdr)->rcpus;
}

static inline void part_hdr__part_name(enum diag204_format type, void *hdr,
				       char *name)
{
	if (type == DIAG204_INFO_SIMPLE)
		memcpy(name, ((struct diag204_part_hdr *)hdr)->part_name,
		       DIAG204_LPAR_NAME_LEN);
	else /* DIAG204_INFO_EXT */
		memcpy(name, ((struct diag204_x_part_hdr *)hdr)->part_name,
		       DIAG204_LPAR_NAME_LEN);
	EBCASC(name, DIAG204_LPAR_NAME_LEN);
	name[DIAG204_LPAR_NAME_LEN] = 0;
	strim(name);
}

/* CPU info block */

static inline int cpu_info__size(enum diag204_format type)
{
	if (type == DIAG204_INFO_SIMPLE)
		return sizeof(struct diag204_cpu_info);
	else /* DIAG204_INFO_EXT */
		return sizeof(struct diag204_x_cpu_info);
}

static inline __u8 cpu_info__ctidx(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_cpu_info *)hdr)->ctidx;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_cpu_info *)hdr)->ctidx;
}

static inline __u16 cpu_info__cpu_addr(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_cpu_info *)hdr)->cpu_addr;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_cpu_info *)hdr)->cpu_addr;
}

static inline __u64 cpu_info__acc_time(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_cpu_info *)hdr)->acc_time;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_cpu_info *)hdr)->acc_time;
}

static inline __u64 cpu_info__lp_time(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_cpu_info *)hdr)->lp_time;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_cpu_info *)hdr)->lp_time;
}

static inline __u64 cpu_info__online_time(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return 0;	/* online_time not available in simple info */
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_cpu_info *)hdr)->online_time;
}

/* Physical header */

static inline int phys_hdr__size(enum diag204_format type)
{
	if (type == DIAG204_INFO_SIMPLE)
		return sizeof(struct diag204_phys_hdr);
	else /* DIAG204_INFO_EXT */
		return sizeof(struct diag204_x_phys_hdr);
}

static inline __u8 phys_hdr__cpus(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_phys_hdr *)hdr)->cpus;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_phys_hdr *)hdr)->cpus;
}

/* Physical CPU info block */

static inline int phys_cpu__size(enum diag204_format type)
{
	if (type == DIAG204_INFO_SIMPLE)
		return sizeof(struct diag204_phys_cpu);
	else /* DIAG204_INFO_EXT */
		return sizeof(struct diag204_x_phys_cpu);
}

static inline __u16 phys_cpu__cpu_addr(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_phys_cpu *)hdr)->cpu_addr;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_phys_cpu *)hdr)->cpu_addr;
}

static inline __u64 phys_cpu__mgm_time(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_phys_cpu *)hdr)->mgm_time;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_phys_cpu *)hdr)->mgm_time;
}

static inline __u64 phys_cpu__ctidx(enum diag204_format type, void *hdr)
{
	if (type == DIAG204_INFO_SIMPLE)
		return ((struct diag204_phys_cpu *)hdr)->ctidx;
	else /* DIAG204_INFO_EXT */
		return ((struct diag204_x_phys_cpu *)hdr)->ctidx;
}

/*
 * Functions to create the directory structure
 * *******************************************
 */

static int hypfs_create_cpu_files(struct dentry *cpus_dir, void *cpu_info)
{
	struct dentry *cpu_dir;
	char buffer[TMP_SIZE];
	int rc;

	snprintf(buffer, TMP_SIZE, "%d", cpu_info__cpu_addr(diag204_get_info_type(),
							    cpu_info));
	cpu_dir = hypfs_mkdir(cpus_dir, buffer);
	if (IS_ERR(cpu_dir))
		return PTR_ERR(cpu_dir);
	rc = hypfs_create_u64(cpu_dir, "mgmtime",
			      cpu_info__acc_time(diag204_get_info_type(), cpu_info) -
			      cpu_info__lp_time(diag204_get_info_type(), cpu_info));
	if (rc)
		return rc;
	rc = hypfs_create_u64(cpu_dir, "cputime",
			      cpu_info__lp_time(diag204_get_info_type(), cpu_info));
	if (rc)
		return rc;
	if (diag204_get_info_type() == DIAG204_INFO_EXT) {
		rc = hypfs_create_u64(cpu_dir, "onlinetime",
				      cpu_info__online_time(diag204_get_info_type(),
							    cpu_info));
		if (rc)
			return rc;
	}
	diag224_idx2name(cpu_info__ctidx(diag204_get_info_type(), cpu_info), buffer);
	return hypfs_create_str(cpu_dir, "type", buffer);
}

static void *hypfs_create_lpar_files(struct dentry *systems_dir, void *part_hdr)
{
	struct dentry *cpus_dir;
	struct dentry *lpar_dir;
	char lpar_name[DIAG204_LPAR_NAME_LEN + 1];
	void *cpu_info;
	int i;

	part_hdr__part_name(diag204_get_info_type(), part_hdr, lpar_name);
	lpar_name[DIAG204_LPAR_NAME_LEN] = 0;
	lpar_dir = hypfs_mkdir(systems_dir, lpar_name);
	if (IS_ERR(lpar_dir))
		return lpar_dir;
	cpus_dir = hypfs_mkdir(lpar_dir, "cpus");
	if (IS_ERR(cpus_dir))
		return cpus_dir;
	cpu_info = part_hdr + part_hdr__size(diag204_get_info_type());
	for (i = 0; i < part_hdr__rcpus(diag204_get_info_type(), part_hdr); i++) {
		int rc;

		rc = hypfs_create_cpu_files(cpus_dir, cpu_info);
		if (rc)
			return ERR_PTR(rc);
		cpu_info += cpu_info__size(diag204_get_info_type());
	}
	return cpu_info;
}

static int hypfs_create_phys_cpu_files(struct dentry *cpus_dir, void *cpu_info)
{
	struct dentry *cpu_dir;
	char buffer[TMP_SIZE];
	int rc;

	snprintf(buffer, TMP_SIZE, "%i", phys_cpu__cpu_addr(diag204_get_info_type(),
							    cpu_info));
	cpu_dir = hypfs_mkdir(cpus_dir, buffer);
	if (IS_ERR(cpu_dir))
		return PTR_ERR(cpu_dir);
	rc = hypfs_create_u64(cpu_dir, "mgmtime",
			      phys_cpu__mgm_time(diag204_get_info_type(), cpu_info));
	if (rc)
		return rc;
	diag224_idx2name(phys_cpu__ctidx(diag204_get_info_type(), cpu_info), buffer);
	return hypfs_create_str(cpu_dir, "type", buffer);
}

static void *hypfs_create_phys_files(struct dentry *parent_dir, void *phys_hdr)
{
	int i;
	void *cpu_info;
	struct dentry *cpus_dir;

	cpus_dir = hypfs_mkdir(parent_dir, "cpus");
	if (IS_ERR(cpus_dir))
		return cpus_dir;
	cpu_info = phys_hdr + phys_hdr__size(diag204_get_info_type());
	for (i = 0; i < phys_hdr__cpus(diag204_get_info_type(), phys_hdr); i++) {
		int rc;

		rc = hypfs_create_phys_cpu_files(cpus_dir, cpu_info);
		if (rc)
			return ERR_PTR(rc);
		cpu_info += phys_cpu__size(diag204_get_info_type());
	}
	return cpu_info;
}

int hypfs_diag_create_files(struct dentry *root)
{
	struct dentry *systems_dir, *hyp_dir;
	void *time_hdr, *part_hdr;
	void *buffer, *ptr;
	int i, rc, pages;

	buffer = diag204_get_buffer(diag204_get_info_type(), &pages);
	if (IS_ERR(buffer))
		return PTR_ERR(buffer);
	rc = diag204_store(buffer, pages);
	if (rc)
		return rc;

	systems_dir = hypfs_mkdir(root, "systems");
	if (IS_ERR(systems_dir))
		return PTR_ERR(systems_dir);
	time_hdr = (struct x_info_blk_hdr *)buffer;
	part_hdr = time_hdr + info_blk_hdr__size(diag204_get_info_type());
	for (i = 0; i < info_blk_hdr__npar(diag204_get_info_type(), time_hdr); i++) {
		part_hdr = hypfs_create_lpar_files(systems_dir, part_hdr);
		if (IS_ERR(part_hdr))
			return PTR_ERR(part_hdr);
	}
	if (info_blk_hdr__flags(diag204_get_info_type(), time_hdr) &
	    DIAG204_LPAR_PHYS_FLG) {
		ptr = hypfs_create_phys_files(root, part_hdr);
		if (IS_ERR(ptr))
			return PTR_ERR(ptr);
	}
	hyp_dir = hypfs_mkdir(root, "hyp");
	if (IS_ERR(hyp_dir))
		return PTR_ERR(hyp_dir);
	return hypfs_create_str(hyp_dir, "type", "LPAR Hypervisor");
}

/* Diagnose 224 functions */

static int diag224_idx2name(int index, char *name)
{
	memcpy(name, diag224_cpu_names + ((index + 1) * DIAG204_CPU_NAME_LEN),
	       DIAG204_CPU_NAME_LEN);
	name[DIAG204_CPU_NAME_LEN] = 0;
	strim(name);
	return 0;
}

static int diag224_get_name_table(void)
{
	/* memory must be below 2GB */
	diag224_cpu_names = (char *)__get_free_page(GFP_KERNEL | GFP_DMA);
	if (!diag224_cpu_names)
		return -ENOMEM;
	if (diag224(diag224_cpu_names)) {
		free_page((unsigned long)diag224_cpu_names);
		return -EOPNOTSUPP;
	}
	EBCASC(diag224_cpu_names + 16, (*diag224_cpu_names + 1) * 16);
	return 0;
}

static void diag224_delete_name_table(void)
{
	free_page((unsigned long)diag224_cpu_names);
}

int __init __hypfs_diag_fs_init(void)
{
	if (machine_is_lpar())
		return diag224_get_name_table();
	return 0;
}

void __hypfs_diag_fs_exit(void)
{
	diag224_delete_name_table();
}
