// SPDX-License-Identifier: GPL-2.0/* * Privileged ADI driver for sparc64 * * Author: Tom Hromatka <tom.hromatka@oracle.com> */#include <linux/kernel.h>#include <linux/miscdevice.h>#include <linux/module.h>#include <linux/proc_fs.h>#include <linux/slab.h>#include <linux/uaccess.h>#include <asm/asi.h> #define MAX_BUF_SZ	PAGE_SIZE static int read_mcd_tag(unsigned long addr){	long err;	int ver; 	__asm__ __volatile__(		"1:	ldxa [%[addr]] %[asi], %[ver]\n"		"	mov 0, %[err]\n"		"2:\n"		"	.section .fixup,#alloc,#execinstr\n"		"	.align 4\n"		"3:	sethi %%hi(2b), %%g1\n"		"	jmpl  %%g1 + %%lo(2b), %%g0\n"		"	mov %[invalid], %[err]\n"		"	.previous\n"		"	.section __ex_table, \"a\"\n"		"	.align 4\n"		"	.word  1b, 3b\n"		"	.previous\n"		: [ver] "=r" (ver), [err] "=r" (err)		: [addr] "r"  (addr), [invalid] "i" (EFAULT),		  [asi] "i" (ASI_MCD_REAL)		: "memory", "g1"		); 	if (err)		return -EFAULT;	else		return ver;} static ssize_t adi_read(struct file *file, char __user *buf,			size_t count, loff_t *offp){	size_t ver_buf_sz, bytes_read = 0;	int ver_buf_idx = 0;	loff_t offset;	u8 *ver_buf;	ssize_t ret; 	ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);	ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);	if (!ver_buf)		return -ENOMEM; 	offset = (*offp) * adi_blksize(); 	while (bytes_read < count) {		ret = read_mcd_tag(offset);		if (ret < 0)			goto out; 		ver_buf[ver_buf_idx] = (u8)ret;		ver_buf_idx++;		offset += adi_blksize(); 		if (ver_buf_idx >= ver_buf_sz) {			if (copy_to_user(buf + bytes_read, ver_buf,					 ver_buf_sz)) {				ret = -EFAULT;				goto out;			} 			bytes_read += ver_buf_sz;			ver_buf_idx = 0; 			ver_buf_sz = min_t(size_t, count - bytes_read,					   MAX_BUF_SZ);		}	} 	(*offp) += bytes_read;	ret = bytes_read;out:	kfree(ver_buf);	return ret;} static int set_mcd_tag(unsigned long addr, u8 ver){	long err; 	__asm__ __volatile__(		"1:	stxa %[ver], [%[addr]] %[asi]\n"		"	mov 0, %[err]\n"		"2:\n"		"	.section .fixup,#alloc,#execinstr\n"		"	.align 4\n"		"3:	sethi %%hi(2b), %%g1\n"		"	jmpl %%g1 + %%lo(2b), %%g0\n"		"	mov %[invalid], %[err]\n"		"	.previous\n"		"	.section __ex_table, \"a\"\n"		"	.align 4\n"		"	.word 1b, 3b\n"		"	.previous\n"		: [err] "=r" (err)		: [ver] "r" (ver), [addr] "r"  (addr),		  [invalid] "i" (EFAULT), [asi] "i" (ASI_MCD_REAL)		: "memory", "g1"		); 	if (err)		return -EFAULT;	else		return ver;} static ssize_t adi_write(struct file *file, const char __user *buf,			 size_t count, loff_t *offp){	size_t ver_buf_sz, bytes_written = 0;	loff_t offset;	u8 *ver_buf;	ssize_t ret;	int i; 	if (count == 0)		return -EINVAL; 	ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);	ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);	if (!ver_buf)		return -ENOMEM; 	offset = (*offp) * adi_blksize(); 	do {		if (copy_from_user(ver_buf, &buf[bytes_written],				   ver_buf_sz)) {			ret = -EFAULT;			goto out;		} 		for (i = 0; i < ver_buf_sz; i++) {			ret = set_mcd_tag(offset, ver_buf[i]);			if (ret < 0)				goto out; 			offset += adi_blksize();		} 		bytes_written += ver_buf_sz;		ver_buf_sz = min_t(size_t, count - bytes_written, MAX_BUF_SZ);	} while (bytes_written < count); 	(*offp) += bytes_written;	ret = bytes_written;out:	__asm__ __volatile__("membar #Sync");	kfree(ver_buf);	return ret;} static loff_t adi_llseek(struct file *file, loff_t offset, int whence){	loff_t ret = -EINVAL; 	switch (whence) {	case SEEK_END:	case SEEK_DATA:	case SEEK_HOLE:		/* unsupported */		return -EINVAL;	case SEEK_CUR:		if (offset == 0)			return file->f_pos; 		offset += file->f_pos;		break;	case SEEK_SET:		break;	} 	if (offset != file->f_pos) {		file->f_pos = offset;		ret = offset;	} 	return ret;} static const struct file_operations adi_fops = {	.owner		= THIS_MODULE,	.llseek		= adi_llseek,	.read		= adi_read,	.write		= adi_write,	.fop_flags	= FOP_UNSIGNED_OFFSET,}; static struct miscdevice adi_miscdev = {	.minor = MISC_DYNAMIC_MINOR,	.name = KBUILD_MODNAME,	.fops = &adi_fops,}; static int __init adi_init(void){	if (!adi_capable())		return -EPERM; 	return misc_register(&adi_miscdev);} static void __exit adi_exit(void){	misc_deregister(&adi_miscdev);} module_init(adi_init);module_exit(adi_exit); MODULE_AUTHOR("Tom Hromatka <tom.hromatka@oracle.com>");MODULE_DESCRIPTION("Privileged interface to ADI");MODULE_VERSION("1.0");MODULE_LICENSE("GPL v2");