1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/init.h>
3 #include <linux/seq_file.h>
4 #include <linux/fs.h>
5 #include <linux/mm.h>
6 #include <linux/proc_fs.h>
7 #include <linux/slab.h>
8 #include <xen/interface/platform.h>
9 #include <asm/xen/hypercall.h>
10 #include <xen/xen-ops.h>
11 #include "xenfs.h"
12
13
14 #define XEN_KSYM_NAME_LEN 127 /* Hypervisor may have different name length */
15
16 struct xensyms {
17 struct xen_platform_op op;
18 char *name;
19 uint32_t namelen;
20 };
21
22 /* Grab next output page from the hypervisor */
xensyms_next_sym(struct xensyms * xs)23 static int xensyms_next_sym(struct xensyms *xs)
24 {
25 int ret;
26 struct xenpf_symdata *symdata = &xs->op.u.symdata;
27 uint64_t symnum;
28
29 memset(xs->name, 0, xs->namelen);
30 symdata->namelen = xs->namelen;
31
32 symnum = symdata->symnum;
33
34 ret = HYPERVISOR_platform_op(&xs->op);
35 if (ret < 0)
36 return ret;
37
38 /*
39 * If hypervisor's symbol didn't fit into the buffer then allocate
40 * a larger buffer and try again.
41 */
42 if (unlikely(symdata->namelen > xs->namelen)) {
43 kfree(xs->name);
44
45 xs->namelen = symdata->namelen;
46 xs->name = kzalloc(xs->namelen, GFP_KERNEL);
47 if (!xs->name)
48 return -ENOMEM;
49
50 set_xen_guest_handle(symdata->name, xs->name);
51 symdata->symnum--; /* Rewind */
52
53 ret = HYPERVISOR_platform_op(&xs->op);
54 if (ret < 0)
55 return ret;
56 }
57
58 if (symdata->symnum == symnum)
59 /* End of symbols */
60 return 1;
61
62 return 0;
63 }
64
xensyms_start(struct seq_file * m,loff_t * pos)65 static void *xensyms_start(struct seq_file *m, loff_t *pos)
66 {
67 struct xensyms *xs = m->private;
68
69 xs->op.u.symdata.symnum = *pos;
70
71 if (xensyms_next_sym(xs))
72 return NULL;
73
74 return m->private;
75 }
76
xensyms_next(struct seq_file * m,void * p,loff_t * pos)77 static void *xensyms_next(struct seq_file *m, void *p, loff_t *pos)
78 {
79 struct xensyms *xs = m->private;
80
81 xs->op.u.symdata.symnum = ++(*pos);
82
83 if (xensyms_next_sym(xs))
84 return NULL;
85
86 return p;
87 }
88
xensyms_show(struct seq_file * m,void * p)89 static int xensyms_show(struct seq_file *m, void *p)
90 {
91 struct xensyms *xs = m->private;
92 struct xenpf_symdata *symdata = &xs->op.u.symdata;
93
94 seq_printf(m, "%016llx %c %s\n", symdata->address,
95 symdata->type, xs->name);
96
97 return 0;
98 }
99
xensyms_stop(struct seq_file * m,void * p)100 static void xensyms_stop(struct seq_file *m, void *p)
101 {
102 }
103
104 static const struct seq_operations xensyms_seq_ops = {
105 .start = xensyms_start,
106 .next = xensyms_next,
107 .show = xensyms_show,
108 .stop = xensyms_stop,
109 };
110
xensyms_open(struct inode * inode,struct file * file)111 static int xensyms_open(struct inode *inode, struct file *file)
112 {
113 struct seq_file *m;
114 struct xensyms *xs;
115 int ret;
116
117 ret = seq_open_private(file, &xensyms_seq_ops,
118 sizeof(struct xensyms));
119 if (ret)
120 return ret;
121
122 m = file->private_data;
123 xs = m->private;
124
125 xs->namelen = XEN_KSYM_NAME_LEN + 1;
126 xs->name = kzalloc(xs->namelen, GFP_KERNEL);
127 if (!xs->name) {
128 seq_release_private(inode, file);
129 return -ENOMEM;
130 }
131 set_xen_guest_handle(xs->op.u.symdata.name, xs->name);
132 xs->op.cmd = XENPF_get_symbol;
133 xs->op.u.symdata.namelen = xs->namelen;
134
135 return 0;
136 }
137
xensyms_release(struct inode * inode,struct file * file)138 static int xensyms_release(struct inode *inode, struct file *file)
139 {
140 struct seq_file *m = file->private_data;
141 struct xensyms *xs = m->private;
142
143 kfree(xs->name);
144 return seq_release_private(inode, file);
145 }
146
147 const struct file_operations xensyms_ops = {
148 .open = xensyms_open,
149 .read = seq_read,
150 .llseek = seq_lseek,
151 .release = xensyms_release
152 };
153