jailhouse_dbgcon.c
2.2 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Console driver for running over the Jailhouse partitioning hypervisor
*
* Copyright (c) Siemens AG, 2016-2018
*
* Authors:
* Jan Kiszka <jan.kiszka@siemens.com>
*/
#include <linux/console.h>
#include <linux/hypervisor.h>
#include <linux/module.h>
#include <linux/serial_core.h>
#ifdef CONFIG_X86
#include <asm/alternative.h>
#endif
#ifdef CONFIG_ARM
#include <asm/opcodes-virt.h>
#endif
#define JAILHOUSE_HC_DEBUG_CONSOLE_PUTC 8
static void hypervisor_putc(char c)
{
#if defined(CONFIG_X86)
int result;
asm volatile(
ALTERNATIVE(".byte 0x0f,0x01,0xc1", ".byte 0x0f,0x01,0xd9",
X86_FEATURE_VMMCALL)
: "=a" (result)
: "a" (JAILHOUSE_HC_DEBUG_CONSOLE_PUTC), "D" (c)
: "memory");
#elif defined(CONFIG_ARM)
register u32 num_res asm("r0") = JAILHOUSE_HC_DEBUG_CONSOLE_PUTC;
register u32 arg1 asm("r1") = c;
asm volatile(
__HVC(0x4a48)
: "=r" (num_res)
: "r" (num_res), "r" (arg1)
: "memory");
#elif defined(CONFIG_ARM64)
register u64 num_res asm("x0") = JAILHOUSE_HC_DEBUG_CONSOLE_PUTC;
register u64 arg1 asm("x1") = c;
asm volatile(
"hvc #0x4a48\n\t"
: "=r" (num_res)
: "r" (num_res), "r" (arg1)
: "memory");
#else
#error Unsupported architecture.
#endif
}
static void jailhouse_dbgcon_write(struct console *con, const char *s,
unsigned count)
{
while (count > 0) {
hypervisor_putc(*s);
count--;
s++;
}
}
static int __init early_jailhouse_dbgcon_setup(struct earlycon_device *device,
const char *options)
{
device->con->write = jailhouse_dbgcon_write;
return 0;
}
EARLYCON_DECLARE(jailhouse, early_jailhouse_dbgcon_setup);
static struct console jailhouse_dbgcon = {
.name = "jailhouse",
.write = jailhouse_dbgcon_write,
.flags = CON_PRINTBUFFER | CON_ANYTIME,
.index = -1,
};
static int __init jailhouse_dbgcon_init(void)
{
if (!jailhouse_paravirt())
return -ENODEV;
register_console(&jailhouse_dbgcon);
return 0;
}
static void __exit jailhouse_dbgcon_exit(void)
{
unregister_console(&jailhouse_dbgcon);
}
module_init(jailhouse_dbgcon_init);
module_exit(jailhouse_dbgcon_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Jailhouse debug console driver");
MODULE_AUTHOR("Jan Kiszka <jan.kiszka@siemens.com>");