summaryrefslogtreecommitdiff
path: root/arch/nds32/kernel/vdso.c
blob: 016f15891f6d40c22a908a6da6c719c5a3c6503a (plain)
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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2012 ARM Limited
// Copyright (C) 2005-2017 Andes Technology Corporation

#include <linux/cache.h>
#include <linux/clocksource.h>
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/slab.h>
#include <linux/timekeeper_internal.h>
#include <linux/vmalloc.h>
#include <linux/random.h>

#include <asm/cacheflush.h>
#include <asm/vdso.h>
#include <asm/vdso_datapage.h>
#include <asm/vdso_timer_info.h>
#include <asm/cache_info.h>
extern struct cache_info L1_cache_info[2];
extern char vdso_start[], vdso_end[];
static unsigned long vdso_pages __ro_after_init;
static unsigned long timer_mapping_base;

struct timer_info_t timer_info = {
	.cycle_count_down = true,
	.mapping_base = EMPTY_TIMER_MAPPING,
	.cycle_count_reg_offset = EMPTY_REG_OFFSET
};
/*
 * The vDSO data page.
 */
static struct page *no_pages[] = { NULL };

static union {
	struct vdso_data data;
	u8 page[PAGE_SIZE];
} vdso_data_store __page_aligned_data;
struct vdso_data *vdso_data = &vdso_data_store.data;
static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
	{
	 .name = "[vvar]",
	 .pages = no_pages,
	 },
	{
	 .name = "[vdso]",
	 },
};

static void get_timer_node_info(void)
{
	timer_mapping_base = timer_info.mapping_base;
	vdso_data->cycle_count_offset =
		timer_info.cycle_count_reg_offset;
	vdso_data->cycle_count_down =
		timer_info.cycle_count_down;
}

static int __init vdso_init(void)
{
	int i;
	struct page **vdso_pagelist;

	if (memcmp(vdso_start, "\177ELF", 4)) {
		pr_err("vDSO is not a valid ELF object!\n");
		return -EINVAL;
	}
	/* Creat a timer io mapping to get clock cycles counter */
	get_timer_node_info();

	vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
	pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
		vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data);

	/* Allocate the vDSO pagelist */
	vdso_pagelist = kcalloc(vdso_pages, sizeof(struct page *), GFP_KERNEL);
	if (vdso_pagelist == NULL)
		return -ENOMEM;

	for (i = 0; i < vdso_pages; i++)
		vdso_pagelist[i] = virt_to_page(vdso_start + i * PAGE_SIZE);
	vdso_spec[1].pages = &vdso_pagelist[0];

	return 0;
}

arch_initcall(vdso_init);

unsigned long inline vdso_random_addr(unsigned long vdso_mapping_len)
{
	unsigned long start = current->mm->mmap_base, end, offset, addr;
	start = PAGE_ALIGN(start);

	/* Round the lowest possible end address up to a PMD boundary. */
	end = (start + vdso_mapping_len + PMD_SIZE - 1) & PMD_MASK;
	if (end >= TASK_SIZE)
		end = TASK_SIZE;
	end -= vdso_mapping_len;

	if (end > start) {
		offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
		addr = start + (offset << PAGE_SHIFT);
	} else {
		addr = start;
	}
	return addr;
}

int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
	struct mm_struct *mm = current->mm;
	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
	struct vm_area_struct *vma;
	unsigned long addr = 0;
	pgprot_t prot;
	int ret, vvar_page_num = 2;

	vdso_text_len = vdso_pages << PAGE_SHIFT;

	if(timer_mapping_base == EMPTY_VALUE)
		vvar_page_num = 1;
	/* Be sure to map the data page */
	vdso_mapping_len = vdso_text_len + vvar_page_num * PAGE_SIZE;
#ifdef CONFIG_CPU_CACHE_ALIASING
	vdso_mapping_len += L1_cache_info[DCACHE].aliasing_num - 1;
#endif

	if (down_write_killable(&mm->mmap_sem))
		return -EINTR;

	addr = vdso_random_addr(vdso_mapping_len);
	vdso_base = get_unmapped_area(NULL, addr, vdso_mapping_len, 0, 0);
	if (IS_ERR_VALUE(vdso_base)) {
		ret = vdso_base;
		goto up_fail;
	}

#ifdef CONFIG_CPU_CACHE_ALIASING
	{
		unsigned int aliasing_mask =
		    L1_cache_info[DCACHE].aliasing_mask;
		unsigned int page_colour_ofs;
		page_colour_ofs = ((unsigned int)vdso_data & aliasing_mask) -
		    (vdso_base & aliasing_mask);
		vdso_base += page_colour_ofs & aliasing_mask;
	}
#endif

	vma = _install_special_mapping(mm, vdso_base, vvar_page_num * PAGE_SIZE,
				       VM_READ | VM_MAYREAD, &vdso_spec[0]);
	if (IS_ERR(vma)) {
		ret = PTR_ERR(vma);
		goto up_fail;
	}

	/*Map vdata to user space */
	ret = io_remap_pfn_range(vma, vdso_base,
				 virt_to_phys(vdso_data) >> PAGE_SHIFT,
				 PAGE_SIZE, vma->vm_page_prot);
	if (ret)
		goto up_fail;

	/*Map timer to user space */
	vdso_base += PAGE_SIZE;
	prot = __pgprot(_PAGE_V | _PAGE_M_UR_KR | _PAGE_D |  _PAGE_C_DEV);
	ret = io_remap_pfn_range(vma, vdso_base, timer_mapping_base >> PAGE_SHIFT,
				 PAGE_SIZE, prot);
	if (ret)
		goto up_fail;

	/*Map vdso to user space */
	vdso_base += PAGE_SIZE;
	mm->context.vdso = (void *)vdso_base;
	vma = _install_special_mapping(mm, vdso_base, vdso_text_len,
				       VM_READ | VM_EXEC |
				       VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
				       &vdso_spec[1]);
	if (IS_ERR(vma)) {
		ret = PTR_ERR(vma);
		goto up_fail;
	}

	up_write(&mm->mmap_sem);
	return 0;

up_fail:
	mm->context.vdso = NULL;
	up_write(&mm->mmap_sem);
	return ret;
}

static void vdso_write_begin(struct vdso_data *vdata)
{
	++vdso_data->seq_count;
	smp_wmb();		/* Pairs with smp_rmb in vdso_read_retry */
}

static void vdso_write_end(struct vdso_data *vdata)
{
	smp_wmb();		/* Pairs with smp_rmb in vdso_read_begin */
	++vdso_data->seq_count;
}

void update_vsyscall(struct timekeeper *tk)
{
	vdso_write_begin(vdso_data);
	vdso_data->cs_mask = tk->tkr_mono.mask;
	vdso_data->cs_mult = tk->tkr_mono.mult;
	vdso_data->cs_shift = tk->tkr_mono.shift;
	vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
	vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
	vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
	vdso_data->xtime_clock_sec = tk->xtime_sec;
	vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
	vdso_data->xtime_coarse_sec = tk->xtime_sec;
	vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >>
	    tk->tkr_mono.shift;
	vdso_write_end(vdso_data);
}

void update_vsyscall_tz(void)
{
	vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
	vdso_data->tz_dsttime = sys_tz.tz_dsttime;
}