[deliverable/linux.git] / arch / arm64 / kernel / vdso.c

/*
 * VDSO implementation for AArch64 and vector page setup for AArch32.
 *
 * Copyright (C) 2012 ARM Limited
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */

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

#include <asm/cacheflush.h>
#include <asm/signal32.h>
#include <asm/vdso.h>
#include <asm/vdso_datapage.h>

extern char vdso_start, vdso_end;
static unsigned long vdso_pages;
static struct page **vdso_pagelist;

/*
 * The vDSO data page.
 */
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;

#ifdef CONFIG_COMPAT
/*
 * Create and map the vectors page for AArch32 tasks.
 */
static struct page *vectors_page[1];

static int alloc_vectors_page(void)
{
	extern char __kuser_helper_start[], __kuser_helper_end[];
	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
	unsigned long vpage;

	vpage = get_zeroed_page(GFP_ATOMIC);

	if (!vpage)
		return -ENOMEM;

	/* kuser helpers */
	memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
		kuser_sz);

	/* sigreturn code */
	memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
		aarch32_sigret_code, sizeof(aarch32_sigret_code));

	flush_icache_range(vpage, vpage + PAGE_SIZE);
	vectors_page[0] = virt_to_page(vpage);

	return 0;
}
arch_initcall(alloc_vectors_page);

int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
{
	struct mm_struct *mm = current->mm;
	unsigned long addr = AARCH32_VECTORS_BASE;
	int ret;

	down_write(&mm->mmap_sem);
	current->mm->context.vdso = (void *)addr;

	/* Map vectors page at the high address. */
	ret = install_special_mapping(mm, addr, PAGE_SIZE,
				      VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
				      vectors_page);

	up_write(&mm->mmap_sem);

	return ret;
}
#endif /* CONFIG_COMPAT */

static int __init vdso_init(void)
{
	struct page *pg;
	char *vbase;
	int i, ret = 0;

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

	/* Allocate the vDSO pagelist, plus a page for the data. */
	vdso_pagelist = kzalloc(sizeof(struct page *) * (vdso_pages + 1),
				GFP_KERNEL);
	if (vdso_pagelist == NULL) {
		pr_err("Failed to allocate vDSO pagelist!\n");
		return -ENOMEM;
	}

	/* Grab the vDSO code pages. */
	for (i = 0; i < vdso_pages; i++) {
		pg = virt_to_page(&vdso_start + i*PAGE_SIZE);
		ClearPageReserved(pg);
		get_page(pg);
		vdso_pagelist[i] = pg;
	}

	/* Sanity check the shared object header. */
	vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL);
	if (vbase == NULL) {
		pr_err("Failed to map vDSO pagelist!\n");
		return -ENOMEM;
	} else if (memcmp(vbase, "\177ELF", 4)) {
		pr_err("vDSO is not a valid ELF object!\n");
		ret = -EINVAL;
		goto unmap;
	}

	/* Grab the vDSO data page. */
	pg = virt_to_page(vdso_data);
	get_page(pg);
	vdso_pagelist[i] = pg;

unmap:
	vunmap(vbase);
	return ret;
}
arch_initcall(vdso_init);

int arch_setup_additional_pages(struct linux_binprm *bprm,
				int uses_interp)
{
	struct mm_struct *mm = current->mm;
	unsigned long vdso_base, vdso_mapping_len;
	int ret;

	/* Be sure to map the data page */
	vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT;

	down_write(&mm->mmap_sem);
	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
	if (IS_ERR_VALUE(vdso_base)) {
		ret = vdso_base;
		goto up_fail;
	}
	mm->context.vdso = (void *)vdso_base;

	ret = install_special_mapping(mm, vdso_base, vdso_mapping_len,
				      VM_READ|VM_EXEC|
				      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
				      vdso_pagelist);
	if (ret) {
		mm->context.vdso = NULL;
		goto up_fail;
	}

up_fail:
	up_write(&mm->mmap_sem);

	return ret;
}

const char *arch_vma_name(struct vm_area_struct *vma)
{
	/*
	 * We can re-use the vdso pointer in mm_context_t for identifying
	 * the vectors page for compat applications. The vDSO will always
	 * sit above TASK_UNMAPPED_BASE and so we don't need to worry about
	 * it conflicting with the vectors base.
	 */
	if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) {
#ifdef CONFIG_COMPAT
		if (vma->vm_start == AARCH32_VECTORS_BASE)
			return "[vectors]";
#endif
		return "[vdso]";
	}

	return NULL;
}

/*
 * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
 * Linux happy.
 */
int in_gate_area_no_mm(unsigned long addr)
{
	return 0;
}

int in_gate_area(struct mm_struct *mm, unsigned long addr)
{
	return 0;
}

struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
	return NULL;
}

/*
 * Update the vDSO data page to keep in sync with kernel timekeeping.
 */
void update_vsyscall(struct timespec *ts, struct timespec *wtm,
		     struct clocksource *clock, u32 mult)
{
	struct timespec xtime_coarse;
	u32 use_syscall = strcmp(clock->name, "arch_sys_counter");

	++vdso_data->tb_seq_count;
	smp_wmb();

	xtime_coarse = __current_kernel_time();
	vdso_data->use_syscall			= use_syscall;
	vdso_data->xtime_coarse_sec		= xtime_coarse.tv_sec;
	vdso_data->xtime_coarse_nsec		= xtime_coarse.tv_nsec;

	if (!use_syscall) {
		vdso_data->cs_cycle_last	= clock->cycle_last;
		vdso_data->xtime_clock_sec	= ts->tv_sec;
		vdso_data->xtime_clock_nsec	= ts->tv_nsec;
		vdso_data->cs_mult		= mult;
		vdso_data->cs_shift		= clock->shift;
		vdso_data->wtm_clock_sec	= wtm->tv_sec;
		vdso_data->wtm_clock_nsec	= wtm->tv_nsec;
	}

	smp_wmb();
	++vdso_data->tb_seq_count;
}

void update_vsyscall_tz(void)
{
	++vdso_data->tb_seq_count;
	smp_wmb();
	vdso_data->tz_minuteswest	= sys_tz.tz_minuteswest;
	vdso_data->tz_dsttime		= sys_tz.tz_dsttime;
	smp_wmb();
	++vdso_data->tb_seq_count;
}
Commit	Line	Data
9031fefd WD	1	/*
	2	* VDSO implementation for AArch64 and vector page setup for AArch32.
	3	*
	4	* Copyright (C) 2012 ARM Limited
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	*
	18	* Author: Will Deacon <will.deacon@arm.com>
	19	*/
	20
	21	#include <linux/kernel.h>
	22	#include <linux/clocksource.h>
	23	#include <linux/elf.h>
	24	#include <linux/err.h>
	25	#include <linux/errno.h>
	26	#include <linux/gfp.h>
	27	#include <linux/mm.h>
	28	#include <linux/sched.h>
	29	#include <linux/signal.h>
	30	#include <linux/slab.h>
	31	#include <linux/vmalloc.h>
	32
	33	#include <asm/cacheflush.h>
	34	#include <asm/signal32.h>
	35	#include <asm/vdso.h>
	36	#include <asm/vdso_datapage.h>
	37
	38	extern char vdso_start, vdso_end;
	39	static unsigned long vdso_pages;
	40	static struct page **vdso_pagelist;
	41
	42	/*
	43	* The vDSO data page.
	44	*/
	45	static union {
	46	struct vdso_data data;
	47	u8 page[PAGE_SIZE];
	48	} vdso_data_store __page_aligned_data;
	49	struct vdso_data *vdso_data = &vdso_data_store.data;
	50
	51	#ifdef CONFIG_COMPAT
	52	/*
	53	* Create and map the vectors page for AArch32 tasks.
	54	*/
	55	static struct page *vectors_page[1];
	56
	57	static int alloc_vectors_page(void)
	58	{
	59	extern char __kuser_helper_start[], __kuser_helper_end[];
	60	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
	61	unsigned long vpage;
	62
	63	vpage = get_zeroed_page(GFP_ATOMIC);
	64
65	if (!vpage)
66	return -ENOMEM;
67
68	/* kuser helpers */
69	memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
70	kuser_sz);
71
72	/* sigreturn code */
73	memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
74	aarch32_sigret_code, sizeof(aarch32_sigret_code));
75
76	flush_icache_range(vpage, vpage + PAGE_SIZE);
77	vectors_page[0] = virt_to_page(vpage);
78
79	return 0;
80	}
81	arch_initcall(alloc_vectors_page);
82
83	int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
84	{
85	struct mm_struct *mm = current->mm;
86	unsigned long addr = AARCH32_VECTORS_BASE;
87	int ret;
88
89	down_write(&mm->mmap_sem);
90	current->mm->context.vdso = (void *)addr;
91
92	/* Map vectors page at the high address. */
93	ret = install_special_mapping(mm, addr, PAGE_SIZE,
94	VM_READ\|VM_EXEC\|VM_MAYREAD\|VM_MAYEXEC,
95	vectors_page);
96
97	up_write(&mm->mmap_sem);
98
99	return ret;
100	}
101	#endif /* CONFIG_COMPAT */
102
103	static int __init vdso_init(void)
104	{
105	struct page *pg;
106	char *vbase;
107	int i, ret = 0;
108
109	vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
110	pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n",
111	vdso_pages + 1, vdso_pages, 1L, &vdso_start);
112
113	/* Allocate the vDSO pagelist, plus a page for the data. */
114	vdso_pagelist = kzalloc(sizeof(struct page ) (vdso_pages + 1),
115	GFP_KERNEL);
116	if (vdso_pagelist == NULL) {
117	pr_err("Failed to allocate vDSO pagelist!\n");
118	return -ENOMEM;
119	}
120
121	/* Grab the vDSO code pages. */
122	for (i = 0; i < vdso_pages; i++) {
123	pg = virt_to_page(&vdso_start + i*PAGE_SIZE);
124	ClearPageReserved(pg);
125	get_page(pg);
126	vdso_pagelist[i] = pg;
127	}
128
129	/* Sanity check the shared object header. */
130	vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL);
131	if (vbase == NULL) {
132	pr_err("Failed to map vDSO pagelist!\n");
133	return -ENOMEM;
134	} else if (memcmp(vbase, "\177ELF", 4)) {
135	pr_err("vDSO is not a valid ELF object!\n");
136	ret = -EINVAL;
137	goto unmap;
138	}
139
140	/* Grab the vDSO data page. */
141	pg = virt_to_page(vdso_data);
142	get_page(pg);
143	vdso_pagelist[i] = pg;
144
145	unmap:
146	vunmap(vbase);
147	return ret;
148	}
149	arch_initcall(vdso_init);
150
151	int arch_setup_additional_pages(struct linux_binprm *bprm,
152	int uses_interp)
153	{
154	struct mm_struct *mm = current->mm;
155	unsigned long vdso_base, vdso_mapping_len;
156	int ret;
157
158	/* Be sure to map the data page */
159	vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT;
160
161	down_write(&mm->mmap_sem);
162	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
163	if (IS_ERR_VALUE(vdso_base)) {
164	ret = vdso_base;
165	goto up_fail;
166	}
167	mm->context.vdso = (void *)vdso_base;
168
169	ret = install_special_mapping(mm, vdso_base, vdso_mapping_len,
170	VM_READ\|VM_EXEC\|
171	VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC,
172	vdso_pagelist);
173	if (ret) {
174	mm->context.vdso = NULL;
175	goto up_fail;
176	}
177
178	up_fail:
179	up_write(&mm->mmap_sem);
180
181	return ret;
182	}
183
184	const char arch_vma_name(struct vm_area_struct vma)
185	{
186	/*
187	* We can re-use the vdso pointer in mm_context_t for identifying
188	* the vectors page for compat applications. The vDSO will always
189	* sit above TASK_UNMAPPED_BASE and so we don't need to worry about
190	* it conflicting with the vectors base.
191	*/
192	if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) {
193	#ifdef CONFIG_COMPAT
194	if (vma->vm_start == AARCH32_VECTORS_BASE)
195	return "[vectors]";
196	#endif
197	return "[vdso]";
198	}
199
200	return NULL;
201	}
202
203	/*
204	* We define AT_SYSINFO_EHDR, so we need these function stubs to keep
205	* Linux happy.
206	*/
207	int in_gate_area_no_mm(unsigned long addr)
208	{
209	return 0;
210	}
211
212	int in_gate_area(struct mm_struct *mm, unsigned long addr)
213	{
214	return 0;
215	}
216
217	struct vm_area_struct get_gate_vma(struct mm_struct mm)
218	{
219	return NULL;
220	}
221
222	/*
223	* Update the vDSO data page to keep in sync with kernel timekeeping.
224	*/
225	void update_vsyscall(struct timespec ts, struct timespec wtm,
226	struct clocksource *clock, u32 mult)
227	{
228	struct timespec xtime_coarse;
229	u32 use_syscall = strcmp(clock->name, "arch_sys_counter");
230
231	++vdso_data->tb_seq_count;
232	smp_wmb();
233
234	xtime_coarse = __current_kernel_time();
235	vdso_data->use_syscall = use_syscall;
236	vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec;
237	vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec;
238
239	if (!use_syscall) {
240	vdso_data->cs_cycle_last = clock->cycle_last;
241	vdso_data->xtime_clock_sec = ts->tv_sec;
242	vdso_data->xtime_clock_nsec = ts->tv_nsec;
243	vdso_data->cs_mult = mult;
244	vdso_data->cs_shift = clock->shift;
245	vdso_data->wtm_clock_sec = wtm->tv_sec;
246	vdso_data->wtm_clock_nsec = wtm->tv_nsec;
247	}
248
249	smp_wmb();
250	++vdso_data->tb_seq_count;
251	}
252
253	void update_vsyscall_tz(void)
254	{
255	++vdso_data->tb_seq_count;
256	smp_wmb();
257	vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
258	vdso_data->tz_dsttime = sys_tz.tz_dsttime;
259	smp_wmb();
260	++vdso_data->tb_seq_count;
261	}