[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/timekeeper_internal.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[];
	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];

	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_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_start, sigret_sz);

	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 timekeeper *tk)
{
	struct timespec xtime_coarse;
	u32 use_syscall = strcmp(tk->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;
	vdso_data->wtm_clock_sec		= tk->wall_to_monotonic.tv_sec;
	vdso_data->wtm_clock_nsec		= tk->wall_to_monotonic.tv_nsec;

	if (!use_syscall) {
		vdso_data->cs_cycle_last	= tk->clock->cycle_last;
		vdso_data->xtime_clock_sec	= tk->xtime_sec;
		vdso_data->xtime_clock_nsec	= tk->xtime_nsec;
		vdso_data->cs_mult		= tk->mult;
		vdso_data->cs_shift		= tk->shift;
	}

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

void update_vsyscall_tz(void)
{
	vdso_data->tz_minuteswest	= sys_tz.tz_minuteswest;
	vdso_data->tz_dsttime		= sys_tz.tz_dsttime;
}
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>
c60b0c28	31	#include <linux/timekeeper_internal.h>
9031fefd WD	32	#include <linux/vmalloc.h>
	33
	34	#include <asm/cacheflush.h>
	35	#include <asm/signal32.h>
	36	#include <asm/vdso.h>
	37	#include <asm/vdso_datapage.h>
	38
	39	extern char vdso_start, vdso_end;
	40	static unsigned long vdso_pages;
	41	static struct page **vdso_pagelist;
	42
	43	/*
	44	* The vDSO data page.
	45	*/
	46	static union {
	47	struct vdso_data data;
	48	u8 page[PAGE_SIZE];
	49	} vdso_data_store __page_aligned_data;
	50	struct vdso_data *vdso_data = &vdso_data_store.data;
	51
	52	#ifdef CONFIG_COMPAT
	53	/*
	54	* Create and map the vectors page for AArch32 tasks.
	55	*/
	56	static struct page *vectors_page[1];
	57
	58	static int alloc_vectors_page(void)
	59	{
	60	extern char __kuser_helper_start[], __kuser_helper_end[];
a1d5ebaf ML	61	extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
a1d5ebaf ML	62
9031fefd	63	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
a1d5ebaf	64	int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
9031fefd WD	65	unsigned long vpage;
	66
	67	vpage = get_zeroed_page(GFP_ATOMIC);
	68
	69	if (!vpage)
	70	return -ENOMEM;
	71
	72	/* kuser helpers */
	73	memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
	74	kuser_sz);
	75
	76	/* sigreturn code */
	77	memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
a1d5ebaf	78	__aarch32_sigret_code_start, sigret_sz);
9031fefd WD	79
	80	flush_icache_range(vpage, vpage + PAGE_SIZE);
	81	vectors_page[0] = virt_to_page(vpage);
	82
	83	return 0;
	84	}
	85	arch_initcall(alloc_vectors_page);
	86
	87	int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
	88	{
	89	struct mm_struct *mm = current->mm;
	90	unsigned long addr = AARCH32_VECTORS_BASE;
	91	int ret;
	92
	93	down_write(&mm->mmap_sem);
	94	current->mm->context.vdso = (void *)addr;
	95
	96	/* Map vectors page at the high address. */
	97	ret = install_special_mapping(mm, addr, PAGE_SIZE,
	98	VM_READ\|VM_EXEC\|VM_MAYREAD\|VM_MAYEXEC,
	99	vectors_page);
	100
	101	up_write(&mm->mmap_sem);
	102
	103	return ret;
	104	}
	105	#endif /* CONFIG_COMPAT */
	106
	107	static int __init vdso_init(void)
	108	{
	109	struct page *pg;
	110	char *vbase;
	111	int i, ret = 0;
	112
	113	vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
	114	pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n",
	115	vdso_pages + 1, vdso_pages, 1L, &vdso_start);
	116
	117	/* Allocate the vDSO pagelist, plus a page for the data. */
	118	vdso_pagelist = kzalloc(sizeof(struct page ) (vdso_pages + 1),
	119	GFP_KERNEL);
	120	if (vdso_pagelist == NULL) {
	121	pr_err("Failed to allocate vDSO pagelist!\n");
	122	return -ENOMEM;
	123	}
	124
	125	/* Grab the vDSO code pages. */
	126	for (i = 0; i < vdso_pages; i++) {
	127	pg = virt_to_page(&vdso_start + i*PAGE_SIZE);
	128	ClearPageReserved(pg);
	129	get_page(pg);
	130	vdso_pagelist[i] = pg;
	131	}
	132
	133	/* Sanity check the shared object header. */
	134	vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL);
	135	if (vbase == NULL) {
	136	pr_err("Failed to map vDSO pagelist!\n");
	137	return -ENOMEM;
	138	} else if (memcmp(vbase, "\177ELF", 4)) {
	139	pr_err("vDSO is not a valid ELF object!\n");
	140	ret = -EINVAL;
	141	goto unmap;
	142	}
143
144	/* Grab the vDSO data page. */
145	pg = virt_to_page(vdso_data);
146	get_page(pg);
147	vdso_pagelist[i] = pg;
148
149	unmap:
150	vunmap(vbase);
151	return ret;
152	}
153	arch_initcall(vdso_init);
154
155	int arch_setup_additional_pages(struct linux_binprm *bprm,
156	int uses_interp)
157	{
158	struct mm_struct *mm = current->mm;
159	unsigned long vdso_base, vdso_mapping_len;
160	int ret;
161
162	/* Be sure to map the data page */
163	vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT;
164
165	down_write(&mm->mmap_sem);
166	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
167	if (IS_ERR_VALUE(vdso_base)) {
168	ret = vdso_base;
169	goto up_fail;
170	}
171	mm->context.vdso = (void *)vdso_base;
172
173	ret = install_special_mapping(mm, vdso_base, vdso_mapping_len,
174	VM_READ\|VM_EXEC\|
175	VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC,
176	vdso_pagelist);
177	if (ret) {
178	mm->context.vdso = NULL;
179	goto up_fail;
180	}
181
182	up_fail:
183	up_write(&mm->mmap_sem);
184
185	return ret;
186	}
187
188	const char arch_vma_name(struct vm_area_struct vma)
189	{
190	/*
191	* We can re-use the vdso pointer in mm_context_t for identifying
192	* the vectors page for compat applications. The vDSO will always
193	* sit above TASK_UNMAPPED_BASE and so we don't need to worry about
194	* it conflicting with the vectors base.
195	*/
196	if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) {
197	#ifdef CONFIG_COMPAT
198	if (vma->vm_start == AARCH32_VECTORS_BASE)
199	return "[vectors]";
200	#endif
201	return "[vdso]";
202	}
203
204	return NULL;
205	}
206
207	/*
208	* We define AT_SYSINFO_EHDR, so we need these function stubs to keep
209	* Linux happy.
210	*/
211	int in_gate_area_no_mm(unsigned long addr)
212	{
213	return 0;
214	}
215
216	int in_gate_area(struct mm_struct *mm, unsigned long addr)
217	{
218	return 0;
219	}
220
221	struct vm_area_struct get_gate_vma(struct mm_struct mm)
222	{
223	return NULL;
224	}
225
226	/*
227	* Update the vDSO data page to keep in sync with kernel timekeeping.
228	*/
c60b0c28	229	void update_vsyscall(struct timekeeper *tk)
9031fefd WD	230	{
9031fefd WD	231	struct timespec xtime_coarse;
c60b0c28	232	u32 use_syscall = strcmp(tk->clock->name, "arch_sys_counter");
9031fefd WD	233
	234	++vdso_data->tb_seq_count;
	235	smp_wmb();
	236
	237	xtime_coarse = __current_kernel_time();
	238	vdso_data->use_syscall = use_syscall;
	239	vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec;
	240	vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec;
d4022a33 NL	241	vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
d4022a33 NL	242	vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
9031fefd WD	243
9031fefd WD	244	if (!use_syscall) {
c60b0c28 CM	245	vdso_data->cs_cycle_last = tk->clock->cycle_last;
c60b0c28 CM	246	vdso_data->xtime_clock_sec = tk->xtime_sec;
45a7905f	247	vdso_data->xtime_clock_nsec = tk->xtime_nsec;
c60b0c28 CM	248	vdso_data->cs_mult = tk->mult;
c60b0c28 CM	249	vdso_data->cs_shift = tk->shift;
9031fefd WD	250	}
	251
	252	smp_wmb();
	253	++vdso_data->tb_seq_count;
	254	}
	255
	256	void update_vsyscall_tz(void)
	257	{
9031fefd WD	258	vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
9031fefd WD	259	vdso_data->tz_dsttime = sys_tz.tz_dsttime;
9031fefd	260	}