[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;
	static struct vm_special_mapping spec = {
		.name	= "[vectors]",
		.pages	= vectors_page,

	};
	void *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,
				       &spec);

	up_write(&mm->mmap_sem);

	return PTR_ERR_OR_ZERO(ret);
}
#endif /* CONFIG_COMPAT */

static struct vm_special_mapping vdso_spec[2];

static int __init vdso_init(void)
{
	int i;

	if (memcmp(&vdso_start, "\177ELF", 4)) {
		pr_err("vDSO is not a valid ELF object!\n");
		return -EINVAL;
	}

	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, plus a page for the data. */
	vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
				GFP_KERNEL);
	if (vdso_pagelist == NULL)
		return -ENOMEM;

	/* Grab the vDSO data page. */
	vdso_pagelist[0] = virt_to_page(vdso_data);

	/* Grab the vDSO code pages. */
	for (i = 0; i < vdso_pages; i++)
		vdso_pagelist[i + 1] = virt_to_page(&vdso_start + i * PAGE_SIZE);

	/* Populate the special mapping structures */
	vdso_spec[0] = (struct vm_special_mapping) {
		.name	= "[vvar]",
		.pages	= vdso_pagelist,
	};

	vdso_spec[1] = (struct vm_special_mapping) {
		.name	= "[vdso]",
		.pages	= &vdso_pagelist[1],
	};

	return 0;
}
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_text_len, vdso_mapping_len;
	void *ret;

	vdso_text_len = vdso_pages << PAGE_SHIFT;
	/* Be sure to map the data page */
	vdso_mapping_len = vdso_text_len + PAGE_SIZE;

	down_write(&mm->mmap_sem);
	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
	if (IS_ERR_VALUE(vdso_base)) {
		ret = ERR_PTR(vdso_base);
		goto up_fail;
	}
	ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
				       VM_READ|VM_MAYREAD,
				       &vdso_spec[0]);
	if (IS_ERR(ret))
		goto up_fail;

	vdso_base += PAGE_SIZE;
	mm->context.vdso = (void *)vdso_base;
	ret = _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(ret))
		goto up_fail;


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

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

/*
 * 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->tkr.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->tkr.cycle_last;
		vdso_data->xtime_clock_sec	= tk->xtime_sec;
		vdso_data->xtime_clock_nsec	= tk->tkr.xtime_nsec;
		vdso_data->cs_mult		= tk->tkr.mult;
		vdso_data->cs_shift		= tk->tkr.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;
2fea7f6c WD	91	static struct vm_special_mapping spec = {
	92	.name = "[vectors]",
	93	.pages = vectors_page,
	94
	95	};
	96	void *ret;
9031fefd WD	97
	98	down_write(&mm->mmap_sem);
	99	current->mm->context.vdso = (void *)addr;
	100
	101	/* Map vectors page at the high address. */
2fea7f6c WD	102	ret = _install_special_mapping(mm, addr, PAGE_SIZE,
	103	VM_READ\|VM_EXEC\|VM_MAYREAD\|VM_MAYEXEC,
	104	&spec);
9031fefd WD	105
	106	up_write(&mm->mmap_sem);
	107
2fea7f6c	108	return PTR_ERR_OR_ZERO(ret);
9031fefd WD	109	}
	110	#endif /* CONFIG_COMPAT */
	111
2fea7f6c WD	112	static struct vm_special_mapping vdso_spec[2];
2fea7f6c WD	113
9031fefd WD	114	static int __init vdso_init(void)
9031fefd WD	115	{
16fb1a9b NL	116	int i;
	117
	118	if (memcmp(&vdso_start, "\177ELF", 4)) {
	119	pr_err("vDSO is not a valid ELF object!\n");
	120	return -EINVAL;
	121	}
9031fefd WD	122
9031fefd WD	123	vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
601255ae WD	124	pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
601255ae WD	125	vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data);
9031fefd WD	126
9031fefd WD	127	/* Allocate the vDSO pagelist, plus a page for the data. */
16fb1a9b	128	vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
9031fefd	129	GFP_KERNEL);
16fb1a9b	130	if (vdso_pagelist == NULL)
9031fefd	131	return -ENOMEM;
9031fefd	132
601255ae WD	133	/* Grab the vDSO data page. */
	134	vdso_pagelist[0] = virt_to_page(vdso_data);
	135
9031fefd	136	/* Grab the vDSO code pages. */
16fb1a9b	137	for (i = 0; i < vdso_pages; i++)
601255ae	138	vdso_pagelist[i + 1] = virt_to_page(&vdso_start + i * PAGE_SIZE);
9031fefd	139
2fea7f6c WD	140	/* Populate the special mapping structures */
2fea7f6c WD	141	vdso_spec[0] = (struct vm_special_mapping) {
601255ae	142	.name = "[vvar]",
2fea7f6c WD	143	.pages = vdso_pagelist,
	144	};
	145
	146	vdso_spec[1] = (struct vm_special_mapping) {
601255ae WD	147	.name = "[vdso]",
601255ae WD	148	.pages = &vdso_pagelist[1],
2fea7f6c WD	149	};
2fea7f6c WD	150
16fb1a9b	151	return 0;
9031fefd WD	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;
87154938	159	unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
2fea7f6c	160	void *ret;
9031fefd	161
87154938	162	vdso_text_len = vdso_pages << PAGE_SHIFT;
9031fefd	163	/* Be sure to map the data page */
87154938	164	vdso_mapping_len = vdso_text_len + PAGE_SIZE;
9031fefd WD	165
	166	down_write(&mm->mmap_sem);
	167	vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
	168	if (IS_ERR_VALUE(vdso_base)) {
2fea7f6c	169	ret = ERR_PTR(vdso_base);
9031fefd WD	170	goto up_fail;
9031fefd WD	171	}
601255ae WD	172	ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
601255ae WD	173	VM_READ\|VM_MAYREAD,
2fea7f6c WD	174	&vdso_spec[0]);
2fea7f6c WD	175	if (IS_ERR(ret))
87154938 WD	176	goto up_fail;
87154938 WD	177
601255ae WD	178	vdso_base += PAGE_SIZE;
	179	mm->context.vdso = (void *)vdso_base;
	180	ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
	181	VM_READ\|VM_EXEC\|
	182	VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC,
2fea7f6c WD	183	&vdso_spec[1]);
2fea7f6c WD	184	if (IS_ERR(ret))
9031fefd	185	goto up_fail;
9031fefd	186
601255ae	187
9031fefd	188	up_write(&mm->mmap_sem);
87154938	189	return 0;
9031fefd	190
87154938 WD	191	up_fail:
	192	mm->context.vdso = NULL;
	193	up_write(&mm->mmap_sem);
2fea7f6c	194	return PTR_ERR(ret);
9031fefd WD	195	}
9031fefd WD	196
9031fefd WD	197	/*
	198	* Update the vDSO data page to keep in sync with kernel timekeeping.
	199	*/
c60b0c28	200	void update_vsyscall(struct timekeeper *tk)
9031fefd WD	201	{
9031fefd WD	202	struct timespec xtime_coarse;
d28ede83	203	u32 use_syscall = strcmp(tk->tkr.clock->name, "arch_sys_counter");
9031fefd WD	204
	205	++vdso_data->tb_seq_count;
	206	smp_wmb();
	207
	208	xtime_coarse = __current_kernel_time();
	209	vdso_data->use_syscall = use_syscall;
	210	vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec;
	211	vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec;
d4022a33 NL	212	vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
d4022a33 NL	213	vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
9031fefd WD	214
9031fefd WD	215	if (!use_syscall) {
d28ede83	216	vdso_data->cs_cycle_last = tk->tkr.cycle_last;
c60b0c28	217	vdso_data->xtime_clock_sec = tk->xtime_sec;
d28ede83 TG	218	vdso_data->xtime_clock_nsec = tk->tkr.xtime_nsec;
	219	vdso_data->cs_mult = tk->tkr.mult;
	220	vdso_data->cs_shift = tk->tkr.shift;
9031fefd WD	221	}
	222
	223	smp_wmb();
	224	++vdso_data->tb_seq_count;
	225	}
	226
	227	void update_vsyscall_tz(void)
	228	{
9031fefd WD	229	vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
9031fefd WD	230	vdso_data->tz_dsttime = sys_tz.tz_dsttime;
9031fefd	231	}