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/*
* VDSO implementation for AArch32. Derived from arm64/kernel/vdso.c
*
* Copyright (c) 2009-2014, NVIDIA CORPORATION. All rights reserved.
* Original 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/signal.h>
#include <asm/vdso.h>
#include <asm/vdso_datapage.h>
extern char vdso32_start, vdso32_end;
static unsigned long vdso32_pages;
static struct page **vdso32_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;
static int __init vdso_init(void)
{
struct page *pg;
char *vbase32;
int i, ret = 0;
vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
pr_info("vdso32: %ld pages (%ld code, %ld data) at base %p\n",
vdso32_pages + 1, vdso32_pages, 1L, &vdso32_start);
vdso32_pagelist = kzalloc(sizeof(struct page *) * (vdso32_pages + 1),
GFP_KERNEL);
if (vdso32_pagelist == NULL) {
pr_err("Failed to allocate vDSO32 pagelist!\n");
return -ENOMEM;
}
/* Grab the vDSO code pages. */
for (i = 0; i < vdso32_pages; i++) {
pg = virt_to_page(&vdso32_start + i*PAGE_SIZE);
ClearPageReserved(pg);
get_page(pg);
vdso32_pagelist[i] = pg;
}
/* Sanity check the shared object header. */
vbase32 = vmap(vdso32_pagelist, 1, 0, PAGE_KERNEL);
if (vbase32 == NULL) {
pr_err("Failed to map vDSO pagelist!\n");
return -ENOMEM;
} else if (memcmp(vbase32, "\177ELF", 4)) {
pr_err("vDSO 32 is not a valid ELF object!\n");
ret = -EINVAL;
goto unmap32;
}
/* Grab the vDSO data page. */
pg = virt_to_page(vdso_data);
get_page(pg);
vdso32_pagelist[i] = pg;
unmap32:
vunmap(vbase32);
return ret;
}
arch_initcall(vdso_init);
int vdso_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp)
{
struct mm_struct *mm = current->mm;
unsigned long vdso_base, vdso_mapping_len;
struct page **local_vdso_pagelist;
unsigned long local_vdso_pages;
int ret;
local_vdso_pagelist = vdso32_pagelist;
local_vdso_pages = vdso32_pages;
/* Be sure to map the data page */
vdso_mapping_len = (local_vdso_pages + 1) << PAGE_SHIFT;
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,
local_vdso_pagelist);
if (ret) {
mm->context.vdso = NULL;
goto up_fail;
}
up_fail:
return 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->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;
}
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