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/*
* 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;
}
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