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/*
* Copyright (C) 2015 Imagination Technologies
* Author: Alex Smith <alex.smith@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/timekeeper_internal.h>
#include <asm/abi.h>
#include <asm/mips-cps.h>
#include <asm/page.h>
#include <asm/vdso.h>
/* Kernel-provided data used by the VDSO. */
static union mips_vdso_data vdso_data __page_aligned_data;
/*
* Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as
* what we map and where within the area they are mapped is determined at
* runtime.
*/
static struct page *no_pages[] = { NULL };
static struct vm_special_mapping vdso_vvar_mapping = {
.name = "[vvar]",
.pages = no_pages,
};
static void __init init_vdso_image(struct mips_vdso_image *image)
{
unsigned long num_pages, i;
unsigned long data_pfn;
BUG_ON(!PAGE_ALIGNED(image->data));
BUG_ON(!PAGE_ALIGNED(image->size));
num_pages = image->size / PAGE_SIZE;
data_pfn = __phys_to_pfn(__pa_symbol(image->data));
for (i = 0; i < num_pages; i++)
image->mapping.pages[i] = pfn_to_page(data_pfn + i);
}
static int __init init_vdso(void)
{
init_vdso_image(&vdso_image);
#ifdef CONFIG_MIPS32_O32
init_vdso_image(&vdso_image_o32);
#endif
#ifdef CONFIG_MIPS32_N32
init_vdso_image(&vdso_image_n32);
#endif
return 0;
}
subsys_initcall(init_vdso);
void update_vsyscall(struct timekeeper *tk)
{
vdso_data_write_begin(&vdso_data);
vdso_data.xtime_sec = tk->xtime_sec;
vdso_data.xtime_nsec = tk->tkr_mono.xtime_nsec;
vdso_data.wall_to_mono_sec = tk->wall_to_monotonic.tv_sec;
vdso_data.wall_to_mono_nsec = tk->wall_to_monotonic.tv_nsec;
vdso_data.cs_shift = tk->tkr_mono.shift;
vdso_data.clock_mode = tk->tkr_mono.clock->archdata.vdso_clock_mode;
if (vdso_data.clock_mode != VDSO_CLOCK_NONE) {
vdso_data.cs_mult = tk->tkr_mono.mult;
vdso_data.cs_cycle_last = tk->tkr_mono.cycle_last;
vdso_data.cs_mask = tk->tkr_mono.mask;
}
vdso_data_write_end(&vdso_data);
}
void update_vsyscall_tz(void)
{
if (vdso_data.clock_mode != VDSO_CLOCK_NONE) {
vdso_data.tz_minuteswest = sys_tz.tz_minuteswest;
vdso_data.tz_dsttime = sys_tz.tz_dsttime;
}
}
static unsigned long vdso_base(void)
{
unsigned long base;
/* Skip the delay slot emulation page */
base = STACK_TOP + PAGE_SIZE;
if (current->flags & PF_RANDOMIZE) {
base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
base = PAGE_ALIGN(base);
}
return base;
}
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mips_vdso_image *image = current->thread.abi->vdso;
struct mm_struct *mm = current->mm;
unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn;
struct vm_area_struct *vma;
int ret;
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
/* Map delay slot emulation page */
base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
VM_READ | VM_EXEC |
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
0, NULL);
if (IS_ERR_VALUE(base)) {
ret = base;
goto out;
}
/*
* Determine total area size. This includes the VDSO data itself, the
* data page, and the GIC user page if present. Always create a mapping
* for the GIC user area if the GIC is present regardless of whether it
* is the current clocksource, in case it comes into use later on. We
* only map a page even though the total area is 64K, as we only need
* the counter registers at the start.
*/
gic_size = mips_gic_present() ? PAGE_SIZE : 0;
vvar_size = gic_size + PAGE_SIZE;
size = vvar_size + image->size;
/*
* Find a region that's large enough for us to perform the
* colour-matching alignment below.
*/
if (cpu_has_dc_aliases)
size += shm_align_mask + 1;
base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
if (IS_ERR_VALUE(base)) {
ret = base;
goto out;
}
/*
* If we suffer from dcache aliasing, ensure that the VDSO data page
* mapping is coloured the same as the kernel's mapping of that memory.
* This ensures that when the kernel updates the VDSO data userland
* will observe it without requiring cache invalidations.
*/
if (cpu_has_dc_aliases) {
base = __ALIGN_MASK(base, shm_align_mask);
base += ((unsigned long)&vdso_data - gic_size) & shm_align_mask;
}
data_addr = base + gic_size;
vdso_addr = data_addr + PAGE_SIZE;
vma = _install_special_mapping(mm, base, vvar_size,
VM_READ | VM_MAYREAD,
&vdso_vvar_mapping);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto out;
}
/* Map GIC user page. */
if (gic_size) {
gic_pfn = virt_to_phys(mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT;
ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
pgprot_noncached(PAGE_READONLY));
if (ret)
goto out;
}
/* Map data page. */
ret = remap_pfn_range(vma, data_addr,
virt_to_phys(&vdso_data) >> PAGE_SHIFT,
PAGE_SIZE, PAGE_READONLY);
if (ret)
goto out;
/* Map VDSO image. */
vma = _install_special_mapping(mm, vdso_addr, image->size,
VM_READ | VM_EXEC |
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
&image->mapping);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto out;
}
mm->context.vdso = (void *)vdso_addr;
ret = 0;
out:
up_write(&mm->mmap_sem);
return ret;
}
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