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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2012 ARM Limited
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/cache.h>
#include <linux/clocksource.h>
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/kernel.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 <linux/random.h>
#include <asm/cacheflush.h>
#include <asm/vdso.h>
#include <asm/vdso_datapage.h>
#include <asm/vdso_timer_info.h>
#include <asm/cache_info.h>
extern struct cache_info L1_cache_info[2];
extern char vdso_start, vdso_end;
static unsigned long vdso_pages __ro_after_init;
static unsigned long timer_mapping_base;
struct timer_info_t timer_info = {
.cycle_count_down = true,
.mapping_base = EMPTY_TIMER_MAPPING,
.cycle_count_reg_offset = EMPTY_REG_OFFSET
};
/*
* The vDSO data page.
*/
static struct page *no_pages[] = { NULL };
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 struct vm_special_mapping vdso_spec[2] __ro_after_init = {
{
.name = "[vvar]",
.pages = no_pages,
},
{
.name = "[vdso]",
},
};
static void get_timer_node_info(void)
{
timer_mapping_base = timer_info.mapping_base;
vdso_data->cycle_count_offset =
timer_info.cycle_count_reg_offset;
vdso_data->cycle_count_down =
timer_info.cycle_count_down;
}
static int __init vdso_init(void)
{
int i;
struct page **vdso_pagelist;
if (memcmp(&vdso_start, "\177ELF", 4)) {
pr_err("vDSO is not a valid ELF object!\n");
return -EINVAL;
}
/* Creat a timer io mapping to get clock cycles counter */
get_timer_node_info();
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 */
vdso_pagelist = kcalloc(vdso_pages, sizeof(struct page *), GFP_KERNEL);
if (vdso_pagelist == NULL)
return -ENOMEM;
for (i = 0; i < vdso_pages; i++)
vdso_pagelist[i] = virt_to_page(&vdso_start + i * PAGE_SIZE);
vdso_spec[1].pages = &vdso_pagelist[0];
return 0;
}
arch_initcall(vdso_init);
unsigned long inline vdso_random_addr(unsigned long vdso_mapping_len)
{
unsigned long start = current->mm->mmap_base, end, offset, addr;
start = PAGE_ALIGN(start);
/* Round the lowest possible end address up to a PMD boundary. */
end = (start + vdso_mapping_len + PMD_SIZE - 1) & PMD_MASK;
if (end >= TASK_SIZE)
end = TASK_SIZE;
end -= vdso_mapping_len;
if (end > start) {
offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
addr = start + (offset << PAGE_SHIFT);
} else {
addr = start;
}
return addr;
}
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;
struct vm_area_struct *vma;
unsigned long addr = 0;
pgprot_t prot;
int ret, vvar_page_num = 2;
vdso_text_len = vdso_pages << PAGE_SHIFT;
if(timer_mapping_base == EMPTY_VALUE)
vvar_page_num = 1;
/* Be sure to map the data page */
vdso_mapping_len = vdso_text_len + vvar_page_num * PAGE_SIZE;
#ifdef CONFIG_CPU_CACHE_ALIASING
vdso_mapping_len += L1_cache_info[DCACHE].aliasing_num - 1;
#endif
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
addr = vdso_random_addr(vdso_mapping_len);
vdso_base = get_unmapped_area(NULL, addr, vdso_mapping_len, 0, 0);
if (IS_ERR_VALUE(vdso_base)) {
ret = vdso_base;
goto up_fail;
}
#ifdef CONFIG_CPU_CACHE_ALIASING
{
unsigned int aliasing_mask =
L1_cache_info[DCACHE].aliasing_mask;
unsigned int page_colour_ofs;
page_colour_ofs = ((unsigned int)vdso_data & aliasing_mask) -
(vdso_base & aliasing_mask);
vdso_base += page_colour_ofs & aliasing_mask;
}
#endif
vma = _install_special_mapping(mm, vdso_base, vvar_page_num * PAGE_SIZE,
VM_READ | VM_MAYREAD, &vdso_spec[0]);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto up_fail;
}
/*Map vdata to user space */
ret = io_remap_pfn_range(vma, vdso_base,
virt_to_phys(vdso_data) >> PAGE_SHIFT,
PAGE_SIZE, vma->vm_page_prot);
if (ret)
goto up_fail;
/*Map timer to user space */
vdso_base += PAGE_SIZE;
prot = __pgprot(_PAGE_V | _PAGE_M_UR_KR | _PAGE_D | _PAGE_C_DEV);
ret = io_remap_pfn_range(vma, vdso_base, timer_mapping_base >> PAGE_SHIFT,
PAGE_SIZE, prot);
if (ret)
goto up_fail;
/*Map vdso to user space */
vdso_base += PAGE_SIZE;
mm->context.vdso = (void *)vdso_base;
vma = _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(vma)) {
ret = PTR_ERR(vma);
goto up_fail;
}
up_write(&mm->mmap_sem);
return 0;
up_fail:
mm->context.vdso = NULL;
up_write(&mm->mmap_sem);
return ret;
}
static void vdso_write_begin(struct vdso_data *vdata)
{
++vdso_data->seq_count;
smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */
}
static void vdso_write_end(struct vdso_data *vdata)
{
smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */
++vdso_data->seq_count;
}
void update_vsyscall(struct timekeeper *tk)
{
vdso_write_begin(vdso_data);
vdso_data->cs_mask = tk->tkr_mono.mask;
vdso_data->cs_mult = tk->tkr_mono.mult;
vdso_data->cs_shift = tk->tkr_mono.shift;
vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
vdso_data->xtime_clock_sec = tk->xtime_sec;
vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
vdso_data->xtime_coarse_sec = tk->xtime_sec;
vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >>
tk->tkr_mono.shift;
vdso_write_end(vdso_data);
}
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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