cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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vdso.c (3224B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Author: Huacai Chen <chenhuacai@loongson.cn>
      4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
      5 */
      6
      7#include <linux/binfmts.h>
      8#include <linux/elf.h>
      9#include <linux/err.h>
     10#include <linux/init.h>
     11#include <linux/ioport.h>
     12#include <linux/kernel.h>
     13#include <linux/mm.h>
     14#include <linux/random.h>
     15#include <linux/sched.h>
     16#include <linux/slab.h>
     17#include <linux/timekeeper_internal.h>
     18
     19#include <asm/page.h>
     20#include <asm/vdso.h>
     21#include <vdso/helpers.h>
     22#include <vdso/vsyscall.h>
     23#include <generated/vdso-offsets.h>
     24
     25extern char vdso_start[], vdso_end[];
     26
     27/* Kernel-provided data used by the VDSO. */
     28static union loongarch_vdso_data {
     29	u8 page[PAGE_SIZE];
     30	struct vdso_data data[CS_BASES];
     31} loongarch_vdso_data __page_aligned_data;
     32struct vdso_data *vdso_data = loongarch_vdso_data.data;
     33static struct page *vdso_pages[] = { NULL };
     34
     35static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
     36{
     37	current->mm->context.vdso = (void *)(new_vma->vm_start);
     38
     39	return 0;
     40}
     41
     42struct loongarch_vdso_info vdso_info = {
     43	.vdso = vdso_start,
     44	.size = PAGE_SIZE,
     45	.code_mapping = {
     46		.name = "[vdso]",
     47		.pages = vdso_pages,
     48		.mremap = vdso_mremap,
     49	},
     50	.data_mapping = {
     51		.name = "[vvar]",
     52	},
     53	.offset_sigreturn = vdso_offset_sigreturn,
     54};
     55
     56static int __init init_vdso(void)
     57{
     58	unsigned long i, pfn;
     59
     60	BUG_ON(!PAGE_ALIGNED(vdso_info.vdso));
     61	BUG_ON(!PAGE_ALIGNED(vdso_info.size));
     62
     63	pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso));
     64	for (i = 0; i < vdso_info.size / PAGE_SIZE; i++)
     65		vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i);
     66
     67	return 0;
     68}
     69subsys_initcall(init_vdso);
     70
     71static unsigned long vdso_base(void)
     72{
     73	unsigned long base = STACK_TOP;
     74
     75	if (current->flags & PF_RANDOMIZE) {
     76		base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
     77		base = PAGE_ALIGN(base);
     78	}
     79
     80	return base;
     81}
     82
     83int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
     84{
     85	int ret;
     86	unsigned long vvar_size, size, data_addr, vdso_addr;
     87	struct mm_struct *mm = current->mm;
     88	struct vm_area_struct *vma;
     89	struct loongarch_vdso_info *info = current->thread.vdso;
     90
     91	if (mmap_write_lock_killable(mm))
     92		return -EINTR;
     93
     94	/*
     95	 * Determine total area size. This includes the VDSO data itself
     96	 * and the data page.
     97	 */
     98	vvar_size = PAGE_SIZE;
     99	size = vvar_size + info->size;
    100
    101	data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
    102	if (IS_ERR_VALUE(data_addr)) {
    103		ret = data_addr;
    104		goto out;
    105	}
    106	vdso_addr = data_addr + PAGE_SIZE;
    107
    108	vma = _install_special_mapping(mm, data_addr, vvar_size,
    109				       VM_READ | VM_MAYREAD,
    110				       &info->data_mapping);
    111	if (IS_ERR(vma)) {
    112		ret = PTR_ERR(vma);
    113		goto out;
    114	}
    115
    116	/* Map VDSO data page. */
    117	ret = remap_pfn_range(vma, data_addr,
    118			      virt_to_phys(vdso_data) >> PAGE_SHIFT,
    119			      PAGE_SIZE, PAGE_READONLY);
    120	if (ret)
    121		goto out;
    122
    123	/* Map VDSO code page. */
    124	vma = _install_special_mapping(mm, vdso_addr, info->size,
    125				       VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
    126				       &info->code_mapping);
    127	if (IS_ERR(vma)) {
    128		ret = PTR_ERR(vma);
    129		goto out;
    130	}
    131
    132	mm->context.vdso = (void *)vdso_addr;
    133	ret = 0;
    134
    135out:
    136	mmap_write_unlock(mm);
    137	return ret;
    138}