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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hibernate_64.c (3839B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Hibernation support for x86-64
      4 *
      5 * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
      6 * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
      7 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
      8 */
      9
     10#include <linux/gfp.h>
     11#include <linux/smp.h>
     12#include <linux/suspend.h>
     13#include <linux/scatterlist.h>
     14#include <linux/kdebug.h>
     15#include <linux/pgtable.h>
     16
     17#include <crypto/hash.h>
     18
     19#include <asm/e820/api.h>
     20#include <asm/init.h>
     21#include <asm/proto.h>
     22#include <asm/page.h>
     23#include <asm/mtrr.h>
     24#include <asm/sections.h>
     25#include <asm/suspend.h>
     26#include <asm/tlbflush.h>
     27
     28static int set_up_temporary_text_mapping(pgd_t *pgd)
     29{
     30	pmd_t *pmd;
     31	pud_t *pud;
     32	p4d_t *p4d = NULL;
     33	pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
     34	pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);
     35
     36	/* Filter out unsupported __PAGE_KERNEL* bits: */
     37	pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
     38	pgprot_val(pgtable_prot)  &= __default_kernel_pte_mask;
     39
     40	/*
     41	 * The new mapping only has to cover the page containing the image
     42	 * kernel's entry point (jump_address_phys), because the switch over to
     43	 * it is carried out by relocated code running from a page allocated
     44	 * specifically for this purpose and covered by the identity mapping, so
     45	 * the temporary kernel text mapping is only needed for the final jump.
     46	 * Moreover, in that mapping the virtual address of the image kernel's
     47	 * entry point must be the same as its virtual address in the image
     48	 * kernel (restore_jump_address), so the image kernel's
     49	 * restore_registers() code doesn't find itself in a different area of
     50	 * the virtual address space after switching over to the original page
     51	 * tables used by the image kernel.
     52	 */
     53
     54	if (pgtable_l5_enabled()) {
     55		p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
     56		if (!p4d)
     57			return -ENOMEM;
     58	}
     59
     60	pud = (pud_t *)get_safe_page(GFP_ATOMIC);
     61	if (!pud)
     62		return -ENOMEM;
     63
     64	pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
     65	if (!pmd)
     66		return -ENOMEM;
     67
     68	set_pmd(pmd + pmd_index(restore_jump_address),
     69		__pmd((jump_address_phys & PMD_MASK) | pgprot_val(pmd_text_prot)));
     70	set_pud(pud + pud_index(restore_jump_address),
     71		__pud(__pa(pmd) | pgprot_val(pgtable_prot)));
     72	if (p4d) {
     73		p4d_t new_p4d = __p4d(__pa(pud) | pgprot_val(pgtable_prot));
     74		pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
     75
     76		set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
     77		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
     78	} else {
     79		/* No p4d for 4-level paging: point the pgd to the pud page table */
     80		pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
     81		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
     82	}
     83
     84	return 0;
     85}
     86
     87static void *alloc_pgt_page(void *context)
     88{
     89	return (void *)get_safe_page(GFP_ATOMIC);
     90}
     91
     92static int set_up_temporary_mappings(void)
     93{
     94	struct x86_mapping_info info = {
     95		.alloc_pgt_page	= alloc_pgt_page,
     96		.page_flag	= __PAGE_KERNEL_LARGE_EXEC,
     97		.offset		= __PAGE_OFFSET,
     98	};
     99	unsigned long mstart, mend;
    100	pgd_t *pgd;
    101	int result;
    102	int i;
    103
    104	pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
    105	if (!pgd)
    106		return -ENOMEM;
    107
    108	/* Prepare a temporary mapping for the kernel text */
    109	result = set_up_temporary_text_mapping(pgd);
    110	if (result)
    111		return result;
    112
    113	/* Set up the direct mapping from scratch */
    114	for (i = 0; i < nr_pfn_mapped; i++) {
    115		mstart = pfn_mapped[i].start << PAGE_SHIFT;
    116		mend   = pfn_mapped[i].end << PAGE_SHIFT;
    117
    118		result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
    119		if (result)
    120			return result;
    121	}
    122
    123	temp_pgt = __pa(pgd);
    124	return 0;
    125}
    126
    127asmlinkage int swsusp_arch_resume(void)
    128{
    129	int error;
    130
    131	/* We have got enough memory and from now on we cannot recover */
    132	error = set_up_temporary_mappings();
    133	if (error)
    134		return error;
    135
    136	error = relocate_restore_code();
    137	if (error)
    138		return error;
    139
    140	restore_image();
    141	return 0;
    142}