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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head32.c (3219B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 *  linux/arch/i386/kernel/head32.c -- prepare to run common code
      4 *
      5 *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
      6 *  Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com>
      7 */
      8
      9#include <linux/init.h>
     10#include <linux/start_kernel.h>
     11#include <linux/mm.h>
     12#include <linux/memblock.h>
     13
     14#include <asm/desc.h>
     15#include <asm/setup.h>
     16#include <asm/sections.h>
     17#include <asm/e820/api.h>
     18#include <asm/page.h>
     19#include <asm/apic.h>
     20#include <asm/io_apic.h>
     21#include <asm/bios_ebda.h>
     22#include <asm/tlbflush.h>
     23#include <asm/bootparam_utils.h>
     24
     25static void __init i386_default_early_setup(void)
     26{
     27	/* Initialize 32bit specific setup functions */
     28	x86_init.resources.reserve_resources = i386_reserve_resources;
     29	x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
     30}
     31
     32asmlinkage __visible void __init i386_start_kernel(void)
     33{
     34	/* Make sure IDT is set up before any exception happens */
     35	idt_setup_early_handler();
     36
     37	cr4_init_shadow();
     38
     39	sanitize_boot_params(&boot_params);
     40
     41	x86_early_init_platform_quirks();
     42
     43	/* Call the subarch specific early setup function */
     44	switch (boot_params.hdr.hardware_subarch) {
     45	case X86_SUBARCH_INTEL_MID:
     46		x86_intel_mid_early_setup();
     47		break;
     48	case X86_SUBARCH_CE4100:
     49		x86_ce4100_early_setup();
     50		break;
     51	default:
     52		i386_default_early_setup();
     53		break;
     54	}
     55
     56	start_kernel();
     57}
     58
     59/*
     60 * Initialize page tables.  This creates a PDE and a set of page
     61 * tables, which are located immediately beyond __brk_base.  The variable
     62 * _brk_end is set up to point to the first "safe" location.
     63 * Mappings are created both at virtual address 0 (identity mapping)
     64 * and PAGE_OFFSET for up to _end.
     65 *
     66 * In PAE mode initial_page_table is statically defined to contain
     67 * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
     68 * entries). The identity mapping is handled by pointing two PGD entries
     69 * to the first kernel PMD. Note the upper half of each PMD or PTE are
     70 * always zero at this stage.
     71 */
     72void __init mk_early_pgtbl_32(void)
     73{
     74#ifdef __pa
     75#undef __pa
     76#endif
     77#define __pa(x)  ((unsigned long)(x) - PAGE_OFFSET)
     78	pte_t pte, *ptep;
     79	int i;
     80	unsigned long *ptr;
     81	/* Enough space to fit pagetables for the low memory linear map */
     82	const unsigned long limit = __pa(_end) +
     83		(PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
     84#ifdef CONFIG_X86_PAE
     85	pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd);
     86#define SET_PL2(pl2, val)    { (pl2).pmd = (val); }
     87#else
     88	pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table);
     89#define SET_PL2(pl2, val)   { (pl2).pgd = (val); }
     90#endif
     91
     92	ptep = (pte_t *)__pa(__brk_base);
     93	pte.pte = PTE_IDENT_ATTR;
     94
     95	while ((pte.pte & PTE_PFN_MASK) < limit) {
     96
     97		SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR);
     98		*pl2p = pl2;
     99#ifndef CONFIG_X86_PAE
    100		/* Kernel PDE entry */
    101		*(pl2p +  ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
    102#endif
    103		for (i = 0; i < PTRS_PER_PTE; i++) {
    104			*ptep = pte;
    105			pte.pte += PAGE_SIZE;
    106			ptep++;
    107		}
    108
    109		pl2p++;
    110	}
    111
    112	ptr = (unsigned long *)__pa(&max_pfn_mapped);
    113	/* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */
    114	*ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
    115
    116	ptr = (unsigned long *)__pa(&_brk_end);
    117	*ptr = (unsigned long)ptep + PAGE_OFFSET;
    118}
    119