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// SPDX-License-Identifier: GPL-2.0
/*
* prepare to run common code
*
* Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
*/
#define DISABLE_BRANCH_PROFILING
/* cpu_feature_enabled() cannot be used this early */
#define USE_EARLY_PGTABLE_L5
#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/percpu.h>
#include <linux/start_kernel.h>
#include <linux/io.h>
#include <linux/memblock.h>
#include <linux/mem_encrypt.h>
#include <asm/processor.h>
#include <asm/proto.h>
#include <asm/smp.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/kdebug.h>
#include <asm/e820/api.h>
#include <asm/bios_ebda.h>
#include <asm/bootparam_utils.h>
#include <asm/microcode.h>
#include <asm/kasan.h>
#include <asm/fixmap.h>
/*
* Manage page tables very early on.
*/
extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
static unsigned int __initdata next_early_pgt;
pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
#ifdef CONFIG_X86_5LEVEL
unsigned int __pgtable_l5_enabled __ro_after_init;
unsigned int pgdir_shift __ro_after_init = 39;
EXPORT_SYMBOL(pgdir_shift);
unsigned int ptrs_per_p4d __ro_after_init = 1;
EXPORT_SYMBOL(ptrs_per_p4d);
#endif
#ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
EXPORT_SYMBOL(page_offset_base);
unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4;
EXPORT_SYMBOL(vmalloc_base);
unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4;
EXPORT_SYMBOL(vmemmap_base);
#endif
#define __head __section(.head.text)
static void __head *fixup_pointer(void *ptr, unsigned long physaddr)
{
return ptr - (void *)_text + (void *)physaddr;
}
static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr)
{
return fixup_pointer(ptr, physaddr);
}
#ifdef CONFIG_X86_5LEVEL
static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr)
{
return fixup_pointer(ptr, physaddr);
}
static bool __head check_la57_support(unsigned long physaddr)
{
/*
* 5-level paging is detected and enabled at kernel decomression
* stage. Only check if it has been enabled there.
*/
if (!(native_read_cr4() & X86_CR4_LA57))
return false;
*fixup_int(&__pgtable_l5_enabled, physaddr) = 1;
*fixup_int(&pgdir_shift, physaddr) = 48;
*fixup_int(&ptrs_per_p4d, physaddr) = 512;
*fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5;
*fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5;
*fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5;
return true;
}
#else
static bool __head check_la57_support(unsigned long physaddr)
{
return false;
}
#endif
/* Code in __startup_64() can be relocated during execution, but the compiler
* doesn't have to generate PC-relative relocations when accessing globals from
* that function. Clang actually does not generate them, which leads to
* boot-time crashes. To work around this problem, every global pointer must
* be adjusted using fixup_pointer().
*/
unsigned long __head __startup_64(unsigned long physaddr,
struct boot_params *bp)
{
unsigned long vaddr, vaddr_end;
unsigned long load_delta, *p;
unsigned long pgtable_flags;
pgdval_t *pgd;
p4dval_t *p4d;
pudval_t *pud;
pmdval_t *pmd, pmd_entry;
pteval_t *mask_ptr;
bool la57;
int i;
unsigned int *next_pgt_ptr;
la57 = check_la57_support(physaddr);
/* Is the address too large? */
if (physaddr >> MAX_PHYSMEM_BITS)
for (;;);
/*
* Compute the delta between the address I am compiled to run at
* and the address I am actually running at.
*/
load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);
/* Is the address not 2M aligned? */
if (load_delta & ~PMD_PAGE_MASK)
for (;;);
/* Activate Secure Memory Encryption (SME) if supported and enabled */
sme_enable(bp);
/* Include the SME encryption mask in the fixup value */
load_delta += sme_get_me_mask();
/* Fixup the physical addresses in the page table */
pgd = fixup_pointer(&early_top_pgt, physaddr);
p = pgd + pgd_index(__START_KERNEL_map);
if (la57)
*p = (unsigned long)level4_kernel_pgt;
else
*p = (unsigned long)level3_kernel_pgt;
*p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;
if (la57) {
p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
p4d[511] += load_delta;
}
pud = fixup_pointer(&level3_kernel_pgt, physaddr);
pud[510] += load_delta;
pud[511] += load_delta;
pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
pmd[i] += load_delta;
/*
* Set up the identity mapping for the switchover. These
* entries should *NOT* have the global bit set! This also
* creates a bunch of nonsense entries but that is fine --
* it avoids problems around wraparound.
*/
next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr);
pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
if (la57) {
p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
physaddr);
i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
i = physaddr >> P4D_SHIFT;
p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
} else {
i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
}
i = physaddr >> PUD_SHIFT;
pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
/* Filter out unsupported __PAGE_KERNEL_* bits: */
mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr);
pmd_entry &= *mask_ptr;
pmd_entry += sme_get_me_mask();
pmd_entry += physaddr;
for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
int idx = i + (physaddr >> PMD_SHIFT);
pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
}
/*
* Fixup the kernel text+data virtual addresses. Note that
* we might write invalid pmds, when the kernel is relocated
* cleanup_highmap() fixes this up along with the mappings
* beyond _end.
*
* Only the region occupied by the kernel image has so far
* been checked against the table of usable memory regions
* provided by the firmware, so invalidate pages outside that
* region. A page table entry that maps to a reserved area of
* memory would allow processor speculation into that area,
* and on some hardware (particularly the UV platform) even
* speculative access to some reserved areas is caught as an
* error, causing the BIOS to halt the system.
*/
pmd = fixup_pointer(level2_kernel_pgt, physaddr);
/* invalidate pages before the kernel image */
for (i = 0; i < pmd_index((unsigned long)_text); i++)
pmd[i] &= ~_PAGE_PRESENT;
/* fixup pages that are part of the kernel image */
for (; <
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