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Commit 6f9dd329 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ingo Molnar
Browse files

x86/mm: Support boot-time switching of paging modes in the early boot code 



Early boot code should be able to initialize page tables for both 4- and
5-level paging modes.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214182542.69302-7-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9b46a051

arch/x86/kernel/head64.c

+22 −11
Original line number Diff line number Diff line
@@ -75,13 +75,13 @@ static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr) 
	return fixup_pointer(ptr, physaddr);

}



static void __head check_la57_support(unsigned long physaddr)

static bool __head check_la57_support(unsigned long physaddr)

{

	if (native_cpuid_eax(0) < 7)

		return;

		return false;



	if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31))))

		return;

		return false;



	*fixup_int(&pgtable_l5_enabled, physaddr) = 1;

	*fixup_int(&pgdir_shift, physaddr) = 48;
@@ -89,24 +89,30 @@ static void __head check_la57_support(unsigned long physaddr) 
	*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 void __head check_la57_support(unsigned long physaddr) {}

static bool __head check_la57_support(unsigned long physaddr)

{

	return false;

}

#endif



unsigned long __head __startup_64(unsigned long physaddr,

				  struct boot_params *bp)

{

	unsigned long load_delta;

	unsigned long load_delta, *p;

	unsigned long pgtable_flags;

	pgdval_t *pgd;

	p4dval_t *p4d;

	pudval_t *pud;

	pmdval_t *pmd, pmd_entry;

	bool la57;

	int i;

	unsigned int *next_pgt_ptr;



	check_la57_support(physaddr);

	la57 = check_la57_support(physaddr);



	/* Is the address too large? */

	if (physaddr >> MAX_PHYSMEM_BITS)
@@ -131,9 +137,14 @@ unsigned long __head __startup_64(unsigned long physaddr, 
	/* Fixup the physical addresses in the page table */



	pgd = fixup_pointer(&early_top_pgt, physaddr);

	pgd[pgd_index(__START_KERNEL_map)] += load_delta;



	if (IS_ENABLED(CONFIG_X86_5LEVEL)) {

	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;

	}
@@ -158,7 +169,7 @@ unsigned long __head __startup_64(unsigned long physaddr, 


	pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();



	if (IS_ENABLED(CONFIG_X86_5LEVEL)) {

	if (la57) {

		p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);



		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
@@ -255,7 +266,7 @@ int __init __early_make_pgtable(unsigned long address, pmdval_t pmd) 
	 * critical -- __PAGE_OFFSET would point us back into the dynamic

	 * range and we might end up looping forever...

	 */

	if (!IS_ENABLED(CONFIG_X86_5LEVEL))

	if (!pgtable_l5_enabled)

		p4d_p = pgd_p;

	else if (pgd)

		p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);

arch/x86/kernel/head_64.S

+4 −6
Original line number Diff line number Diff line
@@ -124,7 +124,10 @@ ENTRY(secondary_startup_64) 
	/* Enable PAE mode, PGE and LA57 */

	movl	$(X86_CR4_PAE | X86_CR4_PGE), %ecx

#ifdef CONFIG_X86_5LEVEL

	testl	$1, pgtable_l5_enabled(%rip)

	jz	1f

	orl	$X86_CR4_LA57, %ecx

1:

#endif

	movq	%rcx, %cr4
@@ -372,12 +375,7 @@ GLOBAL(name) 


	__INITDATA

NEXT_PGD_PAGE(early_top_pgt)

	.fill	511,8,0

#ifdef CONFIG_X86_5LEVEL

	.quad	level4_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC

#else

	.quad	level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC

#endif

	.fill	512,8,0

	.fill	PTI_USER_PGD_FILL,8,0



NEXT_PAGE(early_dynamic_pgts)