Commit 775d37d8 authored by Kiryl Shutsemau's avatar Kiryl Shutsemau Committed by Ingo Molnar
Browse files

x86/acpi: Replace manual page table initialization with kernel_ident_mapping_init() 



The init_transition_pgtable() functions maps the page with
asm_acpi_mp_play_dead() into an identity mapping.

Replace open-coded manual page table initialization with
kernel_ident_mapping_init() to avoid code duplication.

Use x86_mapping_info::offset to get the page mapped at the
correct location.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarKai Huang <kai.huang@intel.com>
Reviewed-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20241016111458.846228-3-kirill.shutemov@linux.intel.com
parent 634ab761

arch/x86/kernel/acpi/madt_wakeup.c

+15 −58
Original line number Diff line number Diff line
@@ -70,58 +70,6 @@ static void __init free_pgt_page(void *pgt, void *dummy) 
	return memblock_free(pgt, PAGE_SIZE);

}



/*

 * Make sure asm_acpi_mp_play_dead() is present in the identity mapping at

 * the same place as in the kernel page tables. asm_acpi_mp_play_dead() switches

 * to the identity mapping and the function has be present at the same spot in

 * the virtual address space before and after switching page tables.

 */

static int __init init_transition_pgtable(pgd_t *pgd)

{

	pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;

	unsigned long vaddr, paddr;

	p4d_t *p4d;

	pud_t *pud;

	pmd_t *pmd;

	pte_t *pte;



	vaddr = (unsigned long)asm_acpi_mp_play_dead;

	pgd += pgd_index(vaddr);

	if (!pgd_present(*pgd)) {

		p4d = (p4d_t *)alloc_pgt_page(NULL);

		if (!p4d)

			return -ENOMEM;

		set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE));

	}

	p4d = p4d_offset(pgd, vaddr);

	if (!p4d_present(*p4d)) {

		pud = (pud_t *)alloc_pgt_page(NULL);

		if (!pud)

			return -ENOMEM;

		set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));

	}

	pud = pud_offset(p4d, vaddr);

	if (!pud_present(*pud)) {

		pmd = (pmd_t *)alloc_pgt_page(NULL);

		if (!pmd)

			return -ENOMEM;

		set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));

	}

	pmd = pmd_offset(pud, vaddr);

	if (!pmd_present(*pmd)) {

		pte = (pte_t *)alloc_pgt_page(NULL);

		if (!pte)

			return -ENOMEM;

		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));

	}

	pte = pte_offset_kernel(pmd, vaddr);



	paddr = __pa(vaddr);

	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));



	return 0;

}



static int __init acpi_mp_setup_reset(u64 reset_vector)

{

	struct x86_mapping_info info = {
@@ -130,6 +78,7 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) 
		.page_flag      = __PAGE_KERNEL_LARGE_EXEC,

		.kernpg_flag    = _KERNPG_TABLE_NOENC,

	};

	unsigned long mstart, mend;

	pgd_t *pgd;



	pgd = alloc_pgt_page(NULL);
@@ -137,8 +86,6 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) 
		return -ENOMEM;



	for (int i = 0; i < nr_pfn_mapped; i++) {

		unsigned long mstart, mend;



		mstart = pfn_mapped[i].start << PAGE_SHIFT;

		mend   = pfn_mapped[i].end << PAGE_SHIFT;

		if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) {
@@ -147,14 +94,24 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) 
		}

	}



	if (kernel_ident_mapping_init(&info, pgd,

				      PAGE_ALIGN_DOWN(reset_vector),

				      PAGE_ALIGN(reset_vector + 1))) {

	mstart = PAGE_ALIGN_DOWN(reset_vector);

	mend = mstart + PAGE_SIZE;

	if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) {

		kernel_ident_mapping_free(&info, pgd);

		return -ENOMEM;

	}



	if (init_transition_pgtable(pgd)) {

	/*

	 * Make sure asm_acpi_mp_play_dead() is present in the identity mapping

	 * at the same place as in the kernel page tables.

	 * asm_acpi_mp_play_dead() switches to the identity mapping and the

	 * function must be present at the same spot in the virtual address space

	 * before and after switching page tables.

	 */

	info.offset = __START_KERNEL_map - phys_base;

	mstart = PAGE_ALIGN_DOWN(__pa(asm_acpi_mp_play_dead));

	mend = mstart + PAGE_SIZE;

	if (kernel_ident_mapping_init(&info, pgd, mstart, mend)) {

		kernel_ident_mapping_free(&info, pgd);

		return -ENOMEM;

	}