C++ pgd_alloc函数代码示例

static int __init init_static_idmap(void)
{
	idmap_pgd = pgd_alloc(&init_mm);
	if (!idmap_pgd)
		return -ENOMEM;

	identity_mapping_add(idmap_pgd, __idmap_text_start,
			     __idmap_text_end, 0);

	/* Flush L1 for the hardware to see this page table content */
	flush_cache_louis();

	return 0;
}

static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
			   unsigned long nr)
{
	/* Reuse the original kernel mapping */
	tboot_pg_dir = pgd_alloc(&tboot_mm);
	if (!tboot_pg_dir)
		return -1;

	for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
		if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
			return -1;
	}

	return 0;
}

int new_page_tables(struct task_struct * tsk)
{
	pgd_t * page_dir, * new_pg;

	if (!(new_pg = pgd_alloc()))
		return -ENOMEM;
	page_dir = pgd_offset(&init_mm, 0);
	flush_cache_mm(tsk->mm);
	memcpy(new_pg + USER_PTRS_PER_PGD, page_dir + USER_PTRS_PER_PGD,
	       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof (pgd_t));
	flush_tlb_mm(tsk->mm);
	SET_PAGE_DIR(tsk, new_pg);
	tsk->mm->pgd = new_pg;
	return 0;
}

static bool __init efi_virtmap_init(void)
{
	efi_memory_desc_t *md;
	bool systab_found;

	efi_mm.pgd = pgd_alloc(&efi_mm);
	init_new_context(NULL, &efi_mm);

	systab_found = false;
	for_each_efi_memory_desc(md) {
		phys_addr_t phys = md->phys_addr;
		int ret;

		if (!(md->attribute & EFI_MEMORY_RUNTIME))
			continue;
		if (md->virt_addr == 0)
			return false;

		ret = efi_create_mapping(&efi_mm, md);
		if  (!ret) {
			pr_info("  EFI remap %pa => %p\n",
				&phys, (void *)(unsigned long)md->virt_addr);
		} else {
			pr_warn("  EFI remap %pa: failed to create mapping (%d)\n",
				&phys, ret);
			return false;
		}
		/*
		 * If this entry covers the address of the UEFI system table,
		 * calculate and record its virtual address.
		 */
		if (efi_system_table >= phys &&
		    efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
			efi.systab = (void *)(unsigned long)(efi_system_table -
							     phys + md->virt_addr);
			systab_found = true;
		}
	}
	if (!systab_found) {
		pr_err("No virtual mapping found for the UEFI System Table\n");
		return false;
	}

	if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
		return false;

	return true;
}

static int __init init_static_idmap(void)
{
	phys_addr_t idmap_start, idmap_end;

	idmap_pgd = pgd_alloc(&init_mm);
	if (!idmap_pgd)
		return -ENOMEM;

	/* Add an identity mapping for the physical address of the section. */
	idmap_start = virt_to_phys((void *)__idmap_text_start);
	idmap_end = virt_to_phys((void *)__idmap_text_end);

	pr_info("Setting up static identity map for 0x%llx - 0x%llx\n",
		(long long)idmap_start, (long long)idmap_end);
	identity_mapping_add(idmap_pgd, idmap_start, idmap_end);

	return 0;
}

static int __init init_static_idmap(void)
{
	int ret;

	idmap_pgd = pgd_alloc(&init_mm);
	if (!idmap_pgd)
		return -ENOMEM;

	pr_info("Setting up static identity map for 0x%p - 0x%p\n",
		__idmap_text_start, __idmap_text_end);
	identity_mapping_add(idmap_pgd, __idmap_text_start,
			     __idmap_text_end, 0);

	ret = init_static_idmap_hyp();

	/* Flush L1 for the hardware to see this page table content */
	flush_cache_louis();

	return ret;
}

static int __init init_static_idmap(void)
{
	phys_addr_t idmap_start, idmap_end;

	idmap_pgd = pgd_alloc(&init_mm);
	if (!idmap_pgd)
		return -ENOMEM;

	/* Add an identity mapping for the physical address of the section. */
	idmap_start = virt_to_phys((void *)__idmap_text_start);
	idmap_end = virt_to_phys((void *)__idmap_text_end);

	pr_info("Setting up static identity map for 0x%llx - 0x%llx\n",
		(long long)idmap_start, (long long)idmap_end);
	identity_mapping_add(idmap_pgd, idmap_start, idmap_end);

	/* Flush L1 for the hardware to see this page table content */
	flush_cache_louis();

	return 0;
}

/*
 * Initialize the power management subsystem.
 *
 * Return value:
 *      -ENODEV: initialization failed
 *      0: success
 */
static int __init msm_pm_init(void)
{
	int ret;
	int val;
	enum msm_pm_time_stats_id enable_stats[] = {
		MSM_PM_STAT_REQUESTED_IDLE,
		MSM_PM_STAT_IDLE_SPIN,
		MSM_PM_STAT_IDLE_WFI,
		MSM_PM_STAT_IDLE_STANDALONE_POWER_COLLAPSE,
		MSM_PM_STAT_IDLE_FAILED_STANDALONE_POWER_COLLAPSE,
		MSM_PM_STAT_IDLE_POWER_COLLAPSE,
		MSM_PM_STAT_IDLE_FAILED_POWER_COLLAPSE,
		MSM_PM_STAT_SUSPEND,
		MSM_PM_STAT_FAILED_SUSPEND,
		MSM_PM_STAT_NOT_IDLE,
	};

#ifdef CONFIG_CPU_V7
	pgd_t *pc_pgd;
	pmd_t *pmd;
	unsigned long pmdval;
	unsigned long exit_phys;

	exit_phys = virt_to_phys(msm_pm_collapse_exit);

	/* Page table for cores to come back up safely. */
	pc_pgd = pgd_alloc(&init_mm);
	if (!pc_pgd)
		return -ENOMEM;
	pmd = pmd_offset(pud_offset(pc_pgd + pgd_index(exit_phys), exit_phys),
			 exit_phys);
	pmdval = (exit_phys & PGDIR_MASK) |
		     PMD_TYPE_SECT | PMD_SECT_AP_WRITE;
	pmd[0] = __pmd(pmdval);
	pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1)));

	msm_saved_state_phys =
		allocate_contiguous_ebi_nomap(CPU_SAVED_STATE_SIZE *
					      num_possible_cpus(), 4);
	if (!msm_saved_state_phys)
		return -ENOMEM;
	msm_saved_state = ioremap_nocache(msm_saved_state_phys,
					  CPU_SAVED_STATE_SIZE *
					  num_possible_cpus());
	if (!msm_saved_state)
		return -ENOMEM;

	/* It is remotely possible that the code in msm_pm_collapse_exit()
	 * which turns on the MMU with this mapping is in the
	 * next even-numbered megabyte beyond the
	 * start of msm_pm_collapse_exit().
	 * Map this megabyte in as well.
	 */
	pmd[2] = __pmd(pmdval + (2 << (PGDIR_SHIFT - 1)));
	flush_pmd_entry(pmd);
	msm_pm_pc_pgd = virt_to_phys(pc_pgd);
	clean_caches((unsigned long)&msm_pm_pc_pgd, sizeof(msm_pm_pc_pgd),
		     virt_to_phys(&msm_pm_pc_pgd));
#endif

	msm_pm_smem_data = smem_alloc(SMEM_APPS_DEM_SLAVE_DATA,
		sizeof(*msm_pm_smem_data));
	if (msm_pm_smem_data == NULL) {
		printk(KERN_ERR "%s: failed to get smsm_data\n", __func__);
		return -ENODEV;
	}

	ret = msm_timer_init_time_sync(msm_pm_timeout);
	if (ret)
		return ret;

	ret = smsm_change_intr_mask(SMSM_POWER_MASTER_DEM, 0xFFFFFFFF, 0);
	if (ret) {
		printk(KERN_ERR "%s: failed to clear interrupt mask, %d\n",
			__func__, ret);
		return ret;
	}

	if (cpu_is_msm8625()) {
		target_type = TARGET_IS_8625;
		clean_caches((unsigned long)&target_type, sizeof(target_type),
				virt_to_phys(&target_type));

		/*
		 * Configure the MPA5_GDFS_CNT_VAL register for
		 * DBGPWRUPEREQ_OVERRIDE[17:16] = Override the
		 * DBGNOPOWERDN for each cpu.
		 * MPA5_GDFS_CNT_VAL[9:0] = Delay counter for
		 * GDFS control.
		 */
		val = 0x00030002;
		__raw_writel(val, (MSM_CFG_CTL_BASE + 0x38));

//.........这里部分代码省略.........