asmlinkage void __init setup_vm()

in mm/init.c [592:697]

• 67 lines of code
• 2 McCabe index (conditional complexity)

asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
	pmd_t __maybe_unused fix_bmap_spmd, fix_bmap_epmd;

	kernel_map.virt_addr = KERNEL_LINK_ADDR;

#ifdef CONFIG_XIP_KERNEL
	kernel_map.xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR;
	kernel_map.xiprom_sz = (uintptr_t)(&_exiprom) - (uintptr_t)(&_xiprom);

	phys_ram_base = CONFIG_PHYS_RAM_BASE;
	kernel_map.phys_addr = (uintptr_t)CONFIG_PHYS_RAM_BASE;
	kernel_map.size = (uintptr_t)(&_end) - (uintptr_t)(&_sdata);

	kernel_map.va_kernel_xip_pa_offset = kernel_map.virt_addr - kernel_map.xiprom;
#else
	kernel_map.phys_addr = (uintptr_t)(&_start);
	kernel_map.size = (uintptr_t)(&_end) - kernel_map.phys_addr;
#endif
	kernel_map.va_pa_offset = PAGE_OFFSET - kernel_map.phys_addr;
	kernel_map.va_kernel_pa_offset = kernel_map.virt_addr - kernel_map.phys_addr;

	riscv_pfn_base = PFN_DOWN(kernel_map.phys_addr);

	/* Sanity check alignment and size */
	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
	BUG_ON((kernel_map.phys_addr % PMD_SIZE) != 0);

#ifdef CONFIG_64BIT
	/*
	 * The last 4K bytes of the addressable memory can not be mapped because
	 * of IS_ERR_VALUE macro.
	 */
	BUG_ON((kernel_map.virt_addr + kernel_map.size) > ADDRESS_SPACE_END - SZ_4K);
#endif

	pt_ops.alloc_pte = alloc_pte_early;
	pt_ops.get_pte_virt = get_pte_virt_early;
#ifndef __PAGETABLE_PMD_FOLDED
	pt_ops.alloc_pmd = alloc_pmd_early;
	pt_ops.get_pmd_virt = get_pmd_virt_early;
#endif
	/* Setup early PGD for fixmap */
	create_pgd_mapping(early_pg_dir, FIXADDR_START,
			   (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);

#ifndef __PAGETABLE_PMD_FOLDED
	/* Setup fixmap PMD */
	create_pmd_mapping(fixmap_pmd, FIXADDR_START,
			   (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
	/* Setup trampoline PGD and PMD */
	create_pgd_mapping(trampoline_pg_dir, kernel_map.virt_addr,
			   (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
#ifdef CONFIG_XIP_KERNEL
	create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr,
			   kernel_map.xiprom, PMD_SIZE, PAGE_KERNEL_EXEC);
#else
	create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr,
			   kernel_map.phys_addr, PMD_SIZE, PAGE_KERNEL_EXEC);
#endif
#else
	/* Setup trampoline PGD */
	create_pgd_mapping(trampoline_pg_dir, kernel_map.virt_addr,
			   kernel_map.phys_addr, PGDIR_SIZE, PAGE_KERNEL_EXEC);
#endif

	/*
	 * Setup early PGD covering entire kernel which will allow
	 * us to reach paging_init(). We map all memory banks later
	 * in setup_vm_final() below.
	 */
	create_kernel_page_table(early_pg_dir, true);

	/* Setup early mapping for FDT early scan */
	create_fdt_early_page_table(early_pg_dir, dtb_pa);

	/*
	 * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
	 * range can not span multiple pmds.
	 */
	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));

#ifndef __PAGETABLE_PMD_FOLDED
	/*
	 * Early ioremap fixmap is already created as it lies within first 2MB
	 * of fixmap region. We always map PMD_SIZE. Thus, both FIX_BTMAP_END
	 * FIX_BTMAP_BEGIN should lie in the same pmd. Verify that and warn
	 * the user if not.
	 */
	fix_bmap_spmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_BEGIN))];
	fix_bmap_epmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_END))];
	if (pmd_val(fix_bmap_spmd) != pmd_val(fix_bmap_epmd)) {
		WARN_ON(1);
		pr_warn("fixmap btmap start [%08lx] != end [%08lx]\n",
			pmd_val(fix_bmap_spmd), pmd_val(fix_bmap_epmd));
		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
			fix_to_virt(FIX_BTMAP_BEGIN));
		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
			fix_to_virt(FIX_BTMAP_END));

		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
		pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
	}
#endif
}