arch/x86/mm/pat/memtype.c

File Facts

System

Linux kernel

Corpus path

arch/x86/mm/pat/memtype.c

Extension

.c

Size

27817 bytes

Lines

1050

Domain

Architecture Layer

Bucket

arch/x86

Inferred role

Architecture Layer: operation-table or driver-model contract

Status

pattern implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

• CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/seq_file.h
• linux/memblock.h
• linux/debugfs.h
• linux/ioport.h
• linux/kernel.h
• linux/slab.h
• linux/io.h
• linux/mm.h
• linux/highmem.h
• linux/fs.h
• linux/rbtree.h
• linux/kvm_types.h
• asm/cpu_device_id.h
• asm/cacheflush.h
• asm/cacheinfo.h
• asm/processor.h
• asm/tlbflush.h
• asm/x86_init.h
• asm/fcntl.h
• asm/e820/api.h
• asm/mtrr.h
• asm/page.h
• asm/msr.h
• asm/memtype.h
• asm/io.h
• memtype.h
• ../mm_internal.h

Detected Declarations

• struct pagerange_state
• function pat_disable
• function nopat
• function pat_enabled
• function pat_debug_setup
• function get_page_memtype
• function set_page_memtype
• function get_page_memtype
• function set_page_memtype
• function init_cache_modes
• function pat_cpu_init
• function pat_cpu_init
• function pat_x_mtrr_type
• function pagerange_is_ram_callback
• function pat_pagerange_is_ram
• function reserve_ram_pages_type
• function free_ram_pages_type
• function sanitize_phys
• function memtype_reserve
• function memtype_free
• function lookup_memtype
• function pat_pfn_immune_to_uc_mtrr
• function memtype_reserve_io
• function memtype_free_io
• function arch_io_reserve_memtype_wc
• function arch_io_free_memtype_wc
• function phys_mem_access_prot
• function pgprot_set_cachemode
• function phys_mem_access_prot_allowed
• function memtype_kernel_map_sync
• function mapping
• function reserve_pfn_range
• function free_pfn_range
• function pfnmap_setup_cachemode
• function pfnmap_track
• function pfnmap_untrack
• function pgprot_writecombine
• function pgprot_writethrough
• function seq_start
• function memtype_seq_stop
• function memtype_seq_show
• function memtype_seq_open
• function pat_memtype_list_init
• export pat_enabled
• export arch_io_reserve_memtype_wc
• export arch_io_free_memtype_wc
• export pgprot_writecombine
• export pgprot_writethrough

Annotated Snippet

static const struct file_operations memtype_fops = {
	.open    = memtype_seq_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release,
};

static int __init pat_memtype_list_init(void)
{
	if (pat_enabled()) {
		debugfs_create_file("pat_memtype_list", S_IRUSR,
				    arch_debugfs_dir, NULL, &memtype_fops);
	}
	return 0;
}
late_initcall(pat_memtype_list_init);

#endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */

Annotation

• Immediate include surface: `linux/seq_file.h`, `linux/memblock.h`, `linux/debugfs.h`, `linux/ioport.h`, `linux/kernel.h`, `linux/slab.h`, `linux/io.h`, `linux/mm.h`.
• Detected declarations: `struct pagerange_state`, `function pat_disable`, `function nopat`, `function pat_enabled`, `function pat_debug_setup`, `function get_page_memtype`, `function set_page_memtype`, `function get_page_memtype`, `function set_page_memtype`, `function init_cache_modes`.
• Atlas domain: Architecture Layer / arch/x86.
• Implementation status: pattern implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.