Commit efe659ac authored by Mike Rapoport (Microsoft)'s avatar Mike Rapoport (Microsoft) Committed by Ingo Molnar
Browse files

x86/e820: Drop obsolete E820_TYPE_RESERVED_KERN and related code 



E820_TYPE_RESERVED_KERN is a relict from the ancient history that was used
to early reserve setup_data, see:

  28bb2237 ("x86: move reserve_setup_data to setup.c")

Nowadays setup_data is anyway reserved in memblock and there is no point in
carrying E820_TYPE_RESERVED_KERN that behaves exactly like E820_TYPE_RAM
but only complicates the code.

A bonus for removing E820_TYPE_RESERVED_KERN is a small but measurable
speedup of 20 microseconds in init_mem_mappings() on a VM with 32GB or RAM.

Signed-off-by: default avatarMike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20250214090651.3331663-5-rppt@kernel.org
parent d45dd0a9

arch/x86/include/asm/e820/api.h

+0 −1
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ extern unsigned long e820__end_of_low_ram_pfn(void); 
extern u64  e820__memblock_alloc_reserved(u64 size, u64 align);

extern void e820__memblock_setup(void);



extern void e820__reserve_setup_data(void);

extern void e820__finish_early_params(void);

extern void e820__reserve_resources(void);

extern void e820__reserve_resources_late(void);

arch/x86/include/asm/e820/types.h

+0 −9
Original line number Diff line number Diff line
@@ -35,15 +35,6 @@ enum e820_type { 
	 * marking it with the IORES_DESC_SOFT_RESERVED designation.

	 */

	E820_TYPE_SOFT_RESERVED	= 0xefffffff,



	/*

	 * Reserved RAM used by the kernel itself if

	 * CONFIG_INTEL_TXT=y is enabled, memory of this type

	 * will be included in the S3 integrity calculation

	 * and so should not include any memory that the BIOS

	 * might alter over the S3 transition:

	 */

	E820_TYPE_RESERVED_KERN	= 128,

};



/*

arch/x86/kernel/e820.c

+3 −62
Original line number Diff line number Diff line
@@ -187,8 +187,7 @@ void __init e820__range_add(u64 start, u64 size, enum e820_type type) 
static void __init e820_print_type(enum e820_type type)

{

	switch (type) {

	case E820_TYPE_RAM:		/* Fall through: */

	case E820_TYPE_RESERVED_KERN:	pr_cont("usable");			break;

	case E820_TYPE_RAM:		pr_cont("usable");			break;

	case E820_TYPE_RESERVED:	pr_cont("reserved");			break;

	case E820_TYPE_SOFT_RESERVED:	pr_cont("soft reserved");		break;

	case E820_TYPE_ACPI:		pr_cont("ACPI data");			break;
@@ -764,7 +763,7 @@ void __init e820__register_nosave_regions(unsigned long limit_pfn) 


		pfn = PFN_DOWN(entry->addr + entry->size);



		if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)

		if (entry->type != E820_TYPE_RAM)

			register_nosave_region(PFN_UP(entry->addr), pfn);



		if (pfn >= limit_pfn)
@@ -990,60 +989,6 @@ static int __init parse_memmap_opt(char *str) 
}

early_param("memmap", parse_memmap_opt);



/*

 * Reserve all entries from the bootloader's extensible data nodes list,

 * because if present we are going to use it later on to fetch e820

 * entries from it:

 */

void __init e820__reserve_setup_data(void)

{

	struct setup_indirect *indirect;

	struct setup_data *data;

	u64 pa_data, pa_next;

	u32 len;



	pa_data = boot_params.hdr.setup_data;

	if (!pa_data)

		return;



	while (pa_data) {

		data = early_memremap(pa_data, sizeof(*data));

		if (!data) {

			pr_warn("e820: failed to memremap setup_data entry\n");

			return;

		}



		len = sizeof(*data);

		pa_next = data->next;



		e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);



		if (data->type == SETUP_INDIRECT) {

			len += data->len;

			early_memunmap(data, sizeof(*data));

			data = early_memremap(pa_data, len);

			if (!data) {

				pr_warn("e820: failed to memremap indirect setup_data\n");

				return;

			}



			indirect = (struct setup_indirect *)data->data;



			if (indirect->type != SETUP_INDIRECT)

				e820__range_update(indirect->addr, indirect->len,

						   E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);

		}



		pa_data = pa_next;

		early_memunmap(data, len);

	}



	e820__update_table(e820_table);



	pr_info("extended physical RAM map:\n");

	e820__print_table("reserve setup_data");

}



/*

 * Called after parse_early_param(), after early parameters (such as mem=)

 * have been processed, in which case we already have an E820 table filled in
@@ -1063,7 +1008,6 @@ void __init e820__finish_early_params(void) 
static const char *__init e820_type_to_string(struct e820_entry *entry)

{

	switch (entry->type) {

	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */

	case E820_TYPE_RAM:		return "System RAM";

	case E820_TYPE_ACPI:		return "ACPI Tables";

	case E820_TYPE_NVS:		return "ACPI Non-volatile Storage";
@@ -1079,7 +1023,6 @@ static const char *__init e820_type_to_string(struct e820_entry *entry) 
static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry)

{

	switch (entry->type) {

	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */

	case E820_TYPE_RAM:		return IORESOURCE_SYSTEM_RAM;

	case E820_TYPE_ACPI:		/* Fall-through: */

	case E820_TYPE_NVS:		/* Fall-through: */
@@ -1101,7 +1044,6 @@ static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry) 
	case E820_TYPE_PRAM:		return IORES_DESC_PERSISTENT_MEMORY_LEGACY;

	case E820_TYPE_RESERVED:	return IORES_DESC_RESERVED;

	case E820_TYPE_SOFT_RESERVED:	return IORES_DESC_SOFT_RESERVED;

	case E820_TYPE_RESERVED_KERN:	/* Fall-through: */

	case E820_TYPE_RAM:		/* Fall-through: */

	case E820_TYPE_UNUSABLE:	/* Fall-through: */

	default:			return IORES_DESC_NONE;
@@ -1124,7 +1066,6 @@ static bool __init do_mark_busy(enum e820_type type, struct resource *res) 
	case E820_TYPE_PRAM:

	case E820_TYPE_PMEM:

		return false;

	case E820_TYPE_RESERVED_KERN:

	case E820_TYPE_RAM:

	case E820_TYPE_ACPI:

	case E820_TYPE_NVS:
@@ -1353,7 +1294,7 @@ void __init e820__memblock_setup(void) 
		if (entry->type == E820_TYPE_SOFT_RESERVED)

			memblock_reserve(entry->addr, entry->size);



		if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)

		if (entry->type != E820_TYPE_RAM)

			continue;



		memblock_add(entry->addr, entry->size);

arch/x86/kernel/setup.c

+0 −1
Original line number Diff line number Diff line
@@ -895,7 +895,6 @@ void __init setup_arch(char **cmdline_p) 
		setup_clear_cpu_cap(X86_FEATURE_APIC);

	}



	e820__reserve_setup_data();

	e820__finish_early_params();



	if (efi_enabled(EFI_BOOT))

arch/x86/kernel/tboot.c

+1 −2
Original line number Diff line number Diff line
@@ -200,8 +200,7 @@ static int tboot_setup_sleep(void) 
	tboot->num_mac_regions = 0;



	for (i = 0; i < e820_table->nr_entries; i++) {

		if ((e820_table->entries[i].type != E820_TYPE_RAM)

		 && (e820_table->entries[i].type != E820_TYPE_RESERVED_KERN))

		if (e820_table->entries[i].type != E820_TYPE_RAM)

			continue;



		add_mac_region(e820_table->entries[i].addr, e820_table->entries[i].size);