Merge branch 'x86/setup' into x86/devel

This commit is contained in:
Ingo Molnar 2008-07-08 09:43:01 +02:00
commit 3c1ca43faf
20 changed files with 210 additions and 148 deletions

View file

@ -1,17 +1,14 @@
THE LINUX/I386 BOOT PROTOCOL
----------------------------
THE LINUX/x86 BOOT PROTOCOL
---------------------------
H. Peter Anvin <hpa@zytor.com>
Last update 2007-05-23
On the i386 platform, the Linux kernel uses a rather complicated boot
On the x86 platform, the Linux kernel uses a rather complicated boot
convention. This has evolved partially due to historical aspects, as
well as the desire in the early days to have the kernel itself be a
bootable image, the complicated PC memory model and due to changed
expectations in the PC industry caused by the effective demise of
real-mode DOS as a mainstream operating system.
Currently, the following versions of the Linux/i386 boot protocol exist.
Currently, the following versions of the Linux/x86 boot protocol exist.
Old kernels: zImage/Image support only. Some very early kernels
may not even support a command line.
@ -372,10 +369,17 @@ Protocol: 2.00+
- If 0, the protected-mode code is loaded at 0x10000.
- If 1, the protected-mode code is loaded at 0x100000.
Bit 5 (write): QUIET_FLAG
- If 0, print early messages.
- If 1, suppress early messages.
This requests to the kernel (decompressor and early
kernel) to not write early messages that require
accessing the display hardware directly.
Bit 6 (write): KEEP_SEGMENTS
Protocol: 2.07+
- if 0, reload the segment registers in the 32bit entry point.
- if 1, do not reload the segment registers in the 32bit entry point.
- If 0, reload the segment registers in the 32bit entry point.
- If 1, do not reload the segment registers in the 32bit entry point.
Assume that %cs %ds %ss %es are all set to flat segments with
a base of 0 (or the equivalent for their environment).
@ -504,7 +508,7 @@ Protocol: 2.06+
maximum size was 255.
Field name: hardware_subarch
Type: write
Type: write (optional, defaults to x86/PC)
Offset/size: 0x23c/4
Protocol: 2.07+
@ -520,11 +524,13 @@ Protocol: 2.07+
0x00000002 Xen
Field name: hardware_subarch_data
Type: write
Type: write (subarch-dependent)
Offset/size: 0x240/8
Protocol: 2.07+
A pointer to data that is specific to hardware subarch
This field is currently unused for the default x86/PC environment,
do not modify.
Field name: payload_offset
Type: read
@ -545,6 +551,34 @@ Protocol: 2.08+
The length of the payload.
Field name: setup_data
Type: write (special)
Offset/size: 0x250/8
Protocol: 2.09+
The 64-bit physical pointer to NULL terminated single linked list of
struct setup_data. This is used to define a more extensible boot
parameters passing mechanism. The definition of struct setup_data is
as follow:
struct setup_data {
u64 next;
u32 type;
u32 len;
u8 data[0];
};
Where, the next is a 64-bit physical pointer to the next node of
linked list, the next field of the last node is 0; the type is used
to identify the contents of data; the len is the length of data
field; the data holds the real payload.
This list may be modified at a number of points during the bootup
process. Therefore, when modifying this list one should always make
sure to consider the case where the linked list already contains
entries.
**** THE IMAGE CHECKSUM
From boot protocol version 2.08 onwards the CRC-32 is calculated over
@ -553,6 +587,7 @@ initial remainder of 0xffffffff. The checksum is appended to the
file; therefore the CRC of the file up to the limit specified in the
syssize field of the header is always 0.
**** THE KERNEL COMMAND LINE
The kernel command line has become an important way for the boot
@ -584,28 +619,6 @@ command line is entered using the following protocol:
covered by setup_move_size, so you may need to adjust this
field.
Field name: setup_data
Type: write (obligatory)
Offset/size: 0x250/8
Protocol: 2.09+
The 64-bit physical pointer to NULL terminated single linked list of
struct setup_data. This is used to define a more extensible boot
parameters passing mechanism. The definition of struct setup_data is
as follow:
struct setup_data {
u64 next;
u32 type;
u32 len;
u8 data[0];
};
Where, the next is a 64-bit physical pointer to the next node of
linked list, the next field of the last node is 0; the type is used
to identify the contents of data; the len is the length of data
field; the data holds the real payload.
**** MEMORY LAYOUT OF THE REAL-MODE CODE

View file

@ -20,6 +20,14 @@ config NONPROMISC_DEVMEM
If in doubt, say Y.
config X86_VERBOSE_BOOTUP
bool "Enable verbose x86 bootup info messages"
default y
help
Enables the informational output from the decompression stage
(e.g. bzImage) of the boot. If you disable this you will still
see errors. Disable this if you want silent bootup.
config EARLY_PRINTK
bool "Early printk" if EMBEDDED
default y

View file

@ -1,7 +1,7 @@
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
* Copyright 2007-2008 rPath, Inc. - All Rights Reserved
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
@ -95,6 +95,9 @@ static void enable_a20_kbc(void)
outb(0xdf, 0x60); /* A20 on */
empty_8042();
outb(0xff, 0x64); /* Null command, but UHCI wants it */
empty_8042();
}
static void enable_a20_fast(void)

View file

@ -30,6 +30,7 @@
#include <asm/io.h>
#include <asm/page.h>
#include <asm/boot.h>
#include <asm/bootparam.h>
/* WARNING!!
* This code is compiled with -fPIC and it is relocated dynamically
@ -187,13 +188,8 @@ static void gzip_release(void **);
/*
* This is set up by the setup-routine at boot-time
*/
static unsigned char *real_mode; /* Pointer to real-mode data */
#define RM_EXT_MEM_K (*(unsigned short *)(real_mode + 0x2))
#ifndef STANDARD_MEMORY_BIOS_CALL
#define RM_ALT_MEM_K (*(unsigned long *)(real_mode + 0x1e0))
#endif
#define RM_SCREEN_INFO (*(struct screen_info *)(real_mode+0))
static struct boot_params *real_mode; /* Pointer to real-mode data */
static int quiet;
extern unsigned char input_data[];
extern int input_len;
@ -206,7 +202,8 @@ static void free(void *where);
static void *memset(void *s, int c, unsigned n);
static void *memcpy(void *dest, const void *src, unsigned n);
static void putstr(const char *);
static void __putstr(int, const char *);
#define putstr(__x) __putstr(0, __x)
#ifdef CONFIG_X86_64
#define memptr long
@ -270,18 +267,24 @@ static void scroll(void)
vidmem[i] = ' ';
}
static void putstr(const char *s)
static void __putstr(int error, const char *s)
{
int x, y, pos;
char c;
#ifdef CONFIG_X86_32
if (RM_SCREEN_INFO.orig_video_mode == 0 && lines == 0 && cols == 0)
#ifndef CONFIG_X86_VERBOSE_BOOTUP
if (!error)
return;
#endif
x = RM_SCREEN_INFO.orig_x;
y = RM_SCREEN_INFO.orig_y;
#ifdef CONFIG_X86_32
if (real_mode->screen_info.orig_video_mode == 0 &&
lines == 0 && cols == 0)
return;
#endif
x = real_mode->screen_info.orig_x;
y = real_mode->screen_info.orig_y;
while ((c = *s++) != '\0') {
if (c == '\n') {
@ -302,8 +305,8 @@ static void putstr(const char *s)
}
}
RM_SCREEN_INFO.orig_x = x;
RM_SCREEN_INFO.orig_y = y;
real_mode->screen_info.orig_x = x;
real_mode->screen_info.orig_y = y;
pos = (x + cols * y) * 2; /* Update cursor position */
outb(14, vidport);
@ -366,9 +369,9 @@ static void flush_window(void)
static void error(char *x)
{
putstr("\n\n");
putstr(x);
putstr("\n\n -- System halted");
__putstr(1, "\n\n");
__putstr(1, x);
__putstr(1, "\n\n -- System halted");
while (1)
asm("hlt");
@ -395,6 +398,7 @@ static void parse_elf(void *output)
return;
}
if (!quiet)
putstr("Parsing ELF... ");
phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
@ -430,7 +434,10 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
{
real_mode = rmode;
if (RM_SCREEN_INFO.orig_video_mode == 7) {
if (real_mode->hdr.loadflags & QUIET_FLAG)
quiet = 1;
if (real_mode->screen_info.orig_video_mode == 7) {
vidmem = (char *) 0xb0000;
vidport = 0x3b4;
} else {
@ -438,8 +445,8 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
vidport = 0x3d4;
}
lines = RM_SCREEN_INFO.orig_video_lines;
cols = RM_SCREEN_INFO.orig_video_cols;
lines = real_mode->screen_info.orig_video_lines;
cols = real_mode->screen_info.orig_video_cols;
window = output; /* Output buffer (Normally at 1M) */
free_mem_ptr = heap; /* Heap */
@ -465,9 +472,11 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
#endif
makecrc();
if (!quiet)
putstr("\nDecompressing Linux... ");
gunzip();
parse_elf(output);
if (!quiet)
putstr("done.\nBooting the kernel.\n");
return;
}

View file

@ -10,16 +10,20 @@
#define USE_BSD
#include <endian.h>
#define MAX_SHDRS 100
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
static Elf32_Ehdr ehdr;
static Elf32_Shdr shdr[MAX_SHDRS];
static Elf32_Sym *symtab[MAX_SHDRS];
static Elf32_Rel *reltab[MAX_SHDRS];
static char *strtab[MAX_SHDRS];
static unsigned long reloc_count, reloc_idx;
static unsigned long *relocs;
struct section {
Elf32_Shdr shdr;
struct section *link;
Elf32_Sym *symtab;
Elf32_Rel *reltab;
char *strtab;
};
static struct section *secs;
/*
* Following symbols have been audited. There values are constant and do
* not change if bzImage is loaded at a different physical address than
@ -137,10 +141,10 @@ static const char *sec_name(unsigned shndx)
{
const char *sec_strtab;
const char *name;
sec_strtab = strtab[ehdr.e_shstrndx];
sec_strtab = secs[ehdr.e_shstrndx].strtab;
name = "<noname>";
if (shndx < ehdr.e_shnum) {
name = sec_strtab + shdr[shndx].sh_name;
name = sec_strtab + secs[shndx].shdr.sh_name;
}
else if (shndx == SHN_ABS) {
name = "ABSOLUTE";
@ -159,7 +163,7 @@ static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
name = sym_strtab + sym->st_name;
}
else {
name = sec_name(shdr[sym->st_shndx].sh_name);
name = sec_name(secs[sym->st_shndx].shdr.sh_name);
}
return name;
}
@ -244,29 +248,34 @@ static void read_ehdr(FILE *fp)
static void read_shdrs(FILE *fp)
{
int i;
if (ehdr.e_shnum > MAX_SHDRS) {
die("%d section headers supported: %d\n",
ehdr.e_shnum, MAX_SHDRS);
Elf32_Shdr shdr;
secs = calloc(ehdr.e_shnum, sizeof(struct section));
if (!secs) {
die("Unable to allocate %d section headers\n",
ehdr.e_shnum);
}
if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
ehdr.e_shoff, strerror(errno));
}
if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
die("Cannot read ELF section headers: %s\n",
strerror(errno));
}
for (i = 0; i < ehdr.e_shnum; i++) {
shdr[i].sh_name = elf32_to_cpu(shdr[i].sh_name);
shdr[i].sh_type = elf32_to_cpu(shdr[i].sh_type);
shdr[i].sh_flags = elf32_to_cpu(shdr[i].sh_flags);
shdr[i].sh_addr = elf32_to_cpu(shdr[i].sh_addr);
shdr[i].sh_offset = elf32_to_cpu(shdr[i].sh_offset);
shdr[i].sh_size = elf32_to_cpu(shdr[i].sh_size);
shdr[i].sh_link = elf32_to_cpu(shdr[i].sh_link);
shdr[i].sh_info = elf32_to_cpu(shdr[i].sh_info);
shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
shdr[i].sh_entsize = elf32_to_cpu(shdr[i].sh_entsize);
struct section *sec = &secs[i];
if (fread(&shdr, sizeof shdr, 1, fp) != 1)
die("Cannot read ELF section headers %d/%d: %s\n",
i, ehdr.e_shnum, strerror(errno));
sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name);
sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type);
sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags);
sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr);
sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset);
sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size);
sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link);
sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info);
sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize);
if (sec->shdr.sh_link < ehdr.e_shnum)
sec->link = &secs[sec->shdr.sh_link];
}
}
@ -275,19 +284,21 @@ static void read_strtabs(FILE *fp)
{
int i;
for (i = 0; i < ehdr.e_shnum; i++) {
if (shdr[i].sh_type != SHT_STRTAB) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_STRTAB) {
continue;
}
strtab[i] = malloc(shdr[i].sh_size);
if (!strtab[i]) {
sec->strtab = malloc(sec->shdr.sh_size);
if (!sec->strtab) {
die("malloc of %d bytes for strtab failed\n",
shdr[i].sh_size);
sec->shdr.sh_size);
}
if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
shdr[i].sh_offset, strerror(errno));
sec->shdr.sh_offset, strerror(errno));
}
if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
!= sec->shdr.sh_size) {
die("Cannot read symbol table: %s\n",
strerror(errno));
}
@ -298,27 +309,30 @@ static void read_symtabs(FILE *fp)
{
int i,j;
for (i = 0; i < ehdr.e_shnum; i++) {
if (shdr[i].sh_type != SHT_SYMTAB) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_SYMTAB) {
continue;
}
symtab[i] = malloc(shdr[i].sh_size);
if (!symtab[i]) {
sec->symtab = malloc(sec->shdr.sh_size);
if (!sec->symtab) {
die("malloc of %d bytes for symtab failed\n",
shdr[i].sh_size);
sec->shdr.sh_size);
}
if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
shdr[i].sh_offset, strerror(errno));
sec->shdr.sh_offset, strerror(errno));
}
if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
!= sec->shdr.sh_size) {
die("Cannot read symbol table: %s\n",
strerror(errno));
}
for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
symtab[i][j].st_name = elf32_to_cpu(symtab[i][j].st_name);
symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
symtab[i][j].st_size = elf32_to_cpu(symtab[i][j].st_size);
symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
Elf32_Sym *sym = &sec->symtab[j];
sym->st_name = elf32_to_cpu(sym->st_name);
sym->st_value = elf32_to_cpu(sym->st_value);
sym->st_size = elf32_to_cpu(sym->st_size);
sym->st_shndx = elf16_to_cpu(sym->st_shndx);
}
}
}
@ -328,25 +342,28 @@ static void read_relocs(FILE *fp)
{
int i,j;
for (i = 0; i < ehdr.e_shnum; i++) {
if (shdr[i].sh_type != SHT_REL) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL) {
continue;
}
reltab[i] = malloc(shdr[i].sh_size);
if (!reltab[i]) {
sec->reltab = malloc(sec->shdr.sh_size);
if (!sec->reltab) {
die("malloc of %d bytes for relocs failed\n",
shdr[i].sh_size);
sec->shdr.sh_size);
}
if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
die("Seek to %d failed: %s\n",
shdr[i].sh_offset, strerror(errno));
sec->shdr.sh_offset, strerror(errno));
}
if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
!= sec->shdr.sh_size) {
die("Cannot read symbol table: %s\n",
strerror(errno));
}
for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
reltab[i][j].r_info = elf32_to_cpu(reltab[i][j].r_info);
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
Elf32_Rel *rel = &sec->reltab[j];
rel->r_offset = elf32_to_cpu(rel->r_offset);
rel->r_info = elf32_to_cpu(rel->r_info);
}
}
}
@ -358,18 +375,20 @@ static void print_absolute_symbols(void)
printf("Absolute symbols\n");
printf(" Num: Value Size Type Bind Visibility Name\n");
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
char *sym_strtab;
Elf32_Sym *sh_symtab;
int j;
if (shdr[i].sh_type != SHT_SYMTAB) {
if (sec->shdr.sh_type != SHT_SYMTAB) {
continue;
}
sh_symtab = symtab[i];
sym_strtab = strtab[shdr[i].sh_link];
for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
sh_symtab = sec->symtab;
sym_strtab = sec->link->strtab;
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
Elf32_Sym *sym;
const char *name;
sym = &symtab[i][j];
sym = &sec->symtab[j];
name = sym_name(sym_strtab, sym);
if (sym->st_shndx != SHN_ABS) {
continue;
@ -390,25 +409,26 @@ static void print_absolute_relocs(void)
int i, printed = 0;
for (i = 0; i < ehdr.e_shnum; i++) {
struct section *sec = &secs[i];
struct section *sec_applies, *sec_symtab;
char *sym_strtab;
Elf32_Sym *sh_symtab;
unsigned sec_applies, sec_symtab;
int j;
if (shdr[i].sh_type != SHT_REL) {
if (sec->shdr.sh_type != SHT_REL) {
continue;
}
sec_symtab = shdr[i].sh_link;
sec_applies = shdr[i].sh_info;
if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
sec_symtab = sec->link;
sec_applies = &secs[sec->shdr.sh_info];
if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
continue;
}
sh_symtab = symtab[sec_symtab];
sym_strtab = strtab[shdr[sec_symtab].sh_link];
for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
sh_symtab = sec_symtab->symtab;
sym_strtab = sec_symtab->link->strtab;
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
Elf32_Rel *rel;
Elf32_Sym *sym;
const char *name;
rel = &reltab[i][j];
rel = &sec->reltab[j];
sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
name = sym_name(sym_strtab, sym);
if (sym->st_shndx != SHN_ABS) {
@ -459,23 +479,25 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
for (i = 0; i < ehdr.e_shnum; i++) {
char *sym_strtab;
Elf32_Sym *sh_symtab;
unsigned sec_applies, sec_symtab;
struct section *sec_applies, *sec_symtab;
int j;
if (shdr[i].sh_type != SHT_REL) {
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL) {
continue;
}
sec_symtab = shdr[i].sh_link;
sec_applies = shdr[i].sh_info;
if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
sec_symtab = sec->link;
sec_applies = &secs[sec->shdr.sh_info];
if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
continue;
}
sh_symtab = symtab[sec_symtab];
sym_strtab = strtab[shdr[sec_symtab].sh_link];
for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
sh_symtab = sec_symtab->symtab;
sym_strtab = sec->link->strtab;
for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
Elf32_Rel *rel;
Elf32_Sym *sym;
unsigned r_type;
rel = &reltab[i][j];
rel = &sec->reltab[j];
sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
r_type = ELF32_R_TYPE(rel->r_info);
/* Don't visit relocations to absolute symbols */

View file

@ -28,6 +28,8 @@ static char *cpu_name(int level)
if (level == 64) {
return "x86-64";
} else {
if (level == 15)
level = 6;
sprintf(buf, "i%d86", level);
return buf;
}

View file

@ -165,6 +165,10 @@ void main(void)
/* Set the video mode */
set_video();
/* Parse command line for 'quiet' and pass it to decompressor. */
if (cmdline_find_option_bool("quiet"))
boot_params.hdr.loadflags |= QUIET_FLAG;
/* Do the last things and invoke protected mode */
go_to_protected_mode();
}

View file

@ -33,6 +33,8 @@ protected_mode_jump:
movw %cs, %bx
shll $4, %ebx
addl %ebx, 2f
jmp 1f # Short jump to serialize on 386/486
1:
movw $__BOOT_DS, %cx
movw $__BOOT_TSS, %di
@ -40,8 +42,6 @@ protected_mode_jump:
movl %cr0, %edx
orb $X86_CR0_PE, %dl # Protected mode
movl %edx, %cr0
jmp 1f # Short jump to serialize on 386/486
1:
# Transition to 32-bit mode
.byte 0x66, 0xea # ljmpl opcode

View file

@ -40,6 +40,7 @@ struct setup_header {
__u8 type_of_loader;
__u8 loadflags;
#define LOADED_HIGH (1<<0)
#define QUIET_FLAG (1<<5)
#define KEEP_SEGMENTS (1<<6)
#define CAN_USE_HEAP (1<<7)
__u16 setup_move_size;