diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-07-08 09:43:01 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-07-08 09:43:01 +0200 |
commit | 3c1ca43fafea41e38cb2d0c1684119af4c1de547 (patch) | |
tree | 122e41a7b9fca26ea25ea9864180f5016274a8c8 /arch/x86 | |
parent | 6924d1ab8b7bbe5ab416713f5701b3316b2df85b (diff) | |
parent | 6bcb13b35a2ea39be6c7cc0292b8ad1191b1a748 (diff) |
Merge branch 'x86/setup' into x86/devel
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/Kconfig.debug | 8 | ||||
-rw-r--r-- | arch/x86/boot/a20.c | 5 | ||||
-rw-r--r-- | arch/x86/boot/compressed/misc.c | 55 | ||||
-rw-r--r-- | arch/x86/boot/compressed/relocs.c | 198 | ||||
-rw-r--r-- | arch/x86/boot/cpu.c | 2 | ||||
-rw-r--r-- | arch/x86/boot/main.c | 4 | ||||
-rw-r--r-- | arch/x86/boot/pmjump.S | 4 |
7 files changed, 162 insertions, 114 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 18363374d51a..38a15333f725 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -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 diff --git a/arch/x86/boot/a20.c b/arch/x86/boot/a20.c index e01aafd03bde..4063d630deff 100644 --- a/arch/x86/boot/a20.c +++ b/arch/x86/boot/a20.c @@ -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) diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 90456cee47c3..11629e903aa5 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -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; +#ifndef CONFIG_X86_VERBOSE_BOOTUP + if (!error) + return; +#endif + #ifdef CONFIG_X86_32 - if (RM_SCREEN_INFO.orig_video_mode == 0 && lines == 0 && cols == 0) + if (real_mode->screen_info.orig_video_mode == 0 && + lines == 0 && cols == 0) return; #endif - x = RM_SCREEN_INFO.orig_x; - y = RM_SCREEN_INFO.orig_y; + 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"); @@ -395,7 +398,8 @@ static void parse_elf(void *output) return; } - putstr("Parsing ELF... "); + if (!quiet) + putstr("Parsing ELF... "); phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum); if (!phdrs) @@ -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(); - putstr("\nDecompressing Linux... "); + if (!quiet) + putstr("\nDecompressing Linux... "); gunzip(); parse_elf(output); - putstr("done.\nBooting the kernel.\n"); + if (!quiet) + putstr("done.\nBooting the kernel.\n"); return; } diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c index edaadea90aaf..a1310c52fc0c 100644 --- a/arch/x86/boot/compressed/relocs.c +++ b/arch/x86/boot/compressed/relocs.c @@ -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 @@ -35,7 +39,7 @@ static int is_safe_abs_reloc(const char* sym_name) { int i; - for(i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) { + for (i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) { if (!strcmp(sym_name, safe_abs_relocs[i])) /* Match found */ return 1; @@ -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); + for (i = 0; i < ehdr.e_shnum; i++) { + 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]; } } @@ -274,20 +283,22 @@ static void read_shdrs(FILE *fp) static void read_strtabs(FILE *fp) { int i; - for(i = 0; i < ehdr.e_shnum; i++) { - if (shdr[i].sh_type != SHT_STRTAB) { + for (i = 0; i < ehdr.e_shnum; i++) { + 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)); } @@ -297,28 +308,31 @@ static void read_strtabs(FILE *fp) static void read_symtabs(FILE *fp) { int i,j; - for(i = 0; i < ehdr.e_shnum; i++) { - if (shdr[i].sh_type != SHT_SYMTAB) { + for (i = 0; i < ehdr.e_shnum; i++) { + 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); } } } @@ -327,26 +341,29 @@ static void read_symtabs(FILE *fp) static void read_relocs(FILE *fp) { int i,j; - for(i = 0; i < ehdr.e_shnum; i++) { - if (shdr[i].sh_type != SHT_REL) { + for (i = 0; i < ehdr.e_shnum; i++) { + 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); } } } @@ -357,19 +374,21 @@ static void print_absolute_symbols(void) int i; printf("Absolute symbols\n"); printf(" Num: Value Size Type Bind Visibility Name\n"); - for(i = 0; i < ehdr.e_shnum; i++) { + 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; @@ -389,26 +408,27 @@ static void print_absolute_relocs(void) { int i, printed = 0; - for(i = 0; i < ehdr.e_shnum; i++) { + 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) { @@ -456,26 +476,28 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym)) { int i; /* Walk through the relocations */ - for(i = 0; i < ehdr.e_shnum; i++) { + 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 */ @@ -539,7 +561,7 @@ static void emit_relocs(int as_text) */ printf(".section \".data.reloc\",\"a\"\n"); printf(".balign 4\n"); - for(i = 0; i < reloc_count; i++) { + for (i = 0; i < reloc_count; i++) { printf("\t .long 0x%08lx\n", relocs[i]); } printf("\n"); @@ -550,7 +572,7 @@ static void emit_relocs(int as_text) /* Print a stop */ printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]); /* Now print each relocation */ - for(i = 0; i < reloc_count; i++) { + for (i = 0; i < reloc_count; i++) { buf[0] = (relocs[i] >> 0) & 0xff; buf[1] = (relocs[i] >> 8) & 0xff; buf[2] = (relocs[i] >> 16) & 0xff; @@ -577,7 +599,7 @@ int main(int argc, char **argv) show_absolute_relocs = 0; as_text = 0; fname = NULL; - for(i = 1; i < argc; i++) { + for (i = 1; i < argc; i++) { char *arg = argv[i]; if (*arg == '-') { if (strcmp(argv[1], "--abs-syms") == 0) { diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c index 00e19edd852c..92d6fd73dc7d 100644 --- a/arch/x86/boot/cpu.c +++ b/arch/x86/boot/cpu.c @@ -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; } diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c index 77569a4a3be1..2296164b54d2 100644 --- a/arch/x86/boot/main.c +++ b/arch/x86/boot/main.c @@ -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(); } diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S index ab049d40a884..141b6e20ed31 100644 --- a/arch/x86/boot/pmjump.S +++ b/arch/x86/boot/pmjump.S @@ -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 |