arch/x86_64-pc/kernel/smpbootstrap.c

   1 #include "../bootstrap/cpu.h"
   2
   3 extern const struct {
   4     unsigned short size __attribute__((packed));
   5     unsigned long addr __attribute__((packed));
   6 } smp_gdt64_sel;
   7
   8 extern const struct {
   9     void *target_ip __attribute__((packed));
  10     unsigned short target_sel __attribute__((packed));
  11 } smp_kernel_target;
  12
  13 extern unsigned long smp_mmu, smp_arg1, smp_arg2, smp_arg3, smp_arg4, smp_baseaddr, smp_sp, smp_ip;
  14
  15 asm (".code16           \n"
  16 "       .type   smpbootstrap_0,@function \n"
  17 "smpbootstrap_0:                \n"
  18 "       cli                     \n"
  19 "       /* The config variables will be passed here... Do not execute them */ \n"
  20 "       jmp 1f                  \n"
  21 "                               \n"
  22 "               .align 4        \n"
  23 "smp_arg1:      .long 0         \n"     /* 0x0004 */
  24 "smp_arg2:      .long 0         \n"     /* 0x0008 */
  25 "smp_arg3:      .long 0         \n"     /* 0x000c */
  26 "smp_arg4:      .long 0         \n"     /* 0x0010 */
  27 "smp_mmu:       .long 0         \n"     /* 0x0014 */
  28 "smp_sp:        .long 0; .long 0 \n"    /* 0x0018 */
  29 "smp_ip:        .long 0; .long 0 \n"    /* 0x0020 */
  30 "smp_baseaddr:  .long 0         \n"
  31 "smp_gdt:       .short 0; .short 0; .short 0; .short 0 \n"
  32 "               .short 0x1000; .short 0x0000; .short 0x9a00; .short 0x0040 \n"
  33 "               .short 0x1000; .short 0x0000; .short 0x9200; .short 0x0040 \n"
  34 "smp_gdt64:     .short 0; .short 0; .short 0; .short 0 \n"
  35 "               .short 0xffff; .short 0x0000; .short 0x9a00; .short 0x00af \n"
  36 "               .short 0xffff; .short 0x0000; .short 0x9200; .short 0x00af \n"
  37 "smp_gdt_sel:   .short 23       \n"
  38 "               .long 0         \n"
  39 "smp_gdt64_sel: .short 23       \n"
  40 "               .long 0         \n"
  41 "smp_kernel_target: .long 0; .short 8\n"
  42 "                               \n"
  43 "1:                             \n"
  44 "       mov %cs,%ax             \n"     /* Find out where the code resides */
  45 "       shl $4, %eax            \n"
  46 "       movl %eax,%cs:smp_baseaddr \n"  /* Store base address of the trampoline */
  47 "       leal smp_gdt(%eax), %ebx \n"    /* Load physical address of 32-bit gdt */
  48 "       movl %ebx, %cs:smp_gdt_sel+2\n" /* Set up 32-bit gdt address */
  49 "       leal smp_gdt64(%eax), %ebx \n"  /* Load physical address of 64-bit gdt */
  50 "       movl %ebx, %cs:smp_gdt64_sel+2\n"       /* Set up 64-bit gdt address */
  51 "       leal boot64(%eax), %ebx \n"     /* Load physical address of 64-bit code */
  52 "       movl %ebx, %cs:smp_kernel_target \n"    /* Set up 64-bit entry address */
  53 "       movw %ax, %cs:smp_gdt+10 \n"    /* Set base address of 32-bit code segment (bits 0:15) */
  54 "       movw %ax, %cs:smp_gdt+18 \n"    /* Set base address of 32-bit data segment (bits 0:15) */
  55 "       shr $16, %eax           \n"
  56 "       movb %al, %cs:smp_gdt+12 \n"    /* Set base address of 32-bit code segment (bits 16:23) */
  57 "       movb %al, %cs:smp_gdt+20 \n"    /* Set base address of 32-bit data segment (bits 16:23) */
  58 "       ADDR32 DATA32 lgdt %cs:smp_gdt_sel    \n"     /* Load gdt */
  59 "                               \n"
  60 "       movw $0x3f8,%dx         \n"
  61 "       movb $'x',%al           \n"
  62 "       outb %al,%dx            \n"
  63 "                               \n"
  64 "       movl %cr0,%eax          \n"     /* Enter protected mode */
  65 "       orb $1,%al              \n"
  66 "       movl %eax,%cr0          \n"
  67 "                               \n"
  68 "       ljmp $0x8,$2f   /* Please note that the %cs segment selector has to have it's base address properly adjusted */ \n"
  69 "                               \n"
  70 "       .code32                 \n"
  71 "2:     movw $0x10,%ax          \n"     /* Setup the 32-bit data selectors */
  72 "       movw %ax,%ds            \n"
  73 "       movw %ax,%es            \n"
  74 "       movw %ax,%ss            \n"
  75 "       movl $4096-4,%esp       \n"     /* Stack at the top of this 4K page */
  76 "                               \n"
  77 "       jmp smp_c_trampoline    \n");
  78
  79 /*
  80  * This tiny procedure sets the complete 64-bit environment up - it loads the descriptors,
  81  * enables 64-bit mode, loads MMU tables and trhough paging it activates the 64-bit long mode.
  82  *
  83  * After that it is perfectly safe to jump into the pure 64-bit kernel.
  84  */
  85 static void leave_32bit_mode()
  86 {
  87     unsigned int v1, v2, v3, v4;
  88     asm volatile ("lgdt %0"::"m"(smp_gdt64_sel));
  89
  90     asm volatile ("outb %b0,%w1"::"a"('b'),"Nd"(0x3f8));
  91
  92     /* Enable PAE */
  93     wrcr(cr4, _CR4_PAE | _CR4_PGE);
  94
  95     asm volatile ("outb %b0,%w1"::"a"('c'),"Nd"(0x3f8));
  96
  97     /* enable pages */
  98     wrcr(cr3, smp_mmu);
  99
 100     asm volatile ("outb %b0,%w1"::"a"('d'),"Nd"(0x3f8));
 101
 102     /* enable long mode */
 103     rdmsr(EFER, &v1, &v2);
 104     v1 |= _EFER_LME;
 105     wrmsr(EFER, v1, v2);
 106
 107     asm volatile ("outb %b0,%w1"::"a"('e'),"Nd"(0x3f8));
 108
 109     /* enable paging and activate long mode */
 110     wrcr(cr0, _CR0_PG | _CR0_PE);
 111 }
 112 static void __attribute__((used, noreturn)) smp_c_trampoline()
 113 {
 114     asm volatile ("outb %b0,%w1"::"a"('a'),"Nd"(0x3f8));
 115     leave_32bit_mode();
 116
 117     asm volatile ("outb %b0,%w1"::"a"('f'),"Nd"(0x3f8));
 118
 119     asm volatile("ljmp *%0"::"m"(smp_kernel_target),"b"(smp_baseaddr),"D"(smp_arg1),"S"(smp_arg2),"d"(smp_arg3),"c"(smp_arg4));
 120     while(1);
 121 }
 122
 123 asm (".code64\n"
 124 "boot64:        \n"
 125 "       mov $0x10,%ax   \n"
 126 "       mov %ax,%ds     \n"
 127 "       mov %ax,%es     \n"
 128 "       mov %ax,%ss     \n"
 129 "       movq 0x18(%rbx), %rsp \n"
 130 "       movq 0x20(%rbx), %rax \n"
 131 "       jmp *%rax \n"
 132 "1:       hlt; jmp 1b       \n"
 133 "       .code32\n"
 134 );