diff options
| -rw-r--r-- | arch/x86/cpu/cpu.c | 82 |
1 files changed, 53 insertions, 29 deletions
diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c index 209ff29..8102fb9 100644 --- a/arch/x86/cpu/cpu.c +++ b/arch/x86/cpu/cpu.c @@ -55,35 +55,39 @@ struct gdt_ptr { u32 ptr; } __packed; -static void reload_gdt(void) +static void load_ds(u32 segment) { - /* - * There are machines which are known to not boot with the GDT - * being 8-byte unaligned. Intel recommends 16 byte alignment - */ - static const u64 boot_gdt[] __attribute__((aligned(16))) = { - /* CS: code, read/execute, 4 GB, base 0 */ - [X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff), - /* DS: data, read/write, 4 GB, base 0 */ - [X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff), - /* 16-bit CS: code, read/execute, 64 kB, base 0 */ - [X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff), - /* 16-bit DS: data, read/write, 64 kB, base 0 */ - [X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff), - }; - static struct gdt_ptr gdt; - - gdt.len = sizeof(boot_gdt)-1; - gdt.ptr = (u32)&boot_gdt; - - asm volatile("lgdtl %0\n" \ - "movl $((2+1)*8), %%ecx\n" \ - "movl %%ecx, %%ds\n" \ - "movl %%ecx, %%es\n" \ - "movl %%ecx, %%fs\n" \ - "movl %%ecx, %%gs\n" \ - "movl %%ecx, %%ss" \ - : : "m" (gdt) : "ecx"); + asm volatile("movl %0, %%ds" : : "r" (segment * X86_GDT_ENTRY_SIZE)); +} + +static void load_es(u32 segment) +{ + asm volatile("movl %0, %%es" : : "r" (segment * X86_GDT_ENTRY_SIZE)); +} + +static void load_fs(u32 segment) +{ + asm volatile("movl %0, %%fs" : : "r" (segment * X86_GDT_ENTRY_SIZE)); +} + +static void load_gs(u32 segment) +{ + asm volatile("movl %0, %%gs" : : "r" (segment * X86_GDT_ENTRY_SIZE)); +} + +static void load_ss(u32 segment) +{ + asm volatile("movl %0, %%ss" : : "r" (segment * X86_GDT_ENTRY_SIZE)); +} + +static void load_gdt(const u64 *boot_gdt, u16 num_entries) +{ + struct gdt_ptr gdt; + + gdt.len = (num_entries * 8) - 1; + gdt.ptr = (u32)boot_gdt; + + asm volatile("lgdtl %0\n" : : "m" (gdt)); } int x86_cpu_init_f(void) @@ -113,7 +117,27 @@ int x86_cpu_init_r(void) "movl %%eax, %%cr0\n" "wbinvd\n" : : "i" (nw_cd_rst) : "eax"); - reload_gdt(); + /* + * There are machines which are known to not boot with the GDT + * being 8-byte unaligned. Intel recommends 16 byte alignment + */ + static const u64 boot_gdt[] __aligned(16) = { + /* CS: code, read/execute, 4 GB, base 0 */ + [X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff), + /* DS: data, read/write, 4 GB, base 0 */ + [X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff), + /* 16-bit CS: code, read/execute, 64 kB, base 0 */ + [X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff), + /* 16-bit DS: data, read/write, 64 kB, base 0 */ + [X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff), + }; + + load_gdt(boot_gdt, X86_GDT_NUM_ENTRIES); + load_ds(X86_GDT_ENTRY_32BIT_DS); + load_es(X86_GDT_ENTRY_32BIT_DS); + load_fs(X86_GDT_ENTRY_32BIT_DS); + load_gs(X86_GDT_ENTRY_32BIT_DS); + load_ss(X86_GDT_ENTRY_32BIT_DS); /* Initialize core interrupt and exception functionality of CPU */ cpu_init_interrupts(); |