1 #include <linux/io.h> 2 #include <linux/memblock.h> 3 4 #include <asm/cacheflush.h> 5 #include <asm/pgtable.h> 6 #include <asm/realmode.h> 7 8 struct real_mode_header *real_mode_header; 9 u32 *trampoline_cr4_features; 10 11 void __init setup_real_mode(void) 12 { 13 phys_addr_t mem; 14 u16 real_mode_seg; 15 u32 *rel; 16 u32 count; 17 u32 *ptr; 18 u16 *seg; 19 int i; 20 unsigned char *base; 21 struct trampoline_header *trampoline_header; 22 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob); 23 #ifdef CONFIG_X86_64 24 u64 *trampoline_pgd; 25 u64 efer; 26 #endif 27 28 /* Has to be in very low memory so we can execute real-mode AP code. */ 29 mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE); 30 if (!mem) 31 panic("Cannot allocate trampoline\n"); 32 33 base = __va(mem); 34 memblock_reserve(mem, size); 35 real_mode_header = (struct real_mode_header *) base; 36 printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n", 37 base, (unsigned long long)mem, size); 38 39 memcpy(base, real_mode_blob, size); 40 41 real_mode_seg = __pa(base) >> 4; 42 rel = (u32 *) real_mode_relocs; 43 44 /* 16-bit segment relocations. */ 45 count = rel[0]; 46 rel = &rel[1]; 47 for (i = 0; i < count; i++) { 48 seg = (u16 *) (base + rel[i]); 49 *seg = real_mode_seg; 50 } 51 52 /* 32-bit linear relocations. */ 53 count = rel[i]; 54 rel = &rel[i + 1]; 55 for (i = 0; i < count; i++) { 56 ptr = (u32 *) (base + rel[i]); 57 *ptr += __pa(base); 58 } 59 60 /* Must be perfomed *after* relocation. */ 61 trampoline_header = (struct trampoline_header *) 62 __va(real_mode_header->trampoline_header); 63 64 #ifdef CONFIG_X86_32 65 trampoline_header->start = __pa(startup_32_smp); 66 trampoline_header->gdt_limit = __BOOT_DS + 7; 67 trampoline_header->gdt_base = __pa(boot_gdt); 68 #else 69 /* 70 * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR 71 * so we need to mask it out. 72 */ 73 rdmsrl(MSR_EFER, efer); 74 trampoline_header->efer = efer & ~EFER_LMA; 75 76 trampoline_header->start = (u64) secondary_startup_64; 77 trampoline_cr4_features = &trampoline_header->cr4; 78 *trampoline_cr4_features = read_cr4(); 79 80 trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd); 81 trampoline_pgd[0] = __pa(level3_ident_pgt) + _KERNPG_TABLE; 82 trampoline_pgd[511] = __pa(level3_kernel_pgt) + _KERNPG_TABLE; 83 #endif 84 } 85 86 /* 87 * set_real_mode_permissions() gets called very early, to guarantee the 88 * availability of low memory. This is before the proper kernel page 89 * tables are set up, so we cannot set page permissions in that 90 * function. Thus, we use an arch_initcall instead. 91 */ 92 static int __init set_real_mode_permissions(void) 93 { 94 unsigned char *base = (unsigned char *) real_mode_header; 95 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob); 96 97 size_t ro_size = 98 PAGE_ALIGN(real_mode_header->ro_end) - 99 __pa(base); 100 101 size_t text_size = 102 PAGE_ALIGN(real_mode_header->ro_end) - 103 real_mode_header->text_start; 104 105 unsigned long text_start = 106 (unsigned long) __va(real_mode_header->text_start); 107 108 set_memory_nx((unsigned long) base, size >> PAGE_SHIFT); 109 set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT); 110 set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT); 111 112 return 0; 113 } 114 115 arch_initcall(set_real_mode_permissions); 116