2 #include <linux/memblock.h>
4 #include <asm/cacheflush.h>
5 #include <asm/pgtable.h>
6 #include <asm/realmode.h>
8 struct real_mode_header *real_mode_header;
9 u32 *trampoline_cr4_features;
11 void __init reserve_real_mode(void)
15 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
17 /* Has to be under 1M so we can execute real-mode AP code. */
18 mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
20 panic("Cannot allocate trampoline\n");
23 memblock_reserve(mem, size);
24 real_mode_header = (struct real_mode_header *) base;
25 printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
26 base, (unsigned long long)mem, size);
29 void __init setup_real_mode(void)
35 unsigned long phys_base;
36 struct trampoline_header *trampoline_header;
37 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
43 base = (unsigned char *)real_mode_header;
45 memcpy(base, real_mode_blob, size);
47 phys_base = __pa(base);
48 real_mode_seg = phys_base >> 4;
50 rel = (u32 *) real_mode_relocs;
52 /* 16-bit segment relocations. */
55 u16 *seg = (u16 *) (base + *rel++);
59 /* 32-bit linear relocations. */
62 u32 *ptr = (u32 *) (base + *rel++);
66 /* Must be perfomed *after* relocation. */
67 trampoline_header = (struct trampoline_header *)
68 __va(real_mode_header->trampoline_header);
71 trampoline_header->start = __pa_symbol(startup_32_smp);
72 trampoline_header->gdt_limit = __BOOT_DS + 7;
73 trampoline_header->gdt_base = __pa_symbol(boot_gdt);
76 * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
77 * so we need to mask it out.
79 rdmsrl(MSR_EFER, efer);
80 trampoline_header->efer = efer & ~EFER_LMA;
82 trampoline_header->start = (u64) secondary_startup_64;
83 trampoline_cr4_features = &trampoline_header->cr4;
84 *trampoline_cr4_features = __read_cr4();
86 trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
87 trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
88 trampoline_pgd[511] = init_level4_pgt[511].pgd;
93 * reserve_real_mode() gets called very early, to guarantee the
94 * availability of low memory. This is before the proper kernel page
95 * tables are set up, so we cannot set page permissions in that
96 * function. Also trampoline code will be executed by APs so we
97 * need to mark it executable at do_pre_smp_initcalls() at least,
98 * thus run it as a early_initcall().
100 static int __init set_real_mode_permissions(void)
102 unsigned char *base = (unsigned char *) real_mode_header;
103 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
106 PAGE_ALIGN(real_mode_header->ro_end) -
110 PAGE_ALIGN(real_mode_header->ro_end) -
111 real_mode_header->text_start;
113 unsigned long text_start =
114 (unsigned long) __va(real_mode_header->text_start);
116 set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
117 set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
118 set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
122 early_initcall(set_real_mode_permissions);