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 /* Hold the pgd entry used on booting additional CPUs */
12 pgd_t trampoline_pgd_entry;
14 void __init reserve_real_mode(void)
18 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
20 /* Has to be under 1M so we can execute real-mode AP code. */
21 mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
23 panic("Cannot allocate trampoline\n");
26 memblock_reserve(mem, size);
27 real_mode_header = (struct real_mode_header *) base;
28 printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
29 base, (unsigned long long)mem, size);
32 void __init setup_real_mode(void)
38 unsigned long phys_base;
39 struct trampoline_header *trampoline_header;
40 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
46 base = (unsigned char *)real_mode_header;
48 memcpy(base, real_mode_blob, size);
50 phys_base = __pa(base);
51 real_mode_seg = phys_base >> 4;
53 rel = (u32 *) real_mode_relocs;
55 /* 16-bit segment relocations. */
58 u16 *seg = (u16 *) (base + *rel++);
62 /* 32-bit linear relocations. */
65 u32 *ptr = (u32 *) (base + *rel++);
69 /* Must be perfomed *after* relocation. */
70 trampoline_header = (struct trampoline_header *)
71 __va(real_mode_header->trampoline_header);
74 trampoline_header->start = __pa_symbol(startup_32_smp);
75 trampoline_header->gdt_limit = __BOOT_DS + 7;
76 trampoline_header->gdt_base = __pa_symbol(boot_gdt);
79 * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
80 * so we need to mask it out.
82 rdmsrl(MSR_EFER, efer);
83 trampoline_header->efer = efer & ~EFER_LMA;
85 trampoline_header->start = (u64) secondary_startup_64;
86 trampoline_cr4_features = &trampoline_header->cr4;
87 *trampoline_cr4_features = __read_cr4();
89 trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
90 trampoline_pgd[0] = trampoline_pgd_entry.pgd;
91 trampoline_pgd[511] = init_level4_pgt[511].pgd;
96 * reserve_real_mode() gets called very early, to guarantee the
97 * availability of low memory. This is before the proper kernel page
98 * tables are set up, so we cannot set page permissions in that
99 * function. Also trampoline code will be executed by APs so we
100 * need to mark it executable at do_pre_smp_initcalls() at least,
101 * thus run it as a early_initcall().
103 static int __init set_real_mode_permissions(void)
105 unsigned char *base = (unsigned char *) real_mode_header;
106 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
109 PAGE_ALIGN(real_mode_header->ro_end) -
113 PAGE_ALIGN(real_mode_header->ro_end) -
114 real_mode_header->text_start;
116 unsigned long text_start =
117 (unsigned long) __va(real_mode_header->text_start);
119 set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
120 set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
121 set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
125 early_initcall(set_real_mode_permissions);