2 #include <linux/memblock.h>
4 #include <asm/cacheflush.h>
5 #include <asm/pgtable.h>
6 #include <asm/realmode.h>
7 #include <asm/tlbflush.h>
9 struct real_mode_header *real_mode_header;
10 u32 *trampoline_cr4_features;
12 /* Hold the pgd entry used on booting additional CPUs */
13 pgd_t trampoline_pgd_entry;
15 void __init reserve_real_mode(void)
19 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
21 /* Has to be under 1M so we can execute real-mode AP code. */
22 mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
24 panic("Cannot allocate trampoline\n");
27 memblock_reserve(mem, size);
28 real_mode_header = (struct real_mode_header *) base;
29 printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
30 base, (unsigned long long)mem, size);
33 void __init setup_real_mode(void)
39 unsigned long phys_base;
40 struct trampoline_header *trampoline_header;
41 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
47 base = (unsigned char *)real_mode_header;
49 memcpy(base, real_mode_blob, size);
51 phys_base = __pa(base);
52 real_mode_seg = phys_base >> 4;
54 rel = (u32 *) real_mode_relocs;
56 /* 16-bit segment relocations. */
59 u16 *seg = (u16 *) (base + *rel++);
63 /* 32-bit linear relocations. */
66 u32 *ptr = (u32 *) (base + *rel++);
70 /* Must be perfomed *after* relocation. */
71 trampoline_header = (struct trampoline_header *)
72 __va(real_mode_header->trampoline_header);
75 trampoline_header->start = __pa_symbol(startup_32_smp);
76 trampoline_header->gdt_limit = __BOOT_DS + 7;
77 trampoline_header->gdt_base = __pa_symbol(boot_gdt);
80 * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
81 * so we need to mask it out.
83 rdmsrl(MSR_EFER, efer);
84 trampoline_header->efer = efer & ~EFER_LMA;
86 trampoline_header->start = (u64) secondary_startup_64;
87 trampoline_cr4_features = &trampoline_header->cr4;
88 *trampoline_cr4_features = mmu_cr4_features;
90 trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
91 trampoline_pgd[0] = trampoline_pgd_entry.pgd;
92 trampoline_pgd[511] = init_level4_pgt[511].pgd;
97 * reserve_real_mode() gets called very early, to guarantee the
98 * availability of low memory. This is before the proper kernel page
99 * tables are set up, so we cannot set page permissions in that
100 * function. Also trampoline code will be executed by APs so we
101 * need to mark it executable at do_pre_smp_initcalls() at least,
102 * thus run it as a early_initcall().
104 static int __init set_real_mode_permissions(void)
106 unsigned char *base = (unsigned char *) real_mode_header;
107 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
110 PAGE_ALIGN(real_mode_header->ro_end) -
114 PAGE_ALIGN(real_mode_header->ro_end) -
115 real_mode_header->text_start;
117 unsigned long text_start =
118 (unsigned long) __va(real_mode_header->text_start);
120 set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
121 set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
122 set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
126 early_initcall(set_real_mode_permissions);