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
);