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#include <linux/io.h>
#include <linux/memblock.h>
#include <asm/cacheflush.h>
#include <asm/pgtable.h>
#include <asm/realmode.h>
struct real_mode_header *real_mode_header;
u32 *trampoline_cr4_features;
void __init setup_real_mode(void)
{
phys_addr_t mem;
u16 real_mode_seg;
u32 *rel;
u32 count;
u32 *ptr;
u16 *seg;
int i;
unsigned char *base;
struct trampoline_header *trampoline_header;
size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
#ifdef CONFIG_X86_64
u64 *trampoline_pgd;
u64 efer;
#endif
/* Has to be in very low memory so we can execute real-mode AP code. */
mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
if (!mem)
panic("Cannot allocate trampoline\n");
base = __va(mem);
memblock_reserve(mem, size);
real_mode_header = (struct real_mode_header *) base;
printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
base, (unsigned long long)mem, size);
memcpy(base, real_mode_blob, size);
real_mode_seg = __pa(base) >> 4;
rel = (u32 *) real_mode_relocs;
/* 16-bit segment relocations. */
count = rel[0];
rel = &rel[1];
for (i = 0; i < count; i++) {
seg = (u16 *) (base + rel[i]);
*seg = real_mode_seg;
}
/* 32-bit linear relocations. */
count = rel[i];
rel = &rel[i + 1];
for (i = 0; i < count; i++) {
ptr = (u32 *) (base + rel[i]);
*ptr += __pa(base);
}
/* Must be perfomed *after* relocation. */
trampoline_header = (struct trampoline_header *)
__va(real_mode_header->trampoline_header);
#ifdef CONFIG_X86_32
trampoline_header->start = __pa(startup_32_smp);
trampoline_header->gdt_limit = __BOOT_DS + 7;
trampoline_header->gdt_base = __pa(boot_gdt);
#else
/*
* Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
* so we need to mask it out.
*/
rdmsrl(MSR_EFER, efer);
trampoline_header->efer = efer & ~EFER_LMA;
trampoline_header->start = (u64) secondary_startup_64;
trampoline_cr4_features = &trampoline_header->cr4;
*trampoline_cr4_features = read_cr4();
trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
trampoline_pgd[511] = init_level4_pgt[511].pgd;
#endif
}
/*
* setup_real_mode() gets called very early, to guarantee the
* availability of low memory. This is before the proper kernel page
* tables are set up, so we cannot set page permissions in that
* function. Also trampoline code will be executed by APs so we
* need to mark it executable at do_pre_smp_initcalls() at least,
* thus run it as a early_initcall().
*/
static int __init set_real_mode_permissions(void)
{
unsigned char *base = (unsigned char *) real_mode_header;
size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
size_t ro_size =
PAGE_ALIGN(real_mode_header->ro_end) -
__pa(base);
size_t text_size =
PAGE_ALIGN(real_mode_header->ro_end) -
real_mode_header->text_start;
unsigned long text_start =
(unsigned long) __va(real_mode_header->text_start);
set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
return 0;
}
early_initcall(set_real_mode_permissions);
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