diff options
Diffstat (limited to 'arch/x86/realmode/init.c')
| -rw-r--r-- | arch/x86/realmode/init.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c new file mode 100644 index 000000000000..cbca565af5bd --- /dev/null +++ b/arch/x86/realmode/init.c @@ -0,0 +1,115 @@ +#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] = __pa(level3_ident_pgt) + _KERNPG_TABLE; + trampoline_pgd[511] = __pa(level3_kernel_pgt) + _KERNPG_TABLE; +#endif +} + +/* + * set_real_mode_permissions() 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. Thus, we use an arch_initcall instead. + */ +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; +} + +arch_initcall(set_real_mode_permissions); |