x86, realmode: Move kernel/realmode.c to realmode/init.c

Keep all the realmode code together, including initialization (only
the rm/ subdirectory is actually built as real-mode code, anyway.)

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>

2 files changed, 117 insertions, 0 deletions

diff --git a/arch/x86/realmode/Makefile b/arch/x86/realmode/Makefile
index a05b3aca64ad..94f7fbe97b08 100644
--- a/arch/x86/realmode/Makefile
+++ b/arch/x86/realmode/Makefile
@@ -9,6 +9,7 @@
 
 subdir- := rm
 
+obj-y += init.o
 obj-y += rmpiggy.o
 
 $(obj)/rmpiggy.o: $(obj)/rm/realmode.bin
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
new file mode 100644
index 000000000000..099277984b80
--- /dev/null
+++ b/arch/x86/realmode/init.c
@@ -0,0 +1,116 @@
+#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;
+        u32 efer_low, efer_high;
+#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.
+         */
+        rdmsr(MSR_EFER, efer_low, efer_high);
+        trampoline_header->efer_low  = efer_low & ~EFER_LMA;
+        trampoline_header->efer_high = efer_high;
+
+        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);