x86, realmode: Move not-common bits out of trampoline_common.S

Move the bits that aren't actually common out of trampoline_common.S
and into the arch-specific files.  Furthermore, make sure the page
directory is first in the .bss section for trampoline_64.S in order to
not waste an entire page of memory.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
index 66e26f088288..1b9e1bc1ac5e 100644
--- a/arch/x86/realmode/rm/trampoline_64.S
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -125,4 +125,29 @@ ENTRY(startup_64)
         # Now jump into the kernel using virtual addresses
         jmpq    *tr_start(%rip)
 
+        .section ".rodata","a"
+        # Duplicate the global descriptor table
+        # so the kernel can live anywhere
+        .balign 16
+        .globl tr_gdt
+tr_gdt:
+        .short  tr_gdt_end - tr_gdt - 1 # gdt limit
+        .long   pa_tr_gdt
+        .short  0
+        .quad   0x00cf9b000000ffff      # __KERNEL32_CS
+        .quad   0x00af9b000000ffff      # __KERNEL_CS
+        .quad   0x00cf93000000ffff      # __KERNEL_DS
+tr_gdt_end:
+
+        .bss
+        .balign PAGE_SIZE
+GLOBAL(trampoline_pgd)          .space  PAGE_SIZE
+
+        .balign 8
+GLOBAL(trampoline_header)
+        tr_start:               .space  8
+        GLOBAL(tr_cr4)          .space  4
+        GLOBAL(tr_efer)         .space  8
+END(trampoline_header)
+
 #include "trampoline_common.S"