1 files changed, 74 insertions, 0 deletions

diff --git a/arch/x86/realmode/rm/trampoline_32.S b/arch/x86/realmode/rm/trampoline_32.S
new file mode 100644
index 000000000000..c1b2791183e7
--- /dev/null
+++ b/arch/x86/realmode/rm/trampoline_32.S
@@ -0,0 +1,74 @@
+/*
+ *
+ *      Trampoline.S    Derived from Setup.S by Linus Torvalds
+ *
+ *      4 Jan 1997 Michael Chastain: changed to gnu as.
+ *
+ *      This is only used for booting secondary CPUs in SMP machine
+ *
+ *      Entry: CS:IP point to the start of our code, we are
+ *      in real mode with no stack, but the rest of the
+ *      trampoline page to make our stack and everything else
+ *      is a mystery.
+ *
+ *      We jump into arch/x86/kernel/head_32.S.
+ *
+ *      On entry to trampoline_start, the processor is in real mode
+ *      with 16-bit addressing and 16-bit data.  CS has some value
+ *      and IP is zero.  Thus, we load CS to the physical segment
+ *      of the real mode code before doing anything further.
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/segment.h>
+#include <asm/page_types.h>
+#include "realmode.h"
+
+        .text
+        .code16
+
+        .balign PAGE_SIZE
+ENTRY(trampoline_start)
+        wbinvd                  # Needed for NUMA-Q should be harmless for others
+
+        LJMPW_RM(1f)
+1:
+        mov     %cs, %ax        # Code and data in the same place
+        mov     %ax, %ds
+
+        cli                     # We should be safe anyway
+
+        movl    tr_start, %eax  # where we need to go
+
+        movl    $0xA5A5A5A5, trampoline_status
+                                # write marker for master knows we're running
+
+        /*
+         * GDT tables in non default location kernel can be beyond 16MB and
+         * lgdt will not be able to load the address as in real mode default
+         * operand size is 16bit. Use lgdtl instead to force operand size
+         * to 32 bit.
+         */
+        lidtl   tr_idt                  # load idt with 0, 0
+        lgdtl   tr_gdt                  # load gdt with whatever is appropriate
+
+        movw    $1, %dx                 # protected mode (PE) bit
+        lmsw    %dx                     # into protected mode
+
+        ljmpl   $__BOOT_CS, $pa_startup_32
+
+        .section ".text32","ax"
+        .code32
+ENTRY(startup_32)                       # note: also used from wakeup_asm.S
+        jmp     *%eax
+
+        .bss
+        .balign 8
+GLOBAL(trampoline_header)
+        tr_start:               .space  4
+        tr_gdt_pad:             .space  2
+        tr_gdt:                 .space  6
+END(trampoline_header)
+        
+#include "trampoline_common.S"