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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/x86_64/kernel/trampoline.S
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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diff --git a/arch/x86_64/kernel/trampoline.S b/arch/x86_64/kernel/trampoline.S
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+/*
+ *
+ * Trampoline.S Derived from Setup.S by Linus Torvalds
+ *
+ * 4 Jan 1997 Michael Chastain: changed to gnu as.
+ *
+ * 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.
+ *
+ * In fact we don't actually need a stack so we don't
+ * set one up.
+ *
+ * On entry to trampoline_data, the processor is in real mode
+ * with 16-bit addressing and 16-bit data. CS has some value
+ * and IP is zero. Thus, data addresses need to be absolute
+ * (no relocation) and are taken with regard to r_base.
+ *
+ * If you work on this file, check the object module with objdump
+ * --full-contents --reloc to make sure there are no relocation
+ * entries. For the GDT entry we do hand relocation in smpboot.c
+ * because of 64bit linker limitations.
+ */
+
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/page.h>
+
+.data
+
+.code16
+
+ENTRY(trampoline_data)
+r_base = .
+ wbinvd
+ mov %cs, %ax # Code and data in the same place
+ mov %ax, %ds
+
+ cli # We should be safe anyway
+
+ movl $0xA5A5A5A5, trampoline_data - r_base
+ # write marker for master knows we're running
+
+ lidt idt_48 - r_base # load idt with 0, 0
+ lgdt gdt_48 - r_base # load gdt with whatever is appropriate
+
+ xor %ax, %ax
+ inc %ax # protected mode (PE) bit
+ lmsw %ax # into protected mode
+ # flaush prefetch and jump to startup_32 in arch/x86_64/kernel/head.S
+ ljmpl $__KERNEL32_CS, $(startup_32-__START_KERNEL_map)
+
+ # Careful these need to be in the same 64K segment as the above;
+idt_48:
+ .word 0 # idt limit = 0
+ .word 0, 0 # idt base = 0L
+
+gdt_48:
+ .short __KERNEL32_CS + 7 # gdt limit
+ .long cpu_gdt_table-__START_KERNEL_map
+
+.globl trampoline_end
+trampoline_end: