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authorSrikant Patnaik2015-01-11 12:28:04 +0530
committerSrikant Patnaik2015-01-11 12:28:04 +0530
commit871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch)
tree8718f573808810c2a1e8cb8fb6ac469093ca2784 /arch/x86/kernel/trampoline_64.S
parent9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff)
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized. Changes are basically to make it look like kernel structure.
Diffstat (limited to 'arch/x86/kernel/trampoline_64.S')
-rw-r--r--arch/x86/kernel/trampoline_64.S171
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/x86/kernel/trampoline_64.S b/arch/x86/kernel/trampoline_64.S
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+/*
+ *
+ * Trampoline.S Derived from Setup.S by Linus Torvalds
+ *
+ * 4 Jan 1997 Michael Chastain: changed to gnu as.
+ * 15 Sept 2005 Eric Biederman: 64bit PIC support
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * With the addition of trampoline_level4_pgt this code can
+ * now enter a 64bit kernel that lives at arbitrary 64bit
+ * physical addresses.
+ *
+ * If you work on this file, check the object module with objdump
+ * --full-contents --reloc to make sure there are no relocation
+ * entries.
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/pgtable_types.h>
+#include <asm/page_types.h>
+#include <asm/msr.h>
+#include <asm/segment.h>
+#include <asm/processor-flags.h>
+
+ .section ".x86_trampoline","a"
+ .balign PAGE_SIZE
+ .code16
+
+ENTRY(trampoline_data)
+r_base = .
+ cli # We should be safe anyway
+ wbinvd
+ mov %cs, %ax # Code and data in the same place
+ mov %ax, %ds
+ mov %ax, %es
+ mov %ax, %ss
+
+
+ movl $0xA5A5A5A5, trampoline_status - r_base
+ # write marker for master knows we're running
+
+ # Setup stack
+ movw $(trampoline_stack_end - r_base), %sp
+
+ call verify_cpu # Verify the cpu supports long mode
+ testl %eax, %eax # Check for return code
+ jnz no_longmode
+
+ mov %cs, %ax
+ movzx %ax, %esi # Find the 32bit trampoline location
+ shll $4, %esi
+
+ # Fixup the absolute vectors
+ leal (startup_32 - r_base)(%esi), %eax
+ movl %eax, startup_32_vector - r_base
+ leal (startup_64 - r_base)(%esi), %eax
+ movl %eax, startup_64_vector - r_base
+ leal (tgdt - r_base)(%esi), %eax
+ movl %eax, (tgdt + 2 - r_base)
+
+ /*
+ * 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 tidt - r_base # load idt with 0, 0
+ lgdtl tgdt - r_base # load gdt with whatever is appropriate
+
+ mov $X86_CR0_PE, %ax # protected mode (PE) bit
+ lmsw %ax # into protected mode
+
+ # flush prefetch and jump to startup_32
+ ljmpl *(startup_32_vector - r_base)
+
+ .code32
+ .balign 4
+startup_32:
+ movl $__KERNEL_DS, %eax # Initialize the %ds segment register
+ movl %eax, %ds
+
+ movl $X86_CR4_PAE, %eax
+ movl %eax, %cr4 # Enable PAE mode
+
+ # Setup trampoline 4 level pagetables
+ leal (trampoline_level4_pgt - r_base)(%esi), %eax
+ movl %eax, %cr3
+
+ movl $MSR_EFER, %ecx
+ movl $(1 << _EFER_LME), %eax # Enable Long Mode
+ xorl %edx, %edx
+ wrmsr
+
+ # Enable paging and in turn activate Long Mode
+ # Enable protected mode
+ movl $(X86_CR0_PG | X86_CR0_PE), %eax
+ movl %eax, %cr0
+
+ /*
+ * At this point we're in long mode but in 32bit compatibility mode
+ * with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
+ * EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
+ * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
+ */
+ ljmp *(startup_64_vector - r_base)(%esi)
+
+ .code64
+ .balign 4
+startup_64:
+ # Now jump into the kernel using virtual addresses
+ movq $secondary_startup_64, %rax
+ jmp *%rax
+
+ .code16
+no_longmode:
+ hlt
+ jmp no_longmode
+#include "verify_cpu.S"
+
+ .balign 4
+ # Careful these need to be in the same 64K segment as the above;
+tidt:
+ .word 0 # idt limit = 0
+ .word 0, 0 # idt base = 0L
+
+ # Duplicate the global descriptor table
+ # so the kernel can live anywhere
+ .balign 4
+tgdt:
+ .short tgdt_end - tgdt # gdt limit
+ .long tgdt - r_base
+ .short 0
+ .quad 0x00cf9b000000ffff # __KERNEL32_CS
+ .quad 0x00af9b000000ffff # __KERNEL_CS
+ .quad 0x00cf93000000ffff # __KERNEL_DS
+tgdt_end:
+
+ .balign 4
+startup_32_vector:
+ .long startup_32 - r_base
+ .word __KERNEL32_CS, 0
+
+ .balign 4
+startup_64_vector:
+ .long startup_64 - r_base
+ .word __KERNEL_CS, 0
+
+ .balign 4
+ENTRY(trampoline_status)
+ .long 0
+
+trampoline_stack:
+ .org 0x1000
+trampoline_stack_end:
+ENTRY(trampoline_level4_pgt)
+ .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+ .fill 510,8,0
+ .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
+
+ENTRY(trampoline_end)