linux/arch/x86/realmode/rm/trampoline_32.S
H. Peter Anvin 51edbe6a2f 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>
2012-05-16 13:44:10 -07:00

75 lines
1.8 KiB
ArmAsm

/*
*
* 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"