mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-21 11:44:01 +08:00
94a8a7acbe
Both trampolines actually *do* set up stack. (Is the "we jump into compressed/head.S" comment still true?) Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
81 lines
2.3 KiB
ArmAsm
81 lines
2.3 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_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 --reloc to make sure there are no relocation
|
|
* entries except for:
|
|
*
|
|
* TYPE VALUE
|
|
* R_386_32 startup_32_smp
|
|
* R_386_32 boot_gdt
|
|
*/
|
|
|
|
#include <linux/linkage.h>
|
|
#include <asm/segment.h>
|
|
#include <asm/page.h>
|
|
|
|
/* We can free up trampoline after bootup if cpu hotplug is not supported. */
|
|
#ifndef CONFIG_HOTPLUG_CPU
|
|
.section ".init.data","aw",@progbits
|
|
#else
|
|
.section .rodata,"a",@progbits
|
|
#endif
|
|
|
|
.code16
|
|
|
|
ENTRY(trampoline_data)
|
|
r_base = .
|
|
wbinvd # Needed for NUMA-Q should be harmless for others
|
|
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
|
|
|
|
/* 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 boot_idt_descr - r_base # load idt with 0, 0
|
|
lgdtl boot_gdt_descr - r_base # load gdt with whatever is appropriate
|
|
|
|
xor %ax, %ax
|
|
inc %ax # protected mode (PE) bit
|
|
lmsw %ax # into protected mode
|
|
# flush prefetch and jump to startup_32_smp in arch/i386/kernel/head.S
|
|
ljmpl $__BOOT_CS, $(startup_32_smp-__PAGE_OFFSET)
|
|
|
|
# These need to be in the same 64K segment as the above;
|
|
# hence we don't use the boot_gdt_descr defined in head.S
|
|
boot_gdt_descr:
|
|
.word __BOOT_DS + 7 # gdt limit
|
|
.long boot_gdt - __PAGE_OFFSET # gdt base
|
|
|
|
boot_idt_descr:
|
|
.word 0 # idt limit = 0
|
|
.long 0 # idt base = 0L
|
|
|
|
.globl trampoline_end
|
|
trampoline_end:
|