Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a939098a authored by Glauber Costa's avatar Glauber Costa Committed by Ingo Molnar
Browse files

x86: move x86_64 gdt closer to i386 



i386 and x86_64 used two different schemes for maintaining the gdt.
With this patch, x86_64 initial gdt table is defined in a .c file,
same way as i386 is now. Also, we call it "gdt_page", and the descriptor,
"early_gdt_descr". This way we achieve common naming, which can allow for
more code integration.

Signed-off-by: default avatarGlauber Costa <gcosta@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 736f12bf

arch/x86/kernel/head_64.S

+5 −43
Original line number Diff line number Diff line
@@ -203,7 +203,7 @@ ENTRY(secondary_startup_64) 
	 * addresses where we're currently running on. We have to do that here

	 * because in 32bit we couldn't load a 64bit linear address.

	 */

	lgdt	cpu_gdt_descr(%rip)

	lgdt	early_gdt_descr(%rip)



	/* set up data segments. actually 0 would do too */

	movl $__KERNEL_DS,%eax
@@ -391,53 +391,15 @@ NEXT_PAGE(level2_spare_pgt) 


	.data

	.align 16

	.globl cpu_gdt_descr

cpu_gdt_descr:

	.word	gdt_end-cpu_gdt_table-1

gdt:

	.quad	cpu_gdt_table

#ifdef CONFIG_SMP

	.rept	NR_CPUS-1

	.word	0

	.quad	0

	.endr

#endif

	.globl early_gdt_descr

early_gdt_descr:

	.word	GDT_ENTRIES*8-1

	.quad   per_cpu__gdt_page



ENTRY(phys_base)

	/* This must match the first entry in level2_kernel_pgt */

	.quad   0x0000000000000000



/* We need valid kernel segments for data and code in long mode too

 * IRET will check the segment types  kkeil 2000/10/28

 * Also sysret mandates a special GDT layout 

 */

		 		

	.section .data.page_aligned, "aw"

	.align PAGE_SIZE



/* The TLS descriptors are currently at a different place compared to i386.

   Hopefully nobody expects them at a fixed place (Wine?) */

	

ENTRY(cpu_gdt_table)

	.quad	0x0000000000000000	/* NULL descriptor */

	.quad	0x00cf9b000000ffff	/* __KERNEL32_CS */

	.quad	0x00af9b000000ffff	/* __KERNEL_CS */

	.quad	0x00cf93000000ffff	/* __KERNEL_DS */

	.quad	0x00cffb000000ffff	/* __USER32_CS */

	.quad	0x00cff3000000ffff	/* __USER_DS, __USER32_DS  */

	.quad	0x00affb000000ffff	/* __USER_CS */

	.quad	0x0			/* unused */

	.quad	0,0			/* TSS */

	.quad	0,0			/* LDT */

	.quad   0,0,0			/* three TLS descriptors */ 

	.quad	0x0000f40000000000	/* node/CPU stored in limit */

gdt_end:	

	/* asm/segment.h:GDT_ENTRIES must match this */	

	/* This should be a multiple of the cache line size */

	/* GDTs of other CPUs are now dynamically allocated */



	/* zero the remaining page */

	.fill PAGE_SIZE / 8 - GDT_ENTRIES,8,0

	

	.section .bss, "aw", @nobits

	.align L1_CACHE_BYTES

arch/x86/kernel/setup64.c

+1 −4
Original line number Diff line number Diff line
@@ -202,11 +202,8 @@ void __cpuinit cpu_init (void) 
	 * Initialize the per-CPU GDT with the boot GDT,

	 * and set up the GDT descriptor:

	 */

	if (cpu)

		memcpy(get_cpu_gdt_table(cpu), cpu_gdt_table, GDT_SIZE);



	cpu_gdt_descr[cpu].size = GDT_SIZE;

	load_gdt((const struct desc_ptr *)&cpu_gdt_descr[cpu]);

	switch_to_new_gdt();

	load_idt((const struct desc_ptr *)&idt_descr);



	memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);

arch/x86/kernel/setup_64.c

+17 −2
Original line number Diff line number Diff line
@@ -81,8 +81,6 @@ 
#define ARCH_SETUP

#endif



#include "cpu/cpu.h"



/*

 * Machine setup..

 */
@@ -228,6 +226,23 @@ static inline void copy_edd(void) 
}

#endif



/* Overridden in paravirt.c if CONFIG_PARAVIRT */

void __attribute__((weak)) __init memory_setup(void)

{

       machine_specific_memory_setup();

}



/* Current gdt points %fs at the "master" per-cpu area: after this,

 * it's on the real one. */

void switch_to_new_gdt(void)

{

	struct desc_ptr gdt_descr;



	gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());

	gdt_descr.size = GDT_SIZE - 1;

	load_gdt(&gdt_descr);

}



/*

 * setup_arch - architecture-specific boot-time initializations

 *

arch/x86/kernel/smpboot.c

+3 −9
Original line number Diff line number Diff line
@@ -849,14 +849,8 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
		.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),

	};

	INIT_WORK(&c_idle.work, do_fork_idle);

#ifdef CONFIG_X86_64

	/* allocate memory for gdts of secondary cpus. Hotplug is considered */

	if (!cpu_gdt_descr[cpu].address &&

		!(cpu_gdt_descr[cpu].address = get_zeroed_page(GFP_KERNEL))) {

		printk(KERN_ERR "Failed to allocate GDT for CPU %d\n", cpu);

		return -1;

	}



#ifdef CONFIG_X86_64

	/* Allocate node local memory for AP pdas */

	if (cpu > 0) {

		boot_error = get_local_pda(cpu);
@@ -898,7 +892,6 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
#ifdef CONFIG_X86_32

	per_cpu(current_task, cpu) = c_idle.idle;

	init_gdt(cpu);

	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);

	c_idle.idle->thread.ip = (unsigned long) start_secondary;

	/* Stack for startup_32 can be just as for start_secondary onwards */

	irq_ctx_init(cpu);
@@ -908,6 +901,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) 
	initial_code = (unsigned long)start_secondary;

	clear_tsk_thread_flag(c_idle.idle, TIF_FORK);

#endif

	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);

	stack_start.sp = (void *) c_idle.idle->thread.sp;



	/* start_ip had better be page-aligned! */
@@ -1252,8 +1246,8 @@ void __init native_smp_prepare_boot_cpu(void) 
	int me = smp_processor_id();

#ifdef CONFIG_X86_32

	init_gdt(me);

	switch_to_new_gdt();

#endif

	switch_to_new_gdt();

	/* already set me in cpu_online_map in boot_cpu_init() */

	cpu_set(me, cpu_callout_map);

	per_cpu(cpu_state, me) = CPU_ONLINE;

arch/x86/kernel/x8664_ksyms_64.c

+0 −5
Original line number Diff line number Diff line
@@ -53,8 +53,3 @@ EXPORT_SYMBOL(init_level4_pgt); 
EXPORT_SYMBOL(load_gs_index);



EXPORT_SYMBOL(_proxy_pda);
 


#ifdef CONFIG_PARAVIRT

/* Virtualized guests may want to use it */

EXPORT_SYMBOL_GPL(cpu_gdt_descr);

#endif