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: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 918a271..32f5a11 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -203,7 +203,7 @@
* 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
@@ -391,54 +391,16 @@
.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
ENTRY(idt_table)
diff --git a/arch/x86/kernel/setup64.c b/arch/x86/kernel/setup64.c
index fc1a56d..70ff071 100644
--- a/arch/x86/kernel/setup64.c
+++ b/arch/x86/kernel/setup64.c
@@ -202,11 +202,8 @@
* 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);
diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 504caea..a93300d 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -81,8 +81,6 @@
#define ARCH_SETUP
#endif
-#include "cpu/cpu.h"
-
/*
* Machine setup..
*/
@@ -228,6 +226,23 @@
}
#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
*
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index a71e3ca..fe2bd51 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -849,14 +849,8 @@
.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 @@
#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 @@
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 @@
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;
diff --git a/arch/x86/kernel/x8664_ksyms_64.c b/arch/x86/kernel/x8664_ksyms_64.c
index f6c05d0..2f306a8 100644
--- a/arch/x86/kernel/x8664_ksyms_64.c
+++ b/arch/x86/kernel/x8664_ksyms_64.c
@@ -53,8 +53,3 @@
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