From a939098afcfa5f81d3474782ec15c6d114e57763 Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Wed, 28 May 2008 16:19:53 -0700 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar --- arch/x86/kernel/head_64.S | 48 ++++---------------------------- arch/x86/kernel/setup64.c | 5 +--- arch/x86/kernel/setup_64.c | 19 +++++++++++-- arch/x86/kernel/smpboot.c | 12 ++------ arch/x86/kernel/x8664_ksyms_64.c | 5 ---- include/asm-x86/desc.h | 24 +++++++--------- include/asm-x86/segment.h | 23 +++++++-------- 7 files changed, 48 insertions(+), 88 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 918a2711aff..32f5a114d1a 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -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 @@ -391,54 +391,16 @@ 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 ENTRY(idt_table) diff --git a/arch/x86/kernel/setup64.c b/arch/x86/kernel/setup64.c index fc1a56da824..70ff0718677 100644 --- a/arch/x86/kernel/setup64.c +++ b/arch/x86/kernel/setup64.c @@ -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); diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c index 504caeaffd5..a93300de4da 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 @@ 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 * diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index a71e3cad547..fe2bd515d6c 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -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 @@ do_rest: #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 @@ do_rest: 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; diff --git a/arch/x86/kernel/x8664_ksyms_64.c b/arch/x86/kernel/x8664_ksyms_64.c index f6c05d0410f..2f306a82689 100644 --- a/arch/x86/kernel/x8664_ksyms_64.c +++ b/arch/x86/kernel/x8664_ksyms_64.c @@ -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 diff --git a/include/asm-x86/desc.h b/include/asm-x86/desc.h index b3875d4b4fa..07f9f2b17be 100644 --- a/include/asm-x86/desc.h +++ b/include/asm-x86/desc.h @@ -29,11 +29,17 @@ static inline void fill_ldt(struct desc_struct *desc, extern struct desc_ptr idt_descr; extern gate_desc idt_table[]; +struct gdt_page { + struct desc_struct gdt[GDT_ENTRIES]; +} __attribute__((aligned(PAGE_SIZE))); +DECLARE_PER_CPU(struct gdt_page, gdt_page); + +static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu) +{ + return per_cpu(gdt_page, cpu).gdt; +} + #ifdef CONFIG_X86_64 -extern struct desc_struct cpu_gdt_table[GDT_ENTRIES]; -extern struct desc_ptr cpu_gdt_descr[]; -/* the cpu gdt accessor */ -#define get_cpu_gdt_table(x) ((struct desc_struct *)cpu_gdt_descr[x].address) static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func, unsigned dpl, unsigned ist, unsigned seg) @@ -51,16 +57,6 @@ static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func, } #else -struct gdt_page { - struct desc_struct gdt[GDT_ENTRIES]; -} __attribute__((aligned(PAGE_SIZE))); -DECLARE_PER_CPU(struct gdt_page, gdt_page); - -static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu) -{ - return per_cpu(gdt_page, cpu).gdt; -} - static inline void pack_gate(gate_desc *gate, unsigned char type, unsigned long base, unsigned dpl, unsigned flags, unsigned short seg) diff --git a/include/asm-x86/segment.h b/include/asm-x86/segment.h index ed5131dd7d9..dfc8601c089 100644 --- a/include/asm-x86/segment.h +++ b/include/asm-x86/segment.h @@ -61,18 +61,14 @@ #define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1) #define GDT_ENTRY_DEFAULT_USER_CS 14 -#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS * 8 + 3) #define GDT_ENTRY_DEFAULT_USER_DS 15 -#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS * 8 + 3) #define GDT_ENTRY_KERNEL_BASE 12 #define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE + 0) -#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8) #define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE + 1) -#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8) #define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE + 4) #define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE + 5) @@ -139,10 +135,11 @@ #else #include -#define __KERNEL_CS 0x10 -#define __KERNEL_DS 0x18 +#define GDT_ENTRY_KERNEL32_CS 1 +#define GDT_ENTRY_KERNEL_CS 2 +#define GDT_ENTRY_KERNEL_DS 3 -#define __KERNEL32_CS 0x08 +#define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS * 8) /* * we cannot use the same code segment descriptor for user and kernel @@ -150,10 +147,10 @@ * The segment offset needs to contain a RPL. Grr. -AK * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets) */ - -#define __USER32_CS 0x23 /* 4*8+3 */ -#define __USER_DS 0x2b /* 5*8+3 */ -#define __USER_CS 0x33 /* 6*8+3 */ +#define GDT_ENTRY_DEFAULT_USER32_CS 4 +#define GDT_ENTRY_DEFAULT_USER_DS 5 +#define GDT_ENTRY_DEFAULT_USER_CS 6 +#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS * 8 + 3) #define __USER32_DS __USER_DS #define GDT_ENTRY_TSS 8 /* needs two entries */ @@ -175,6 +172,10 @@ #endif +#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8) +#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8) +#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS* 8 + 3) +#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS* 8 + 3) #ifndef CONFIG_PARAVIRT #define get_kernel_rpl() 0 #endif -- 2.41.1