From ae1ee11be77f51cedb6c569887dddc70c163ab6d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 2 May 2007 19:27:10 +0200 Subject: [PATCH] i386: Use per-cpu variables for GDT, PDA Allocating PDA and GDT at boot is a pain. Using simple per-cpu variables adds happiness (although we need the GDT page-aligned for Xen, which we do in a followup patch). [akpm@linux-foundation.org: build fix] Signed-off-by: Rusty Russell Signed-off-by: Andi Kleen Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/kernel/cpu/common.c | 94 ++++++------------------------------------- 1 file changed, 13 insertions(+), 81 deletions(-) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index dcbbd0a8bfc2..2335f4464ead 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -25,8 +25,10 @@ DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr); EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr); -struct i386_pda *_cpu_pda[NR_CPUS] __read_mostly; -EXPORT_SYMBOL(_cpu_pda); +DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]); + +DEFINE_PER_CPU(struct i386_pda, _cpu_pda); +EXPORT_PER_CPU_SYMBOL(_cpu_pda); static int cachesize_override __cpuinitdata = -1; static int disable_x86_fxsr __cpuinitdata; @@ -609,52 +611,6 @@ struct pt_regs * __devinit idle_regs(struct pt_regs *regs) return regs; } -static __cpuinit int alloc_gdt(int cpu) -{ - struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); - struct desc_struct *gdt; - struct i386_pda *pda; - - gdt = (struct desc_struct *)cpu_gdt_descr->address; - pda = cpu_pda(cpu); - - /* - * This is a horrible hack to allocate the GDT. The problem - * is that cpu_init() is called really early for the boot CPU - * (and hence needs bootmem) but much later for the secondary - * CPUs, when bootmem will have gone away - */ - if (NODE_DATA(0)->bdata->node_bootmem_map) { - BUG_ON(gdt != NULL || pda != NULL); - - gdt = alloc_bootmem_pages(PAGE_SIZE); - pda = alloc_bootmem(sizeof(*pda)); - /* alloc_bootmem(_pages) panics on failure, so no check */ - - memset(gdt, 0, PAGE_SIZE); - memset(pda, 0, sizeof(*pda)); - } else { - /* GDT and PDA might already have been allocated if - this is a CPU hotplug re-insertion. */ - if (gdt == NULL) - gdt = (struct desc_struct *)get_zeroed_page(GFP_KERNEL); - - if (pda == NULL) - pda = kmalloc_node(sizeof(*pda), GFP_KERNEL, cpu_to_node(cpu)); - - if (unlikely(!gdt || !pda)) { - free_pages((unsigned long)gdt, 0); - kfree(pda); - return 0; - } - } - - cpu_gdt_descr->address = (unsigned long)gdt; - cpu_pda(cpu) = pda; - - return 1; -} - /* Initial PDA used by boot CPU */ struct i386_pda boot_pda = { ._pda = &boot_pda, @@ -670,31 +626,17 @@ static inline void set_kernel_fs(void) asm volatile ("mov %0, %%fs" : : "r" (__KERNEL_PDA) : "memory"); } -/* Initialize the CPU's GDT and PDA. The boot CPU does this for - itself, but secondaries find this done for them. */ -__cpuinit int init_gdt(int cpu, struct task_struct *idle) +/* Initialize the CPU's GDT and PDA. This is either the boot CPU doing itself + (still using cpu_gdt_table), or a CPU doing it for a secondary which + will soon come up. */ +__cpuinit void init_gdt(int cpu, struct task_struct *idle) { struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); - struct desc_struct *gdt; - struct i386_pda *pda; - - /* For non-boot CPUs, the GDT and PDA should already have been - allocated. */ - if (!alloc_gdt(cpu)) { - printk(KERN_CRIT "CPU%d failed to allocate GDT or PDA\n", cpu); - return 0; - } + struct desc_struct *gdt = per_cpu(cpu_gdt, cpu); + struct i386_pda *pda = &per_cpu(_cpu_pda, cpu); - gdt = (struct desc_struct *)cpu_gdt_descr->address; - pda = cpu_pda(cpu); - - BUG_ON(gdt == NULL || pda == NULL); - - /* - * Initialize the per-CPU GDT with the boot GDT, - * and set up the GDT descriptor: - */ memcpy(gdt, cpu_gdt_table, GDT_SIZE); + cpu_gdt_descr->address = (unsigned long)gdt; cpu_gdt_descr->size = GDT_SIZE - 1; pack_descriptor((u32 *)&gdt[GDT_ENTRY_PDA].a, @@ -706,17 +648,12 @@ __cpuinit int init_gdt(int cpu, struct task_struct *idle) pda->_pda = pda; pda->cpu_number = cpu; pda->pcurrent = idle; - - return 1; } void __cpuinit cpu_set_gdt(int cpu) { struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); - /* Reinit these anyway, even if they've already been done (on - the boot CPU, this will transition from the boot gdt+pda to - the real ones). */ load_gdt(cpu_gdt_descr); set_kernel_fs(); } @@ -804,13 +741,8 @@ void __cpuinit cpu_init(void) struct task_struct *curr = current; /* Set up the real GDT and PDA, so we can transition from the - boot versions. */ - if (!init_gdt(cpu, curr)) { - /* failed to allocate something; not much we can do... */ - for (;;) - local_irq_enable(); - } - + boot_gdt_table & boot_pda. */ + init_gdt(cpu, curr); cpu_set_gdt(cpu); _cpu_init(cpu, curr); } -- cgit v1.2.3 From bf50467204b435421d8de33ad080fa46c6f3d50b Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 2 May 2007 19:27:10 +0200 Subject: [PATCH] i386: Use per-cpu GDT immediately upon boot Now we are no longer dynamically allocating the GDT, we don't need the "cpu_gdt_table" at all: we can switch straight from "boot_gdt_table" to the per-cpu GDT. This means initializing the cpu_gdt array in C. The boot CPU uses the per-cpu var directly, then in smp_prepare_cpus() it switches to the per-cpu copy just allocated. For secondary CPUs, the early_gdt_descr is set to point directly to their per-cpu copy. For UP the code is very simple: it keeps using the "per-cpu" GDT as per SMP, but we never have to move. Signed-off-by: Rusty Russell Signed-off-by: Andi Kleen Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/kernel/cpu/common.c | 72 ++++++++++++++++--------------------------- 1 file changed, 27 insertions(+), 45 deletions(-) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 2335f4464ead..fd6b079f7609 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -25,7 +25,33 @@ DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr); EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr); -DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]); +DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = { + [GDT_ENTRY_KERNEL_CS] = { 0x0000ffff, 0x00cf9a00 }, + [GDT_ENTRY_KERNEL_DS] = { 0x0000ffff, 0x00cf9200 }, + [GDT_ENTRY_DEFAULT_USER_CS] = { 0x0000ffff, 0x00cffa00 }, + [GDT_ENTRY_DEFAULT_USER_DS] = { 0x0000ffff, 0x00cff200 }, + /* + * Segments used for calling PnP BIOS have byte granularity. + * They code segments and data segments have fixed 64k limits, + * the transfer segment sizes are set at run time. + */ + [GDT_ENTRY_PNPBIOS_CS32] = { 0x0000ffff, 0x00409a00 },/* 32-bit code */ + [GDT_ENTRY_PNPBIOS_CS16] = { 0x0000ffff, 0x00009a00 },/* 16-bit code */ + [GDT_ENTRY_PNPBIOS_DS] = { 0x0000ffff, 0x00009200 }, /* 16-bit data */ + [GDT_ENTRY_PNPBIOS_TS1] = { 0x00000000, 0x00009200 },/* 16-bit data */ + [GDT_ENTRY_PNPBIOS_TS2] = { 0x00000000, 0x00009200 },/* 16-bit data */ + /* + * The APM segments have byte granularity and their bases + * are set at run time. All have 64k limits. + */ + [GDT_ENTRY_APMBIOS_BASE] = { 0x0000ffff, 0x00409a00 },/* 32-bit code */ + /* 16-bit code */ + [GDT_ENTRY_APMBIOS_BASE+1] = { 0x0000ffff, 0x00009a00 }, + [GDT_ENTRY_APMBIOS_BASE+2] = { 0x0000ffff, 0x00409200 }, /* data */ + + [GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 }, + [GDT_ENTRY_PDA] = { 0x00000000, 0x00c09200 }, /* set in setup_pda */ +}; DEFINE_PER_CPU(struct i386_pda, _cpu_pda); EXPORT_PER_CPU_SYMBOL(_cpu_pda); @@ -618,46 +644,6 @@ struct i386_pda boot_pda = { .pcurrent = &init_task, }; -static inline void set_kernel_fs(void) -{ - /* Set %fs for this CPU's PDA. Memory clobber is to create a - barrier with respect to any PDA operations, so the compiler - doesn't move any before here. */ - asm volatile ("mov %0, %%fs" : : "r" (__KERNEL_PDA) : "memory"); -} - -/* Initialize the CPU's GDT and PDA. This is either the boot CPU doing itself - (still using cpu_gdt_table), or a CPU doing it for a secondary which - will soon come up. */ -__cpuinit void init_gdt(int cpu, struct task_struct *idle) -{ - struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); - struct desc_struct *gdt = per_cpu(cpu_gdt, cpu); - struct i386_pda *pda = &per_cpu(_cpu_pda, cpu); - - memcpy(gdt, cpu_gdt_table, GDT_SIZE); - cpu_gdt_descr->address = (unsigned long)gdt; - cpu_gdt_descr->size = GDT_SIZE - 1; - - pack_descriptor((u32 *)&gdt[GDT_ENTRY_PDA].a, - (u32 *)&gdt[GDT_ENTRY_PDA].b, - (unsigned long)pda, sizeof(*pda) - 1, - 0x80 | DESCTYPE_S | 0x2, 0); /* present read-write data segment */ - - memset(pda, 0, sizeof(*pda)); - pda->_pda = pda; - pda->cpu_number = cpu; - pda->pcurrent = idle; -} - -void __cpuinit cpu_set_gdt(int cpu) -{ - struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); - - load_gdt(cpu_gdt_descr); - set_kernel_fs(); -} - /* Common CPU init for both boot and secondary CPUs */ static void __cpuinit _cpu_init(int cpu, struct task_struct *curr) { @@ -740,10 +726,6 @@ void __cpuinit cpu_init(void) int cpu = smp_processor_id(); struct task_struct *curr = current; - /* Set up the real GDT and PDA, so we can transition from the - boot_gdt_table & boot_pda. */ - init_gdt(cpu, curr); - cpu_set_gdt(cpu); _cpu_init(cpu, curr); } -- cgit v1.2.3 From d2cbcc49e2bfd6eaa44d7e4e5e5f171aaa5ec80d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 2 May 2007 19:27:10 +0200 Subject: [PATCH] i386: clean up cpu_init() We now have cpu_init() and secondary_cpu_init() doing nothing but calling _cpu_init() with the same arguments. Rename _cpu_init() to cpu_init() and use it as a replcement for secondary_cpu_init(). Signed-off-by: Rusty Russell Signed-off-by: Andi Kleen Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/kernel/cpu/common.c | 34 +++++++++------------------------- 1 file changed, 9 insertions(+), 25 deletions(-) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index fd6b079f7609..2a26956fce42 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -644,9 +644,16 @@ struct i386_pda boot_pda = { .pcurrent = &init_task, }; -/* Common CPU init for both boot and secondary CPUs */ -static void __cpuinit _cpu_init(int cpu, struct task_struct *curr) +/* + * cpu_init() initializes state that is per-CPU. Some data is already + * initialized (naturally) in the bootstrap process, such as the GDT + * and IDT. We reload them nevertheless, this function acts as a + * 'CPU state barrier', nothing should get across. + */ +void __cpuinit cpu_init(void) { + int cpu = smp_processor_id(); + struct task_struct *curr = current; struct tss_struct * t = &per_cpu(init_tss, cpu); struct thread_struct *thread = &curr->thread; @@ -706,29 +713,6 @@ static void __cpuinit _cpu_init(int cpu, struct task_struct *curr) mxcsr_feature_mask_init(); } -/* Entrypoint to initialize secondary CPU */ -void __cpuinit secondary_cpu_init(void) -{ - int cpu = smp_processor_id(); - struct task_struct *curr = current; - - _cpu_init(cpu, curr); -} - -/* - * cpu_init() initializes state that is per-CPU. Some data is already - * initialized (naturally) in the bootstrap process, such as the GDT - * and IDT. We reload them nevertheless, this function acts as a - * 'CPU state barrier', nothing should get across. - */ -void __cpuinit cpu_init(void) -{ - int cpu = smp_processor_id(); - struct task_struct *curr = current; - - _cpu_init(cpu, curr); -} - #ifdef CONFIG_HOTPLUG_CPU void __cpuinit cpu_uninit(void) { -- cgit v1.2.3 From 4fbb5968810b237e81977f131986b9efd5245368 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 2 May 2007 19:27:11 +0200 Subject: [PATCH] i386: cleanup GDT Access Now we have an explicit per-cpu GDT variable, we don't need to keep the descriptors around to use them to find the GDT: expose cpu_gdt directly. We could go further and make load_gdt() pack the descriptor for us, or even assume it means "load the current cpu's GDT" which is what it always does. Signed-off-by: Rusty Russell Signed-off-by: Andi Kleen Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/kernel/cpu/common.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 2a26956fce42..5faf675aab4b 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -22,9 +22,6 @@ #include "cpu.h" -DEFINE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr); -EXPORT_PER_CPU_SYMBOL(cpu_gdt_descr); - DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = { [GDT_ENTRY_KERNEL_CS] = { 0x0000ffff, 0x00cf9a00 }, [GDT_ENTRY_KERNEL_DS] = { 0x0000ffff, 0x00cf9200 }, @@ -52,6 +49,7 @@ DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = { [GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 }, [GDT_ENTRY_PDA] = { 0x00000000, 0x00c09200 }, /* set in setup_pda */ }; +EXPORT_PER_CPU_SYMBOL_GPL(cpu_gdt); DEFINE_PER_CPU(struct i386_pda, _cpu_pda); EXPORT_PER_CPU_SYMBOL(_cpu_pda); -- cgit v1.2.3 From a6c4e076ee4c1ea670e4faa55814e63dd08e3f29 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 2 May 2007 19:27:12 +0200 Subject: [PATCH] i386: clean up identify_cpu identify_cpu() is used to identify both the boot CPU and secondary CPUs, but it performs some actions which only apply to the boot CPU. Those functions are therefore really __init functions, but because they're called by identify_cpu(), they must be marked __cpuinit. This patch splits identify_cpu() into identify_boot_cpu() and identify_secondary_cpu(), and calls the appropriate init functions from each. Also, identify_boot_cpu() and all the functions it dominates are marked __init. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen --- arch/i386/kernel/cpu/common.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 5faf675aab4b..58128585ae60 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -394,7 +394,7 @@ __setup("serialnumber", x86_serial_nr_setup); /* * This does the hard work of actually picking apart the CPU stuff... */ -void __cpuinit identify_cpu(struct cpuinfo_x86 *c) +static void __cpuinit identify_cpu(struct cpuinfo_x86 *c) { int i; @@ -505,15 +505,22 @@ void __cpuinit identify_cpu(struct cpuinfo_x86 *c) /* Init Machine Check Exception if available. */ mcheck_init(c); +} - if (c == &boot_cpu_data) - sysenter_setup(); +void __init identify_boot_cpu(void) +{ + identify_cpu(&boot_cpu_data); + sysenter_setup(); enable_sep_cpu(); + mtrr_bp_init(); +} - if (c == &boot_cpu_data) - mtrr_bp_init(); - else - mtrr_ap_init(); +void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c) +{ + BUG_ON(c == &boot_cpu_data); + identify_cpu(c); + enable_sep_cpu(); + mtrr_ap_init(); } #ifdef CONFIG_X86_HT -- cgit v1.2.3 From 7a61d35d4b4056e7711031202da7605e052f4137 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 2 May 2007 19:27:15 +0200 Subject: [PATCH] i386: Page-align the GDT Xen wants a dedicated page for the GDT. I believe VMI likes it too. lguest, KVM and native don't care. Simple transformation to page-aligned "struct gdt_page". Signed-off-by: Rusty Russell Signed-off-by: Andi Kleen Acked-by: Jeremy Fitzhardinge --- arch/i386/kernel/cpu/common.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 58128585ae60..7a4c036d93c8 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -22,7 +22,7 @@ #include "cpu.h" -DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = { +DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = { [GDT_ENTRY_KERNEL_CS] = { 0x0000ffff, 0x00cf9a00 }, [GDT_ENTRY_KERNEL_DS] = { 0x0000ffff, 0x00cf9200 }, [GDT_ENTRY_DEFAULT_USER_CS] = { 0x0000ffff, 0x00cffa00 }, @@ -48,8 +48,8 @@ DEFINE_PER_CPU(struct desc_struct, cpu_gdt[GDT_ENTRIES]) = { [GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 }, [GDT_ENTRY_PDA] = { 0x00000000, 0x00c09200 }, /* set in setup_pda */ -}; -EXPORT_PER_CPU_SYMBOL_GPL(cpu_gdt); +} }; +EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); DEFINE_PER_CPU(struct i386_pda, _cpu_pda); EXPORT_PER_CPU_SYMBOL(_cpu_pda); -- cgit v1.2.3 From 7c3576d261ce046789a7db14f43303f8120910c7 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 2 May 2007 19:27:16 +0200 Subject: [PATCH] i386: Convert PDA into the percpu section Currently x86 (similar to x84-64) has a special per-cpu structure called "i386_pda" which can be easily and efficiently referenced via the %fs register. An ELF section is more flexible than a structure, allowing any piece of code to use this area. Indeed, such a section already exists: the per-cpu area. So this patch: (1) Removes the PDA and uses per-cpu variables for each current member. (2) Replaces the __KERNEL_PDA segment with __KERNEL_PERCPU. (3) Creates a per-cpu mirror of __per_cpu_offset called this_cpu_off, which can be used to calculate addresses for this CPU's variables. (4) Simplifies startup, because %fs doesn't need to be loaded with a special segment at early boot; it can be deferred until the first percpu area is allocated (or never for UP). The result is less code and one less x86-specific concept. Signed-off-by: Rusty Russell Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Andi Kleen --- arch/i386/kernel/cpu/common.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 7a4c036d93c8..27e00565f5e4 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -18,7 +18,6 @@ #include #include #endif -#include #include "cpu.h" @@ -47,13 +46,10 @@ DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = { [GDT_ENTRY_APMBIOS_BASE+2] = { 0x0000ffff, 0x00409200 }, /* data */ [GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 }, - [GDT_ENTRY_PDA] = { 0x00000000, 0x00c09200 }, /* set in setup_pda */ + [GDT_ENTRY_PERCPU] = { 0x00000000, 0x00000000 }, } }; EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); -DEFINE_PER_CPU(struct i386_pda, _cpu_pda); -EXPORT_PER_CPU_SYMBOL(_cpu_pda); - static int cachesize_override __cpuinitdata = -1; static int disable_x86_fxsr __cpuinitdata; static int disable_x86_serial_nr __cpuinitdata = 1; @@ -634,21 +630,14 @@ void __init early_cpu_init(void) #endif } -/* Make sure %gs is initialized properly in idle threads */ +/* Make sure %fs is initialized properly in idle threads */ struct pt_regs * __devinit idle_regs(struct pt_regs *regs) { memset(regs, 0, sizeof(struct pt_regs)); - regs->xfs = __KERNEL_PDA; + regs->xfs = __KERNEL_PERCPU; return regs; } -/* Initial PDA used by boot CPU */ -struct i386_pda boot_pda = { - ._pda = &boot_pda, - .cpu_number = 0, - .pcurrent = &init_task, -}; - /* * cpu_init() initializes state that is per-CPU. Some data is already * initialized (naturally) in the bootstrap process, such as the GDT -- cgit v1.2.3 From c5413fbe894924ddb8aa474a4d4da52e7a6c7e0b Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 2 May 2007 19:27:16 +0200 Subject: [PATCH] i386: Fix UP gdt bugs Fixes two problems with the GDT when compiling for uniprocessor: - There's no percpu segment, so trying to load its selector into %fs fails. Use a null selector instead. - The real gdt needs to be loaded at some point. Do it in cpu_init(). Signed-off-by: Chris Wright Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Rusty Russell --- arch/i386/kernel/cpu/common.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'arch/i386/kernel/cpu/common.c') diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 27e00565f5e4..794d593c47eb 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -638,6 +638,18 @@ struct pt_regs * __devinit idle_regs(struct pt_regs *regs) return regs; } +/* 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 Xgt_desc_struct gdt_descr; + + gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id()); + gdt_descr.size = GDT_SIZE - 1; + load_gdt(&gdt_descr); + asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory"); +} + /* * cpu_init() initializes state that is per-CPU. Some data is already * initialized (naturally) in the bootstrap process, such as the GDT @@ -668,6 +680,7 @@ void __cpuinit cpu_init(void) } load_idt(&idt_descr); + switch_to_new_gdt(); /* * Set up and load the per-CPU TSS and LDT -- cgit v1.2.3