From: Boris Ostrovsky Date: Wed, 1 Apr 2015 14:12:14 +0000 (-0400) Subject: x86/cpu: Factor out common CPU initialization code, fix 32-bit Xen PV guests X-Git-Tag: firefly_0821_release~176^2~2028^2~30 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3f85483bd80ef1de8cbbf0361be59f6a069b59d4;p=firefly-linux-kernel-4.4.55.git x86/cpu: Factor out common CPU initialization code, fix 32-bit Xen PV guests Some of x86 bare-metal and Xen CPU initialization code is common between the two and therefore can be factored out to avoid code duplication. As a side effect, doing so will also extend the fix provided by commit a7fcf28d431e ("x86/asm/entry: Replace this_cpu_sp0() with current_top_of_stack() to x86_32") to 32-bit Xen PV guests. Signed-off-by: Boris Ostrovsky Reviewed-by: David Vrabel Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Thomas Gleixner Cc: konrad.wilk@oracle.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1427897534-5086-1-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index 8cd1cc3bc835..81d02fc7dafa 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -154,6 +154,7 @@ void cpu_die_common(unsigned int cpu); void native_smp_prepare_boot_cpu(void); void native_smp_prepare_cpus(unsigned int max_cpus); void native_smp_cpus_done(unsigned int max_cpus); +void common_cpu_up(unsigned int cpunum, struct task_struct *tidle); int native_cpu_up(unsigned int cpunum, struct task_struct *tidle); int native_cpu_disable(void); void native_cpu_die(unsigned int cpu); diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 7b20ffd2fffc..5b298a95d567 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -779,6 +779,26 @@ out: return boot_error; } +void common_cpu_up(unsigned int cpu, struct task_struct *idle) +{ + /* Just in case we booted with a single CPU. */ + alternatives_enable_smp(); + + per_cpu(current_task, cpu) = idle; + +#ifdef CONFIG_X86_32 + /* Stack for startup_32 can be just as for start_secondary onwards */ + irq_ctx_init(cpu); + per_cpu(cpu_current_top_of_stack, cpu) = + (unsigned long)task_stack_page(idle) + THREAD_SIZE; +#else + clear_tsk_thread_flag(idle, TIF_FORK); + initial_gs = per_cpu_offset(cpu); +#endif + per_cpu(kernel_stack, cpu) = + (unsigned long)task_stack_page(idle) + THREAD_SIZE; +} + /* * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad * (ie clustered apic addressing mode), this is a LOGICAL apic ID. @@ -796,24 +816,9 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle) int cpu0_nmi_registered = 0; unsigned long timeout; - /* Just in case we booted with a single CPU. */ - alternatives_enable_smp(); - idle->thread.sp = (unsigned long) (((struct pt_regs *) (THREAD_SIZE + task_stack_page(idle))) - 1); - per_cpu(current_task, cpu) = idle; -#ifdef CONFIG_X86_32 - /* Stack for startup_32 can be just as for start_secondary onwards */ - irq_ctx_init(cpu); - per_cpu(cpu_current_top_of_stack, cpu) = - (unsigned long)task_stack_page(idle) + THREAD_SIZE; -#else - clear_tsk_thread_flag(idle, TIF_FORK); - initial_gs = per_cpu_offset(cpu); -#endif - per_cpu(kernel_stack, cpu) = - (unsigned long)task_stack_page(idle) + THREAD_SIZE; early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu); initial_code = (unsigned long)start_secondary; stack_start = idle->thread.sp; @@ -954,6 +959,8 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle) /* the FPU context is blank, nobody can own it */ __cpu_disable_lazy_restore(cpu); + common_cpu_up(cpu, tidle); + err = do_boot_cpu(apicid, cpu, tidle); if (err) { pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu); diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 765b7684f858..7413ee3706d0 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -445,14 +445,7 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle) { int rc; - per_cpu(current_task, cpu) = idle; -#ifdef CONFIG_X86_32 - irq_ctx_init(cpu); -#else - clear_tsk_thread_flag(idle, TIF_FORK); -#endif - per_cpu(kernel_stack, cpu) = - (unsigned long)task_stack_page(idle) + THREAD_SIZE; + common_cpu_up(cpu, idle); xen_setup_runstate_info(cpu); xen_setup_timer(cpu); @@ -467,10 +460,6 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle) if (rc) return rc; - if (num_online_cpus() == 1) - /* Just in case we booted with a single CPU. */ - alternatives_enable_smp(); - rc = xen_smp_intr_init(cpu); if (rc) return rc;