[PATCH] sep initializing rework

Make SEP init per-cpu, so it is hotplug safe.

Signed-off-by: Li Shaohua<shaohua.li@intel.com>
Signed-off-by: NAshok Raj <ashok.raj@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/i386/kernel/cpu/common.c

@@ -432,6 +432,9 @@ void __init identify_cpu(struct cpuinfo_x86 *c)
 #ifdef CONFIG_X86_MCE
 	mcheck_init(c);
 #endif
+	if (c == &boot_cpu_data)
+		sysenter_setup();
+	enable_sep_cpu();
 }
 
 #ifdef CONFIG_X86_HT

arch/i386/kernel/smp.c

@@ -495,6 +495,16 @@ struct call_data_struct {
 	int wait;
 };
 
+void lock_ipi_call_lock(void)
+{
+	spin_lock_irq(&call_lock);
+}
+
+void unlock_ipi_call_lock(void)
+{
+	spin_unlock_irq(&call_lock);
+}
+
 static struct call_data_struct * call_data;
 
 /*

arch/i386/kernel/smpboot.c

@@ -449,7 +449,18 @@ static void __init start_secondary(void *unused)
 	 * the local TLBs too.
 	 */
 	local_flush_tlb();
+
+	/*
+	 * We need to hold call_lock, so there is no inconsistency
+	 * between the time smp_call_function() determines number of
+	 * IPI receipients, and the time when the determination is made
+	 * for which cpus receive the IPI. Holding this
+	 * lock helps us to not include this cpu in a currently in progress
+	 * smp_call_function().
+	 */
+	lock_ipi_call_lock();
 	cpu_set(smp_processor_id(), cpu_online_map);
+	unlock_ipi_call_lock();
 
 	/* We can take interrupts now: we're officially "up". */
 	local_irq_enable();

arch/i386/kernel/sysenter.c

@@ -21,11 +21,16 @@
 
 extern asmlinkage void sysenter_entry(void);
 
-void enable_sep_cpu(void *info)
+void enable_sep_cpu(void)
 {
 	int cpu = get_cpu();
 	struct tss_struct *tss = &per_cpu(init_tss, cpu);
 
+	if (!boot_cpu_has(X86_FEATURE_SEP)) {
+		put_cpu();
+		return;
+	}
+
 	tss->ss1 = __KERNEL_CS;
 	tss->esp1 = sizeof(struct tss_struct) + (unsigned long) tss;
 	wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
@@ -41,7 +46,7 @@ void enable_sep_cpu(void *info)
 extern const char vsyscall_int80_start, vsyscall_int80_end;
 extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
 
-static int __init sysenter_setup(void)
+int __init sysenter_setup(void)
 {
 	void *page = (void *)get_zeroed_page(GFP_ATOMIC);
 
@@ -58,8 +63,5 @@ static int __init sysenter_setup(void)
 	       &vsyscall_sysenter_start,
 	       &vsyscall_sysenter_end - &vsyscall_sysenter_start);
 
-	on_each_cpu(enable_sep_cpu, NULL, 1, 1);
 	return 0;
 }
-
-__initcall(sysenter_setup);

arch/i386/power/cpu.c

@@ -22,9 +22,11 @@
 #include <linux/device.h>
 #include <linux/suspend.h>
 #include <linux/acpi.h>
+
 #include <asm/uaccess.h>
 #include <asm/acpi.h>
 #include <asm/tlbflush.h>
+#include <asm/processor.h>
 
 static struct saved_context saved_context;
 
@@ -33,8 +35,6 @@ unsigned long saved_context_esp, saved_context_ebp;
 unsigned long saved_context_esi, saved_context_edi;
 unsigned long saved_context_eflags;
 
-extern void enable_sep_cpu(void *);
-
 void __save_processor_state(struct saved_context *ctxt)
 {
 	kernel_fpu_begin();
@@ -136,7 +136,7 @@ void __restore_processor_state(struct saved_context *ctxt)
 	 * sysenter MSRs
 	 */
 	if (boot_cpu_has(X86_FEATURE_SEP))
-		enable_sep_cpu(NULL);
+		enable_sep_cpu();
 
 	fix_processor_context();
 	do_fpu_end();

include/asm-i386/processor.h

@@ -691,5 +691,7 @@ extern void select_idle_routine(const struct cpuinfo_x86 *c);
 #define cache_line_size() (boot_cpu_data.x86_cache_alignment)
 
 extern unsigned long boot_option_idle_override;
+extern void enable_sep_cpu(void);
+extern int sysenter_setup(void);
 
 #endif /* __ASM_I386_PROCESSOR_H */

include/asm-i386/smp.h

@@ -42,6 +42,8 @@ extern void smp_message_irq(int cpl, void *dev_id, struct pt_regs *regs);
 extern void smp_invalidate_rcv(void);		/* Process an NMI */
 extern void (*mtrr_hook) (void);
 extern void zap_low_mappings (void);
+extern void lock_ipi_call_lock(void);
+extern void unlock_ipi_call_lock(void);
 
 #define MAX_APICID 256
 extern u8 x86_cpu_to_apicid[];