[patch 3/9] x86/cpu: Unify cpu_init()

Thomas Gleixner
2019-11-06T20:56:50Z

Similar to copy_thread_tls() the 32bit and 64bit implementations of
cpu_init() are very similar and unification avoids duplicate changes in the
future.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/cpu/common.c | 172 ++++++++++++++++---------------------------
1 file changed, 66 insertions(+), 106 deletions(-)

--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1749,7 +1749,7 @@ static void wait_for_master_cpu(int cpu)
}

#ifdef CONFIG_X86_64
-static void setup_getcpu(int cpu)
+static inline void setup_getcpu(int cpu)
{
unsigned long cpudata = vdso_encode_cpunode(cpu, early_cpu_to_node(cpu));
struct desc_struct d = { };
@@ -1769,7 +1769,43 @@ static void setup_getcpu(int cpu)

write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_CPUNODE, &d, DESCTYPE_S);
}
+
+static inline void ucode_cpu_init(int cpu)
+{
+ if (cpu)
+ load_ucode_ap();
+}
+
+static inline void tss_setup_ist(struct tss_struct *tss)
+{
+ /* Set up the per-CPU TSS IST stacks */
+ tss->x86_tss.ist[IST_INDEX_DF] = __this_cpu_ist_top_va(DF);
+ tss->x86_tss.ist[IST_INDEX_NMI] = __this_cpu_ist_top_va(NMI);
+ tss->x86_tss.ist[IST_INDEX_DB] = __this_cpu_ist_top_va(DB);
+ tss->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE);
+}
+
+static inline void gdt_setup_doublefault_tss(int cpu) { }
+
+#else /* CONFIG_X86_64 */
+
+static inline void setup_getcpu(int cpu) { }
+
+static inline void ucode_cpu_init(int cpu)
+{
+ show_ucode_info_early();
+}
+
+static inline void tss_setup_ist(struct tss_struct *tss) { }
+
+static inline void gdt_setup_doublefault_tss(int cpu)
+{
+#ifdef CONFIG_DOUBLEFAULT
+ /* Set up the doublefault TSS pointer in the GDT */
+ __set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
#endif
+}
+#endif /* !CONFIG_X86_64 */

/*
* cpu_init() initializes state that is per-CPU. Some data is already
@@ -1777,21 +1813,15 @@ static void setup_getcpu(int cpu)
* and IDT. We reload them nevertheless, this function acts as a
* 'CPU state barrier', nothing should get across.
*/
-#ifdef CONFIG_X86_64
-
void cpu_init(void)
{
+ struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
+ struct task_struct *cur = current;
int cpu = raw_smp_processor_id();
- struct task_struct *me;
- struct tss_struct *t;
- int i;

wait_for_master_cpu(cpu);

- if (cpu)
- load_ucode_ap();
-
- t = &per_cpu(cpu_tss_rw, cpu);
+ ucode_cpu_init(cpu);

#ifdef CONFIG_NUMA
if (this_cpu_read(numa_node) == 0 &&
@@ -1800,63 +1830,48 @@ void cpu_init(void)
#endif
setup_getcpu(cpu);

- me = current;
-
pr_debug("Initializing CPU#%d\n", cpu);

- cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
+ if (IS_ENABLED(CONFIG_X86_64) || cpu_feature_enabled(X86_FEATURE_VME) ||
+ boot_cpu_has(X86_FEATURE_TSC) || boot_cpu_has(X86_FEATURE_DE))
+ cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);

/*
* Initialize the per-CPU GDT with the boot GDT,
* and set up the GDT descriptor:
*/
-
switch_to_new_gdt(cpu);
- loadsegment(fs, 0);
-
load_current_idt();

- memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
- syscall_init();
-
- wrmsrl(MSR_FS_BASE, 0);
- wrmsrl(MSR_KERNEL_GS_BASE, 0);
- barrier();
+ if (IS_ENABLED(CONFIG_X86_64)) {
+ loadsegment(fs, 0);
+ memset(cur->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
+ syscall_init();
+
+ wrmsrl(MSR_FS_BASE, 0);
+ wrmsrl(MSR_KERNEL_GS_BASE, 0);
+ barrier();

- x86_configure_nx();
- x2apic_setup();
-
- /*
- * set up and load the per-CPU TSS
- */
- if (!t->x86_tss.ist[0]) {
- t->x86_tss.ist[IST_INDEX_DF] = __this_cpu_ist_top_va(DF);
- t->x86_tss.ist[IST_INDEX_NMI] = __this_cpu_ist_top_va(NMI);
- t->x86_tss.ist[IST_INDEX_DB] = __this_cpu_ist_top_va(DB);
- t->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE);
+ x2apic_setup();
}

- t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
-
- /*
- * <= is required because the CPU will access up to
- * 8 bits beyond the end of the IO permission bitmap.
- */
- for (i = 0; i <= IO_BITMAP_LONGS; i++)
- t->io_bitmap[i] = ~0UL;
-
mmgrab(&init_mm);
- me->active_mm = &init_mm;
- BUG_ON(me->mm);
+ cur->active_mm = &init_mm;
+ BUG_ON(cur->mm);
initialize_tlbstate_and_flush();
- enter_lazy_tlb(&init_mm, me);
+ enter_lazy_tlb(&init_mm, cur);

- /*
- * Initialize the TSS. sp0 points to the entry trampoline stack
- * regardless of what task is running.
- */
+ /* Initialize the TSS. */
+ tss_setup_ist(tss);
+ tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
+ memset(tss->io_bitmap, 0xff, sizeof(tss->io_bitmap));
set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
+
load_TR_desc();
+ /*
+ * sp0 points to the entry trampoline stack regardless of what task
+ * is running.
+ */
load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1));

load_mm_ldt(&init_mm);
@@ -1864,6 +1879,8 @@ void cpu_init(void)
clear_all_debug_regs();
dbg_restore_debug_regs();

+ gdt_setup_doublefault_tss(cpu);
+
fpu__init_cpu();

if (is_uv_system())
@@ -1872,63 +1889,6 @@ void cpu_init(void)
load_fixmap_gdt(cpu);
}

-#else
-
-void cpu_init(void)
-{
- int cpu = smp_processor_id();
- struct task_struct *curr = current;
- struct tss_struct *t = &per_cpu(cpu_tss_rw, cpu);
-
- wait_for_master_cpu(cpu);
-
- show_ucode_info_early();
-
- pr_info("Initializing CPU#%d\n", cpu);
-
- if (cpu_feature_enabled(X86_FEATURE_VME) ||
- boot_cpu_has(X86_FEATURE_TSC) ||
- boot_cpu_has(X86_FEATURE_DE))
- cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
-
- load_current_idt();
- switch_to_new_gdt(cpu);
-
- /*
- * Set up and load the per-CPU TSS and LDT
- */
- mmgrab(&init_mm);
- curr->active_mm = &init_mm;
- BUG_ON(curr->mm);
- initialize_tlbstate_and_flush();
- enter_lazy_tlb(&init_mm, curr);
-
- /*
- * Initialize the TSS. sp0 points to the entry trampoline stack
- * regardless of what task is running.
- */
- set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
- load_TR_desc();
- load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1));
-
- load_mm_ldt(&init_mm);
-
- t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
-
-#ifdef CONFIG_DOUBLEFAULT
- /* Set up doublefault TSS pointer in the GDT */
- __set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
-#endif
-
- clear_all_debug_regs();
- dbg_restore_debug_regs();
-
- fpu__init_cpu();
-
- load_fixmap_gdt(cpu);
-}
-#endif
-
/*
* The microcode loader calls this upon late microcode load to recheck features,
* only when microcode has been updated. Caller holds microcode_mutex and CPU