x86/apic/32: Remove x86_cpu_to_logical_apicid

This per CPU variable is just yet another form of voodoo programming. The
boot ordering is:

  per_cpu(x86_cpu_to_logical_apicid, cpu) = 1U << cpu;

  .....

  setup_apic()
     apic->init_apic_ldr()
       default_init_apic_ldr()
         apic_write(SET_APIC_LOGICAL_ID(1UL << smp_processor_id(), APIC_LDR);

     id = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR);
     WARN_ON(id != per_cpu(x86_cpu_to_logical_apicid, cpu));
     per_cpu(x86_cpu_to_logical_apicid, cpu) = id;

So first write the default into LDR and then validate it against the same default
which was set up during early boot APIC enumeration.

Brilliant, isn't it?

The comment above the per CPU variable declaration describes it well:
'Let's keep it ugly for now.'

Remove the useless gunk and use '1U << cpu' consistently all over the place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 8d96d9a6962de2dbf724faf4699a23eafe7d6537..8ece65b63b64bd1c533cf1a2c79b6c3ce8a16ab2 100644 (file)
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -22,9 +22,6 @@ DECLARE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id);
 
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid);
 DECLARE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid);
-#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
-DECLARE_EARLY_PER_CPU_READ_MOSTLY(int, x86_cpu_to_logical_apicid);
-#endif
 
 struct task_struct;
 

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 89f2a7e5a9f57412ab6d9ac72178ce681fb531e7..224dff4b9258dc8c8b4de70a5bf9b6205c8070f4 100644 (file)
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -113,15 +113,6 @@ EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid);
 
 #ifdef CONFIG_X86_32
-
-/*
- * On x86_32, the mapping between cpu and logical apicid may vary
- * depending on apic in use.  The following early percpu variable is
- * used for the mapping.  This is where the behaviors of x86_64 and 32
- * actually diverge.  Let's keep it ugly for now.
- */
-DEFINE_EARLY_PER_CPU_READ_MOSTLY(int, x86_cpu_to_logical_apicid, BAD_APICID);
-
 /* Local APIC was disabled by the BIOS and enabled by the kernel */
 static int enabled_via_apicbase __ro_after_init;
 
@@ -1589,24 +1580,6 @@ static void setup_local_APIC(void)
         */
        apic->init_apic_ldr();
 
-#ifdef CONFIG_X86_32
-       if (apic->dest_mode_logical) {
-               int logical_apicid, ldr_apicid;
-
-               /*
-                * APIC LDR is initialized.  If logical_apicid mapping was
-                * initialized during get_smp_config(), make sure it matches
-                * the actual value.
-                */
-               logical_apicid = early_per_cpu(x86_cpu_to_logical_apicid, cpu);
-               ldr_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
-               if (logical_apicid != BAD_APICID)
-                       WARN_ON(logical_apicid != ldr_apicid);
-               /* Always use the value from LDR. */
-               early_per_cpu(x86_cpu_to_logical_apicid, cpu) = ldr_apicid;
-       }
-#endif
-
        /*
         * Set Task Priority to 'accept all except vectors 0-31'.  An APIC
         * vector in the 16-31 range could be delivered if TPR == 0, but we
@@ -2433,10 +2406,6 @@ static void cpu_update_apic(int cpu, int apicid)
 {
 #if defined(CONFIG_SMP) || defined(CONFIG_X86_64)
        early_per_cpu(x86_cpu_to_apicid, cpu) = apicid;
-#endif
-#ifdef CONFIG_X86_32
-       if (cpu < 8)
-               early_per_cpu(x86_cpu_to_logical_apicid, cpu) = 1U << cpu;
 #endif
        set_cpu_possible(cpu, true);
        physid_set(apicid, phys_cpu_present_map);

diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c
index 29273e0151fc9ecac7e7af12825777429ea41991..aa51e16cb7d866b77181f8f7ed75bf9658816e41 100644 (file)
--- a/arch/x86/kernel/apic/ipi.c
+++ b/arch/x86/kernel/apic/ipi.c
@@ -243,50 +243,32 @@ void default_send_IPI_self(int vector)
 }
 
 #ifdef CONFIG_X86_32
-
-void default_send_IPI_mask_sequence_logical(const struct cpumask *mask,
-                                                int vector)
+void default_send_IPI_mask_sequence_logical(const struct cpumask *mask, int vector)
 {
        unsigned long flags;
-       unsigned int query_cpu;
-
-       /*
-        * Hack. The clustered APIC addressing mode doesn't allow us to send
-        * to an arbitrary mask, so I do a unicasts to each CPU instead. This
-        * should be modified to do 1 message per cluster ID - mbligh
-        */
+       unsigned int cpu;
 
        local_irq_save(flags);
-       for_each_cpu(query_cpu, mask)
-               __default_send_IPI_dest_field(
-                       early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
-                       vector, APIC_DEST_LOGICAL);
+       for_each_cpu(cpu, mask)
+               __default_send_IPI_dest_field(1U << cpu, vector, APIC_DEST_LOGICAL);
        local_irq_restore(flags);
 }
 
 void default_send_IPI_mask_allbutself_logical(const struct cpumask *mask,
                                                 int vector)
 {
+       unsigned int cpu, this_cpu = smp_processor_id();
        unsigned long flags;
-       unsigned int query_cpu;
-       unsigned int this_cpu = smp_processor_id();
-
-       /* See Hack comment above */
 
        local_irq_save(flags);
-       for_each_cpu(query_cpu, mask) {
-               if (query_cpu == this_cpu)
+       for_each_cpu(cpu, mask) {
+               if (cpu == this_cpu)
                        continue;
-               __default_send_IPI_dest_field(
-                       early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
-                       vector, APIC_DEST_LOGICAL);
-               }
+               __default_send_IPI_dest_field(1U << cpu, vector, APIC_DEST_LOGICAL);
+       }
        local_irq_restore(flags);
 }
 
-/*
- * This is only used on smaller machines.
- */
 void default_send_IPI_mask_logical(const struct cpumask *cpumask, int vector)
 {
        unsigned long mask = cpumask_bits(cpumask)[0];

diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index f6767d255c3291486879af3c53a5f4ddb49bd58e..2c97bf7b56ae4d095d375d84c6c3e274d70675f1 100644 (file)
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -184,10 +184,6 @@ void __init setup_per_cpu_areas(void)
                per_cpu(x86_cpu_to_acpiid, cpu) =
                        early_per_cpu_map(x86_cpu_to_acpiid, cpu);
 #endif
-#ifdef CONFIG_X86_32
-               per_cpu(x86_cpu_to_logical_apicid, cpu) =
-                       early_per_cpu_map(x86_cpu_to_logical_apicid, cpu);
-#endif
 #ifdef CONFIG_NUMA
                per_cpu(x86_cpu_to_node_map, cpu) =
                        early_per_cpu_map(x86_cpu_to_node_map, cpu);
@@ -214,9 +210,6 @@ void __init setup_per_cpu_areas(void)
        early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
        early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
 #endif
-#ifdef CONFIG_X86_32
-       early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
-#endif
 #ifdef CONFIG_NUMA
        early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 #endif