x86/smp: Move cpu number to percpu hot section

No functional change.

Signed-off-by: Brian Gerst <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>
Acked-by: Uros Bizjak <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/x86/include/asm/current.h

···
 
 struct pcpu_hot {
 	struct task_struct	*current_task;
-	int			cpu_number;
 #ifdef CONFIG_MITIGATION_CALL_DEPTH_TRACKING
 	u64			call_depth;
 #endif

arch/x86/include/asm/smp.h

···
 #include <linux/thread_info.h>
 
 #include <asm/cpumask.h>
-#include <asm/current.h>
+
+DECLARE_PER_CPU_CACHE_HOT(int, cpu_number);
 
 DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
 DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
···
  * This function is needed by all SMP systems. It must _always_ be valid
  * from the initial startup.
  */
-#define raw_smp_processor_id()  this_cpu_read(pcpu_hot.cpu_number)
-#define __smp_processor_id() __this_cpu_read(pcpu_hot.cpu_number)
+#define raw_smp_processor_id()  this_cpu_read(cpu_number)
+#define __smp_processor_id() __this_cpu_read(cpu_number)
 
 static inline struct cpumask *cpu_llc_shared_mask(int cpu)
 {

arch/x86/kernel/setup_percpu.c

···
 #include <asm/cpumask.h>
 #include <asm/cpu.h>
 
+DEFINE_PER_CPU_CACHE_HOT(int, cpu_number);
+EXPORT_PER_CPU_SYMBOL(cpu_number);
+
 DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off);
 EXPORT_PER_CPU_SYMBOL(this_cpu_off);
 
···
 	for_each_possible_cpu(cpu) {
 		per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
 		per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
-		per_cpu(pcpu_hot.cpu_number, cpu) = cpu;
+		per_cpu(cpu_number, cpu) = cpu;
 		setup_percpu_segment(cpu);
 		/*
 		 * Copy data used in early init routines from the

kernel/bpf/verifier.c

···
 		if (insn->imm == BPF_FUNC_get_smp_processor_id &&
 		    verifier_inlines_helper_call(env, insn->imm)) {
 			/* BPF_FUNC_get_smp_processor_id inlining is an
-			 * optimization, so if pcpu_hot.cpu_number is ever
+			 * optimization, so if cpu_number is ever
 			 * changed in some incompatible and hard to support
 			 * way, it's fine to back out this inlining logic
 			 */
 #ifdef CONFIG_SMP
-			insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, (u32)(unsigned long)&pcpu_hot.cpu_number);
+			insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, (u32)(unsigned long)&cpu_number);
 			insn_buf[1] = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0);
 			insn_buf[2] = BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0);
 			cnt = 3;