[PATCH RFC 2/3] arm64: smp: Pass CPU ID to update_cpu_boot_status()

[Jinjie Ruan]

To support CONFIG_HOTPLUG_PARALLEL, the CPU boot status tracking must
be refactored from a single global variable (secondary_data.status)
to a per-CPU tracking structure to prevent multi-core race conditions.

Add a 'cpu' parameter to update_cpu_boot_status() and update all its
callsites to pass the corresponding CPU ID. This allows updating the
boot status at a per-CPU granularity during parallel bringup.

Signed-off-by: Jinjie Ruan <ruanjinjie at huawei.com>
---
 arch/arm64/include/asm/smp.h   | 6 +++---
 arch/arm64/kernel/cpufeature.c | 2 +-
 arch/arm64/kernel/smp.c        | 8 ++++----
 arch/arm64/mm/context.c        | 2 +-
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
index 10ea4f543069..e2151a01731f 100644
--- a/arch/arm64/include/asm/smp.h
+++ b/arch/arm64/include/asm/smp.h
@@ -122,7 +122,7 @@ static inline void __noreturn cpu_park_loop(void)
 	}
 }
 
-static inline void update_cpu_boot_status(int val)
+static inline void update_cpu_boot_status(unsigned int cpu, int val)
 {
 	WRITE_ONCE(secondary_data.status, val);
 	/* Ensure the visibility of the status update */
@@ -134,9 +134,9 @@ static inline void update_cpu_boot_status(int val)
  * which calls for a kernel panic. Update the boot status and park the calling
  * CPU.
  */
-static inline void __noreturn cpu_panic_kernel(void)
+static inline void __noreturn cpu_panic_kernel(unsigned int cpu)
 {
-	update_cpu_boot_status(CPU_PANIC_KERNEL);
+	update_cpu_boot_status(cpu, CPU_PANIC_KERNEL);
 	cpu_park_loop();
 }
 
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6d53bb15cf7b..0552202702bf 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3674,7 +3674,7 @@ static void verify_local_cpu_caps(u16 scope_mask)
 			caps->desc, system_has_cap, cpu_has_cap);
 
 		if (cpucap_panic_on_conflict(caps))
-			cpu_panic_kernel();
+			cpu_panic_kernel(smp_processor_id());
 		else
 			cpu_die_early();
 	}
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 24f8448e1fbb..6bc90ee4820a 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -118,7 +118,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
 	 * page tables.
 	 */
 	secondary_data.task = idle;
-	update_cpu_boot_status(CPU_MMU_OFF);
+	update_cpu_boot_status(cpu, CPU_MMU_OFF);
 
 	/* Now bring the CPU into our world */
 	ret = boot_secondary(cpu, idle);
@@ -252,7 +252,7 @@ asmlinkage notrace void secondary_start_kernel(void)
 	pr_info("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n",
 					 cpu, (unsigned long)mpidr,
 					 read_cpuid_id());
-	update_cpu_boot_status(CPU_BOOT_SUCCESS);
+	update_cpu_boot_status(cpu, CPU_BOOT_SUCCESS);
 	set_cpu_online(cpu, true);
 	complete(&cpu_running);
 
@@ -411,11 +411,11 @@ void __noreturn cpu_die_early(void)
 	rcutree_report_cpu_dead();
 
 	if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
-		update_cpu_boot_status(CPU_KILL_ME);
+		update_cpu_boot_status(cpu, CPU_KILL_ME);
 		__cpu_try_die(cpu);
 	}
 
-	update_cpu_boot_status(CPU_STUCK_IN_KERNEL);
+	update_cpu_boot_status(cpu, CPU_STUCK_IN_KERNEL);
 
 	cpu_park_loop();
 }
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index 0f4a28b87469..6b8a3245f393 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -72,7 +72,7 @@ void verify_cpu_asid_bits(void)
 		 */
 		pr_crit("CPU%d: smaller ASID size(%u) than boot CPU (%u)\n",
 				smp_processor_id(), asid, asid_bits);
-		cpu_panic_kernel();
+		cpu_panic_kernel(smp_processor_id());
 	}
 }
 
-- 
2.34.1