Re: [patch V3 19/40] x86/apic: Use u32 for wakeup_secondary_cpu[_64]()

From: Qiuxu Zhuo
Date: Thu Aug 10 2023 - 04:03:40 EST


>From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ...
>Subject: [patch V3 19/40] x86/apic: Use u32 for wakeup_secondary_cpu[_64]()
>
>APIC IDs are used with random data types u16, u32, int, unsigned int,
>unsigned long.
>
>Make it all consistently use u32 because that reflects the hardware
>register width.
> ...

Hi Thomas,

Seems some other places (see the diff below) may also need to consistently
use u32 for APIC IDs. If need me to create a separate patch, please let me know.

-Qiuxu

---
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index efa8128437cb..723304e9b4cd 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -514,9 +514,9 @@ extern void generic_bigsmp_probe(void);

extern struct apic apic_noop;

-static inline unsigned int read_apic_id(void)
+static inline u32 read_apic_id(void)
{
- unsigned int reg = apic_read(APIC_ID);
+ u32 reg = apic_read(APIC_ID);

return apic->get_apic_id(reg);
}
@@ -539,7 +539,7 @@ extern u32 default_cpu_present_to_apicid(int mps_cpu);

#else /* CONFIG_X86_LOCAL_APIC */

-static inline unsigned int read_apic_id(void) { return 0; }
+static inline u32 read_apic_id(void) { return 0; }

#endif /* !CONFIG_X86_LOCAL_APIC */

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index f63ab86f6d57..9e235b71b14e 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1728,7 +1728,7 @@ static void __x2apic_enable(void)
static int __init setup_nox2apic(char *str)
{
if (x2apic_enabled()) {
- int apicid = native_apic_msr_read(APIC_ID);
+ u32 apicid = native_apic_msr_read(APIC_ID);

if (apicid >= 255) {
pr_warn("Apicid: %08x, cannot enforce nox2apic\n",
@@ -2354,7 +2354,7 @@ static struct {
*/
int active;
/* r/w apic fields */
- unsigned int apic_id;
+ u32 apic_id;
unsigned int apic_taskpri;
unsigned int apic_ldr;
unsigned int apic_dfr;
diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c
index b54b2a6a4c32..28972a044be2 100644
--- a/arch/x86/kernel/apic/ipi.c
+++ b/arch/x86/kernel/apic/ipi.c
@@ -280,7 +280,7 @@ void default_send_IPI_mask_logical(const struct cpumask *cpumask, int vector)
local_irq_restore(flags);
}

-static int convert_apicid_to_cpu(int apic_id)
+static int convert_apicid_to_cpu(u32 apic_id)
{
int i;

@@ -293,7 +293,8 @@ static int convert_apicid_to_cpu(int apic_id)

int safe_smp_processor_id(void)
{
- int apicid, cpuid;
+ u32 apicid;
+ int cpuid;

if (!boot_cpu_has(X86_FEATURE_APIC))
return 0;