[patch V3 20/22] x86/apic: Remove the pointless writeback of boot_cpu_physical_apicid

From: Thomas Gleixner
Date: Tue Feb 13 2024 - 16:13:52 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

There is absolutely no point to write the APIC ID which was read from the
local APIC earlier, back into the local APIC for the 64-bit UP case.

Remove that along with the apic callback which is solely there for this
pointless exercise.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>


---
arch/x86/include/asm/apic.h | 1 -
arch/x86/kernel/apic/apic.c | 3 ---
arch/x86/kernel/apic/apic_flat_64.c | 7 -------
arch/x86/kernel/apic/apic_numachip.c | 12 ------------
arch/x86/kernel/apic/bigsmp_32.c | 1 -
arch/x86/kernel/apic/local.h | 1 -
arch/x86/kernel/apic/x2apic_cluster.c | 1 -
arch/x86/kernel/apic/x2apic_phys.c | 6 ------
arch/x86/kernel/apic/x2apic_uv_x.c | 6 ------
arch/x86/xen/apic.c | 7 -------
10 files changed, 45 deletions(-)
---

--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -294,7 +294,6 @@ struct apic {
u32 (*cpu_present_to_apicid)(int mps_cpu);

u32 (*get_apic_id)(u32 id);
- u32 (*set_apic_id)(u32 apicid);

/* wakeup_secondary_cpu */
int (*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip);
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2485,9 +2485,6 @@ EXPORT_SYMBOL_GPL(x86_msi_msg_get_destid

static void __init apic_bsp_up_setup(void)
{
-#ifdef CONFIG_X86_64
- apic_write(APIC_ID, apic->set_apic_id(boot_cpu_physical_apicid));
-#endif
reset_phys_cpu_present_map(boot_cpu_physical_apicid);
}

--- a/arch/x86/kernel/apic/apic_flat_64.c
+++ b/arch/x86/kernel/apic/apic_flat_64.c
@@ -61,11 +61,6 @@ static u32 flat_get_apic_id(u32 x)
return (x >> 24) & 0xFF;
}

-static u32 set_apic_id(u32 id)
-{
- return (id & 0xFF) << 24;
-}
-
static int flat_probe(void)
{
return 1;
@@ -86,7 +81,6 @@ static struct apic apic_flat __ro_after_

.max_apic_id = 0xFE,
.get_apic_id = flat_get_apic_id,
- .set_apic_id = set_apic_id,

.calc_dest_apicid = apic_flat_calc_apicid,

@@ -155,7 +149,6 @@ static struct apic apic_physflat __ro_af

.max_apic_id = 0xFE,
.get_apic_id = flat_get_apic_id,
- .set_apic_id = set_apic_id,

.calc_dest_apicid = apic_default_calc_apicid,

--- a/arch/x86/kernel/apic/apic_numachip.c
+++ b/arch/x86/kernel/apic/apic_numachip.c
@@ -38,11 +38,6 @@ static u32 numachip1_get_apic_id(u32 x)
return id;
}

-static u32 numachip1_set_apic_id(u32 id)
-{
- return (id & 0xff) << 24;
-}
-
static u32 numachip2_get_apic_id(u32 x)
{
u64 mcfg;
@@ -51,11 +46,6 @@ static u32 numachip2_get_apic_id(u32 x)
return ((mcfg >> (28 - 8)) & 0xfff00) | (x >> 24);
}

-static u32 numachip2_set_apic_id(u32 id)
-{
- return id << 24;
-}
-
static void numachip1_apic_icr_write(int apicid, unsigned int val)
{
write_lcsr(CSR_G3_EXT_IRQ_GEN, (apicid << 16) | val);
@@ -225,7 +215,6 @@ static const struct apic apic_numachip1

.max_apic_id = UINT_MAX,
.get_apic_id = numachip1_get_apic_id,
- .set_apic_id = numachip1_set_apic_id,

.calc_dest_apicid = apic_default_calc_apicid,

@@ -260,7 +249,6 @@ static const struct apic apic_numachip2

.max_apic_id = UINT_MAX,
.get_apic_id = numachip2_get_apic_id,
- .set_apic_id = numachip2_set_apic_id,

.calc_dest_apicid = apic_default_calc_apicid,

--- a/arch/x86/kernel/apic/bigsmp_32.c
+++ b/arch/x86/kernel/apic/bigsmp_32.c
@@ -72,7 +72,6 @@ static struct apic apic_bigsmp __ro_afte

.max_apic_id = 0xFE,
.get_apic_id = bigsmp_get_apic_id,
- .set_apic_id = NULL,

.calc_dest_apicid = apic_default_calc_apicid,

--- a/arch/x86/kernel/apic/local.h
+++ b/arch/x86/kernel/apic/local.h
@@ -16,7 +16,6 @@
/* X2APIC */
void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
u32 x2apic_get_apic_id(u32 id);
-u32 x2apic_set_apic_id(u32 id);

void x2apic_send_IPI_all(int vector);
void x2apic_send_IPI_allbutself(int vector);
--- a/arch/x86/kernel/apic/x2apic_cluster.c
+++ b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -237,7 +237,6 @@ static struct apic apic_x2apic_cluster _
.max_apic_id = UINT_MAX,
.x2apic_set_max_apicid = true,
.get_apic_id = x2apic_get_apic_id,
- .set_apic_id = x2apic_set_apic_id,

.calc_dest_apicid = x2apic_calc_apicid,

--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -129,11 +129,6 @@ u32 x2apic_get_apic_id(u32 id)
return id;
}

-u32 x2apic_set_apic_id(u32 id)
-{
- return id;
-}
-
static struct apic apic_x2apic_phys __ro_after_init = {

.name = "physical x2apic",
@@ -149,7 +144,6 @@ static struct apic apic_x2apic_phys __ro
.max_apic_id = UINT_MAX,
.x2apic_set_max_apicid = true,
.get_apic_id = x2apic_get_apic_id,
- .set_apic_id = x2apic_set_apic_id,

.calc_dest_apicid = apic_default_calc_apicid,

--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -745,11 +745,6 @@ static void uv_send_IPI_all(int vector)
uv_send_IPI_mask(cpu_online_mask, vector);
}

-static u32 set_apic_id(u32 id)
-{
- return id;
-}
-
static int uv_probe(void)
{
return apic == &apic_x2apic_uv_x;
@@ -769,7 +764,6 @@ static struct apic apic_x2apic_uv_x __ro

.max_apic_id = UINT_MAX,
.get_apic_id = x2apic_get_apic_id,
- .set_apic_id = set_apic_id,

.calc_dest_apicid = apic_default_calc_apicid,

--- a/arch/x86/xen/apic.c
+++ b/arch/x86/xen/apic.c
@@ -33,12 +33,6 @@ static unsigned int xen_io_apic_read(uns
return 0xfd;
}

-static u32 xen_set_apic_id(u32 x)
-{
- WARN_ON(1);
- return x;
-}
-
static u32 xen_get_apic_id(u32 x)
{
return ((x)>>24) & 0xFFu;
@@ -131,7 +125,6 @@ static struct apic xen_pv_apic __ro_afte

.max_apic_id = UINT_MAX,
.get_apic_id = xen_get_apic_id,
- .set_apic_id = xen_set_apic_id,

.calc_dest_apicid = apic_flat_calc_apicid,