[tip: x86/apic] x86/apic: Remove redundant check from x2apic_phys_probe()

[tip-bot2 for Grzegorz Jaszczyk]

The following commit has been merged into the x86/apic branch of tip:

Commit-ID:     98dff3f1bc033da4d4811d8f335fe7311dbf54df
Gitweb:        https://git.kernel.org/tip/98dff3f1bc033da4d4811d8f335fe7311dbf54df
Author:        Grzegorz Jaszczyk <jaszczyk@xxxxxxxxxxxx>
AuthorDate:    Thu, 24 Sep 2026 10:40:20 
Committer:     Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Mon, 19 Oct 2026 18:21:25 -07:00

x86/apic: Remove redundant check from x2apic_phys_probe()

Commit

  9ebd680bd029 ("x86, apic: Use probe routines to simplify apic selection")

introduced x2apic_phys_probe() with a generic fallback check for

  apic == &apic_x2apic_phys

to preserve any prior selection of apic_x2apic_phys by default_acpi_madt_oem_check().

At the time, x2apic_acpi_madt_oem_check() only checked

  x2apic_phys && x2apic_enabled()

so that fallback was already redundant. Commit

  ea0dcf903e7d ("x86/apic: Use x2apic physical mode based on FADT setting")

later added the ACPI_FADT_APIC_PHYSICAL check only to x2apic_acpi_madt_oem_check(),
temporarily relying on the fallback in x2apic_phys_probe() when x2APIC was
pre-enabled by BIOS.

Subsequently,

  cb214ede7657 ("x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems")

factored out x2apic_fadt_phys() and added it directly to x2apic_phys_probe(). Because
default_acpi_madt_oem_check() (via the .acpi_madt_oem_check callback) is the only
path that can install apic_x2apic_phys prior to x2apic_phys_probe(), and
x2apic_acpi_madt_oem_check() checks the exact same

  x2apic_phys || x2apic_fadt_phys()

condition, the fallback

  apic == &apic_x2apic_phys

check became completely unreachable again.

Remove the redundant check and the associated forward declaration of apic_x2apic_phys.

In addition to cleaning up dead code, this allows apic_x2apic_phys to be installed as
an early boot default driver when hardware x2APIC is pre-enabled without preventing
x2apic_cluster from being probed and selected later during boot.

  [ bp: Massage commit message. ]

Signed-off-by: Grzegorz Jaszczyk <jaszczyk@xxxxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxx>
Link: https://patch.msgid.link/20260924104102.3534474-4-jaszczyk@xxxxxxxxxxxx
---
 arch/x86/kernel/apic/x2apic_phys.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index 090647c..5bf8683 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -6,8 +6,6 @@
 #include "local.h"
 
 int x2apic_phys;
-
-static struct apic apic_x2apic_phys;
 u32 x2apic_max_apicid __ro_after_init = UINT_MAX;
 
 void __init x2apic_set_max_apicid(u32 apicid)
@@ -110,10 +108,7 @@ static int x2apic_phys_probe(void)
 	if (!x2apic_mode)
 		return 0;
 
-	if (x2apic_phys || x2apic_fadt_phys())
-		return 1;
-
-	return apic == &apic_x2apic_phys;
+	return x2apic_phys || x2apic_fadt_phys();
 }
 
 u32 x2apic_get_apic_id(u32 id)