[patch 15/58] x86/apic: Sanitize APIC address setup

From: Thomas Gleixner
Date: Mon Jul 17 2023 - 19:15:47 EST


Convert places which just write mp_lapic_addr and let them register the
local APIC address directly instead of relying on magic other code to do
so.

Add a WARN_ON() into register_lapic_address() which is raised when
register_lapic_address() is invoked more than once during boot.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/apic/apic.c | 25 ++++++++-----------------
1 file changed, 8 insertions(+), 17 deletions(-)

--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2009,12 +2009,12 @@ static bool __init detect_init_APIC(void
return false;
}

- mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
+ register_lapic_address(APIC_DEFAULT_PHYS_BASE);
return true;
}
#else

-static bool __init apic_verify(void)
+static bool __init apic_verify(unsigned long addr)
{
u32 features, h, l;

@@ -2028,15 +2028,15 @@ static bool __init apic_verify(void)
return false;
}
set_cpu_cap(&boot_cpu_data, X86_FEATURE_APIC);
- mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;

/* The BIOS may have set up the APIC at some other address */
if (boot_cpu_data.x86 >= 6) {
rdmsr(MSR_IA32_APICBASE, l, h);
if (l & MSR_IA32_APICBASE_ENABLE)
- mp_lapic_addr = l & MSR_IA32_APICBASE_BASE;
+ addr = l & MSR_IA32_APICBASE_BASE;
}

+ register_lapic_address(addr);
pr_info("Found and enabled local APIC!\n");
return true;
}
@@ -2063,7 +2063,7 @@ bool __init apic_force_enable(unsigned l
enabled_via_apicbase = 1;
}
}
- return apic_verify();
+ return apic_verify(addr);
}

/*
@@ -2105,7 +2105,7 @@ static bool __init detect_init_APIC(void
if (!apic_force_enable(APIC_DEFAULT_PHYS_BASE))
return false;
} else {
- if (!apic_verify())
+ if (!apic_verify(APIC_DEFAULT_PHYS_BASE))
return false;
}

@@ -2130,20 +2130,9 @@ void __init init_apic_mappings(void)
if (x2apic_mode)
return;

- /* If no local APIC can be found return early */
if (!smp_found_config && !detect_init_APIC()) {
- /* lets NOP'ify apic operations */
pr_info("APIC: disable apic facility\n");
apic_disable();
- } else {
- apic_phys = mp_lapic_addr;
-
- /*
- * If the system has ACPI MADT tables or MP info, the LAPIC
- * address is already registered.
- */
- if (!acpi_lapic && !smp_found_config)
- register_lapic_address(apic_phys);
}
}

@@ -2158,6 +2147,8 @@ static __init void apic_set_fixmap(void)

void __init register_lapic_address(unsigned long address)
{
+ /* This should only happen once */
+ WARN_ON_ONCE(mp_lapic_addr);
mp_lapic_addr = address;

if (!x2apic_mode)