Along the lines of what b89f8f054f96 ("x86/apic: Drop sync_Arb_IDs()")
said, the function is dead logic as well: All 64-bit capable Intel systems
have (at least) xAPIC (if not x2APIC).
Even if Eclair can't know it, such code is violating Misra rule 2.2 (dead
code; we didn't accept that yet, but - where possible - we probably would
better follow it). Depending on one's reading, this code may actually be a
violation of rule 2.1 (unreachable), which we did accept:
"Code is unreachable if, ..., there is no combination of program inputs
that can cause it to be executed."
Otoh it's "only" __init code.
Signed-off-by: Jan Beulich <jbeul...@suse.com>
--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -1459,119 +1459,6 @@ void disable_IO_APIC(void)
}
/*
- * function to set the IO-APIC physical IDs based on the
- * values stored in the MPC table.
- *
- * by Matt Domsch <matt_dom...@dell.com> Tue Dec 21 12:25:05 CST 1999
- */
-
-static void __init setup_ioapic_ids_from_mpc(void)
-{
- union IO_APIC_reg_00 reg_00;
- static physid_mask_t __initdata phys_id_present_map;
- int apic;
- int i;
- unsigned char old_id;
- unsigned long flags;
- const uint32_t broadcast_id = 0xf;
-
- /*
- * Don't check I/O APIC IDs for xAPIC systems. They have
- * no meaning without the serial APIC bus.
- */
- if (!(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
- || APIC_XAPIC(apic_version[boot_cpu_physical_apicid]))
- return;
-
- /*
- * This is broken; anything with a real cpu count has to
- * circumvent this idiocy regardless.
- */
- phys_id_present_map = phys_cpu_present_map;
-
- /*
- * Set the IOAPIC ID to the value stored in the MPC table.
- */
- for (apic = 0; apic < nr_ioapics; apic++) {
- if (!nr_ioapic_entries[apic])
- continue;
-
- /* Read the register 0 value */
- spin_lock_irqsave(&ioapic_lock, flags);
- reg_00.raw = io_apic_read(apic, 0);
- spin_unlock_irqrestore(&ioapic_lock, flags);
-
- old_id = mp_ioapics[apic].mpc_apicid;
-
- if (mp_ioapics[apic].mpc_apicid >= broadcast_id) {
- printk(KERN_ERR "BIOS bug, IO-APIC#%d ID is %d in the MPC
table!...\n",
- apic, mp_ioapics[apic].mpc_apicid);
- printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
- reg_00.bits.ID);
- mp_ioapics[apic].mpc_apicid = reg_00.bits.ID;
- }
-
- /*
- * Sanity check, is the ID really free? Every APIC in a
- * system must have a unique ID or we get lots of nice
- * 'stuck on smp_invalidate_needed IPI wait' messages.
- */
- if ( physid_isset(mp_ioapics[apic].mpc_apicid, phys_id_present_map) )
- {
- printk(KERN_ERR "BIOS bug, IO-APIC#%d ID %d is already used!...\n",
- apic, mp_ioapics[apic].mpc_apicid);
- for (i = 0; i < broadcast_id; i++)
- if (!physid_isset(i, phys_id_present_map))
- break;
- if (i >= broadcast_id)
- panic("Max APIC ID exceeded\n");
- printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
- i);
- mp_ioapics[apic].mpc_apicid = i;
- } else {
- apic_printk(APIC_VERBOSE, "Setting %d in the "
- "phys_id_present_map\n",
- mp_ioapics[apic].mpc_apicid);
- }
- physid_set(mp_ioapics[apic].mpc_apicid, phys_id_present_map);
-
- /*
- * We need to adjust the IRQ routing table
- * if the ID changed.
- */
- if (old_id != mp_ioapics[apic].mpc_apicid)
- for (i = 0; i < mp_irq_entries; i++)
- if (mp_irqs[i].mpc_dstapic == old_id)
- mp_irqs[i].mpc_dstapic
- = mp_ioapics[apic].mpc_apicid;
-
- /*
- * Read the right value from the MPC table and
- * write it into the ID register.
- */
- apic_printk(APIC_VERBOSE, KERN_INFO
- "...changing IO-APIC physical APIC ID to %d ...",
- mp_ioapics[apic].mpc_apicid);
-
- reg_00.bits.ID = mp_ioapics[apic].mpc_apicid;
- spin_lock_irqsave(&ioapic_lock, flags);
- io_apic_write(apic, 0, reg_00.raw);
- spin_unlock_irqrestore(&ioapic_lock, flags);
-
- /*
- * Sanity check
- */
- spin_lock_irqsave(&ioapic_lock, flags);
- reg_00.raw = io_apic_read(apic, 0);
- spin_unlock_irqrestore(&ioapic_lock, flags);
- if (reg_00.bits.ID != mp_ioapics[apic].mpc_apicid)
- printk("could not set ID!\n");
- else
- apic_printk(APIC_VERBOSE, " ok.\n");
- }
-}
-
-/*
* There is a nasty bug in some older SMP boards, their mptable lies
* about the timer IRQ. We do the following to work around the situation:
*
@@ -2158,12 +2045,6 @@ void __init setup_IO_APIC(void)
ioapic_level_type.end = end_level_ioapic_irq_new;
}
- /*
- * Set up IO-APIC IRQ routing.
- */
- if (!acpi_ioapic)
- setup_ioapic_ids_from_mpc();
-
setup_IO_APIC_irqs();
init_IO_APIC_traps();
check_timer();
