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| author | Thomas Gleixner <tglx@linutronix.de> | 2024-07-28 14:06:10 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-08-09 15:34:16 +0300 |
| commit | 838ba7733e4e3a94a928e8d0a058de1811a58621 (patch) | |
| tree | 79a8ab458ac7bd3759904404735c7a28f39ca1a0 /arch/x86/include | |
| parent | 00e5bd44389145cd2f42be8e98cadb210731e72a (diff) | |
| download | linux-838ba7733e4e3a94a928e8d0a058de1811a58621.tar.xz | |
x86/apic: Remove logical destination mode for 64-bit
Logical destination mode of the local APIC is used for systems with up to
8 CPUs. It has an advantage over physical destination mode as it allows to
target multiple CPUs at once with IPIs.
That advantage was definitely worth it when systems with up to 8 CPUs
were state of the art for servers and workstations, but that's history.
Aside of that there are systems which fail to work with logical destination
mode as the ACPI/DMI quirks show and there are AMD Zen1 systems out there
which fail when interrupt remapping is enabled as reported by Rob and
Christian. The latter problem can be cured by firmware updates, but not all
OEMs distribute the required changes.
Physical destination mode is guaranteed to work because it is the only way
to get a CPU up and running via the INIT/INIT/STARTUP sequence.
As the number of CPUs keeps increasing, logical destination mode becomes a
less used code path so there is no real good reason to keep it around.
Therefore remove logical destination mode support for 64-bit and default to
physical destination mode.
Reported-by: Rob Newcater <rob@durendal.co.uk>
Reported-by: Christian Heusel <christian@heusel.eu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Rob Newcater <rob@durendal.co.uk>
Link: https://lore.kernel.org/all/877cd5u671.ffs@tglx
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/apic.h | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 9dd22ee27117..53f08447193d 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -350,20 +350,12 @@ extern struct apic *apic; * APIC drivers are probed based on how they are listed in the .apicdrivers * section. So the order is important and enforced by the ordering * of different apic driver files in the Makefile. - * - * For the files having two apic drivers, we use apic_drivers() - * to enforce the order with in them. */ #define apic_driver(sym) \ static const struct apic *__apicdrivers_##sym __used \ __aligned(sizeof(struct apic *)) \ __section(".apicdrivers") = { &sym } -#define apic_drivers(sym1, sym2) \ - static struct apic *__apicdrivers_##sym1##sym2[2] __used \ - __aligned(sizeof(struct apic *)) \ - __section(".apicdrivers") = { &sym1, &sym2 } - extern struct apic *__apicdrivers[], *__apicdrivers_end[]; /* |