Thread (2 messages) 2 messages, 2 authors, 2016-10-17

[PATCH] arm64: kernel: numa: fix ACPI boot cpu numa node mapping

From: Laszlo Ersek <hidden>
Date: 2016-10-17 14:32:49
Also in: linux-acpi, lkml

On 10/17/16 16:18, Lorenzo Pieralisi wrote:
Commit 7ba5f605f3a0 ("arm64/numa: remove the limitation that cpu0 must
bind to node0") removed the numa cpu<->node mapping restriction whereby
logical cpu 0 always corresponds to numa node 0; removing the
restriction was correct, in that it does not really exist in practice
but the commit only updated the early mapping of logical cpu 0 to its
real numa node for the DT boot path, missing the ACPI one, leading to
boot failures on ACPI systems with numa enabled owing to missing
node<->cpu map for logical cpu 0.
Small correction request: please drop the "with numa enabled"
qualification. The bug breaks ACPI boot on numa-disabled systems as well
(i.e., where there's only one node, and there are no NUMA-related ACPI
tables (like SRAT) and objects (like _PXM in the DSDT)).

Many thanks!
Laszlo
quoted hunk ↗ jump to hunk
Fix the issue by updating the ACPI boot path with code that carries out
the early cpu<->node mapping also for the boot cpu (ie cpu 0), mirroring
what is currently done in the DT boot path.

Fixes: 7ba5f605f3a0 ("arm64/numa: remove the limitation that cpu0 must bind to node0")
Signed-off-by: Lorenzo Pieralisi <redacted>
Tested-by: Laszlo Ersek <redacted>
Reported-by: Laszlo Ersek <redacted>
Cc: Will Deacon <redacted>
Cc: Laszlo Ersek <redacted>
Cc: Hanjun Guo <redacted>
Cc: Andrew Jones <redacted>
Cc: Zhen Lei <redacted>
Cc: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/kernel/smp.c | 1 +
 1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index d3f151c..8507703 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -544,6 +544,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
 			return;
 		}
 		bootcpu_valid = true;
+		early_map_cpu_to_node(0, acpi_numa_get_nid(0, hwid));
 		return;
 	}
 
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