commit 456797da792fa7cbf6698febf275fe9b36691f78 upstream.
arm64's method of defining a default cpu topology requires only minimal
changes to apply to RISC-V also. The current arm64 implementation exits
early in a uniprocessor configuration by reading MPIDR & claiming that
uniprocessor can rely on the default values.
This is appears to be a hangover from prior to '3102bc0e6ac7 ("arm64:
topology: Stop using MPIDR for topology information")', because the
current code just assigns default values for multiprocessor systems.
With the MPIDR references removed, store_cpu_topolgy() can be moved to
the common arch_topology code.
Reviewed-by: Sudeep Holla <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Reviewed-by: Atish Patra <[email protected]>
Signed-off-by: Conor Dooley <[email protected]>
---
arch/arm64/kernel/topology.c | 40 ------------------------------------
drivers/base/arch_topology.c | 19 +++++++++++++++++
2 files changed, 19 insertions(+), 40 deletions(-)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 4358bc319306..f35af19b7055 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -22,46 +22,6 @@
#include <asm/cputype.h>
#include <asm/topology.h>
-void store_cpu_topology(unsigned int cpuid)
-{
- struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
- u64 mpidr;
-
- if (cpuid_topo->package_id != -1)
- goto topology_populated;
-
- mpidr = read_cpuid_mpidr();
-
- /* Uniprocessor systems can rely on default topology values */
- if (mpidr & MPIDR_UP_BITMASK)
- return;
-
- /*
- * This would be the place to create cpu topology based on MPIDR.
- *
- * However, it cannot be trusted to depict the actual topology; some
- * pieces of the architecture enforce an artificial cap on Aff0 values
- * (e.g. GICv3's ICC_SGI1R_EL1 limits it to 15), leading to an
- * artificial cycling of Aff1, Aff2 and Aff3 values. IOW, these end up
- * having absolutely no relationship to the actual underlying system
- * topology, and cannot be reasonably used as core / package ID.
- *
- * If the MT bit is set, Aff0 *could* be used to define a thread ID, but
- * we still wouldn't be able to obtain a sane core ID. This means we
- * need to entirely ignore MPIDR for any topology deduction.
- */
- cpuid_topo->thread_id = -1;
- cpuid_topo->core_id = cpuid;
- cpuid_topo->package_id = cpu_to_node(cpuid);
-
- pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
- cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
- cpuid_topo->thread_id, mpidr);
-
-topology_populated:
- update_siblings_masks(cpuid);
-}
-
#ifdef CONFIG_ACPI
static bool __init acpi_cpu_is_threaded(int cpu)
{
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 8272a3a002a3..51647926e605 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -596,4 +596,23 @@ void __init init_cpu_topology(void)
else if (of_have_populated_dt() && parse_dt_topology())
reset_cpu_topology();
}
+
+void store_cpu_topology(unsigned int cpuid)
+{
+ struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
+
+ if (cpuid_topo->package_id != -1)
+ goto topology_populated;
+
+ cpuid_topo->thread_id = -1;
+ cpuid_topo->core_id = cpuid;
+ cpuid_topo->package_id = cpu_to_node(cpuid);
+
+ pr_debug("CPU%u: package %d core %d thread %d\n",
+ cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
+ cpuid_topo->thread_id);
+
+topology_populated:
+ update_siblings_masks(cpuid);
+}
#endif
--
2.38.0
commit fbd92809997a391f28075f1c8b5ee314c225557c upstream.
RISC-V has no sane defaults to fall back on where there is no cpu-map
in the devicetree.
Without sane defaults, the package, core and thread IDs are all set to
-1. This causes user-visible inaccuracies for tools like hwloc/lstopo
which rely on the sysfs cpu topology files to detect a system's
topology.
On a PolarFire SoC, which should have 4 harts with a thread each,
lstopo currently reports:
Machine (793MB total)
Package L#0
NUMANode L#0 (P#0 793MB)
Core L#0
L1d L#0 (32KB) + L1i L#0 (32KB) + PU L#0 (P#0)
L1d L#1 (32KB) + L1i L#1 (32KB) + PU L#1 (P#1)
L1d L#2 (32KB) + L1i L#2 (32KB) + PU L#2 (P#2)
L1d L#3 (32KB) + L1i L#3 (32KB) + PU L#3 (P#3)
Adding calls to store_cpu_topology() in {boot,smp} hart bringup code
results in the correct topolgy being reported:
Machine (793MB total)
Package L#0
NUMANode L#0 (P#0 793MB)
L1d L#0 (32KB) + L1i L#0 (32KB) + Core L#0 + PU L#0 (P#0)
L1d L#1 (32KB) + L1i L#1 (32KB) + Core L#1 + PU L#1 (P#1)
L1d L#2 (32KB) + L1i L#2 (32KB) + Core L#2 + PU L#2 (P#2)
L1d L#3 (32KB) + L1i L#3 (32KB) + Core L#3 + PU L#3 (P#3)
CC: [email protected] # 456797da792f: arm64: topology: move store_cpu_topology() to shared code
Fixes: 03f11f03dbfe ("RISC-V: Parse cpu topology during boot.")
Reported-by: Brice Goglin <[email protected]>
Link: https://github.com/open-mpi/hwloc/issues/536
Reviewed-by: Sudeep Holla <[email protected]>
Reviewed-by: Atish Patra <[email protected]>
Signed-off-by: Conor Dooley <[email protected]>
---
I just resolved the conflicts, which was mainly removing mentions of
NUMA. Tested in QEMU only.
---
arch/riscv/Kconfig | 2 +-
arch/riscv/kernel/smpboot.c | 4 +++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 1b894c327578..557c4a8c4087 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -35,7 +35,7 @@ config RISCV
select CLINT_TIMER if !MMU
select COMMON_CLK
select EDAC_SUPPORT
- select GENERIC_ARCH_TOPOLOGY if SMP
+ select GENERIC_ARCH_TOPOLOGY
select GENERIC_ATOMIC64 if !64BIT
select GENERIC_CLOCKEVENTS
select GENERIC_EARLY_IOREMAP
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 0b04e0eae3ab..0e0aed380e28 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -46,6 +46,8 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
int cpuid;
int ret;
+ store_cpu_topology(smp_processor_id());
+
/* This covers non-smp usecase mandated by "nosmp" option */
if (max_cpus == 0)
return;
@@ -152,8 +154,8 @@ asmlinkage __visible void smp_callin(void)
mmgrab(mm);
current->active_mm = mm;
+ store_cpu_topology(curr_cpuid);
notify_cpu_starting(curr_cpuid);
- update_siblings_masks(curr_cpuid);
set_cpu_online(curr_cpuid, 1);
/*
--
2.38.0
On Wed, Oct 19, 2022 at 01:53:02PM +0100, Conor Dooley wrote:
> commit 456797da792fa7cbf6698febf275fe9b36691f78 upstream.
All now queued up, thanks.
greg k-h