2019-04-25 07:15:16

by Atish Patra

[permalink] [raw]
Subject: [PATCH v4 0/4] Miscellaneous kernel command line fixes

Assorted command line option fixes for RISC-V.

Changes from v3->v4.
1. Fixed few checkpatch warnings.

Changes from v2->v3.
1. Merged patch 1 & 2 into one patch.

Changes from v1->v2.
1. Update pr_err string in patch (4/4) as per review.

Atish Patra (4):
RISC-V: Add RISC-V specific arch_match_cpu_phys_id
RISC-V: Implement nosmp commandline option.
RISC-V: Support nr_cpus command line option.
RISC-V: Fix minor checkpatch issues.

arch/riscv/kernel/cpu.c | 3 +--
arch/riscv/kernel/smp.c | 8 +++++++-
arch/riscv/kernel/smpboot. | 0
arch/riscv/kernel/smpboot.c | 22 ++++++++++++++++++++--
4 files changed, 28 insertions(+), 5 deletions(-)
create mode 100644 arch/riscv/kernel/smpboot.

--
2.21.0


2019-04-25 07:15:57

by Atish Patra

[permalink] [raw]
Subject: [PATCH 2/4] RISC-V: Implement nosmp commandline option.

nosmp command line option sets max_cpus to zero. No secondary harts
will boot if this is enabled. But present cpu mask will still point to
all possible masks.

Fix present cpu mask for nosmp usecase.

Signed-off-by: Atish Patra <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
arch/riscv/kernel/smpboot.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index eb533b5c2c8c..a8ad200581aa 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -47,6 +47,17 @@ void __init smp_prepare_boot_cpu(void)

void __init smp_prepare_cpus(unsigned int max_cpus)
{
+ int cpuid;
+
+ /* This covers non-smp usecase mandated by "nosmp" option */
+ if (max_cpus == 0)
+ return;
+
+ for_each_possible_cpu(cpuid) {
+ if (cpuid == smp_processor_id())
+ continue;
+ set_cpu_present(cpuid, true);
+ }
}

void __init setup_smp(void)
@@ -74,7 +85,6 @@ void __init setup_smp(void)

cpuid_to_hartid_map(cpuid) = hart;
set_cpu_possible(cpuid, true);
- set_cpu_present(cpuid, true);
cpuid++;
}

--
2.21.0

2019-04-25 07:16:10

by Atish Patra

[permalink] [raw]
Subject: [PATCH 3/4] RISC-V: Support nr_cpus command line option.

If nr_cpus command line option is set, maximum possible cpu should be
set to that value.

Signed-off-by: Atish Patra <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
arch/riscv/kernel/smpboot. | 0
arch/riscv/kernel/smpboot.c | 10 +++++++++-
2 files changed, 9 insertions(+), 1 deletion(-)
create mode 100644 arch/riscv/kernel/smpboot.

diff --git a/arch/riscv/kernel/smpboot. b/arch/riscv/kernel/smpboot.
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index a8ad200581aa..7a0b62252524 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -84,11 +84,19 @@ void __init setup_smp(void)
}

cpuid_to_hartid_map(cpuid) = hart;
- set_cpu_possible(cpuid, true);
cpuid++;
}

BUG_ON(!found_boot_cpu);
+
+ if (cpuid > nr_cpu_ids)
+ pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n",
+ cpuid, nr_cpu_ids);
+
+ for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
+ if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID)
+ set_cpu_possible(cpuid, true);
+ }
}

int __cpu_up(unsigned int cpu, struct task_struct *tidle)
--
2.21.0

2019-04-25 09:43:59

by Sudeep Holla

[permalink] [raw]
Subject: Re: [PATCH 2/4] RISC-V: Implement nosmp commandline option.

On Wed, Apr 24, 2019 at 02:47:59PM -0700, Atish Patra wrote:
> nosmp command line option sets max_cpus to zero. No secondary harts
> will boot if this is enabled. But present cpu mask will still point to
> all possible masks.
>
> Fix present cpu mask for nosmp usecase.
>
> Signed-off-by: Atish Patra <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>

I just noticed RISC-V has CONFIG_SMP option configurable. ARM64 has
it always on and no option to disable :)

Anyways, this looks good.

Reviewed-by: Sudeep Holla <[email protected]>

--
Regards,
Sudeep

2019-04-25 10:06:09

by Atish Patra

[permalink] [raw]
Subject: [PATCH 4/4] RISC-V: Fix minor checkpatch issues.

While working on the patches, I found some minor checkpatch issues.

Signed-off-by: Atish Patra <[email protected]>
---
arch/riscv/kernel/smp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 89251f8ab754..0115db1368a4 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -42,7 +42,7 @@ unsigned long __cpuid_to_hartid_map[NR_CPUS] = {

void __init smp_setup_processor_id(void)
{
- cpuid_to_hartid_map(0) = boot_cpu_hartid;
+ cpuid_to_hartid_map(0) = boot_cpu_hartid;
}

/* A collection of single bit ipi messages. */
@@ -53,7 +53,7 @@ static struct {

int riscv_hartid_to_cpuid(int hartid)
{
- int i = -1;
+ int i;

for (i = 0; i < NR_CPUS; i++)
if (cpuid_to_hartid_map(i) == hartid)
--
2.21.0

2019-04-25 11:24:47

by Atish Patra

[permalink] [raw]
Subject: [PATCH 1/4] RISC-V: Add RISC-V specific arch_match_cpu_phys_id

OF/DT core has a hook for architecture specific logical cpuid to hartid
mapping. By implementing this, we can pass the logical cpu id to cpu
node parsing functions.

Fix the instances where logical cpuid is expected as an argument in
of_get_cpu_node.

Signed-off-by: Atish Patra <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Sudeep Holla <[email protected]>
---
arch/riscv/kernel/cpu.c | 3 +--
arch/riscv/kernel/smp.c | 6 ++++++
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index cf2fca12414a..c8d2a3223099 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -136,8 +136,7 @@ static void c_stop(struct seq_file *m, void *v)
static int c_show(struct seq_file *m, void *v)
{
unsigned long cpu_id = (unsigned long)v - 1;
- struct device_node *node = of_get_cpu_node(cpuid_to_hartid_map(cpu_id),
- NULL);
+ struct device_node *node = of_get_cpu_node(cpu_id, NULL);
const char *compat, *isa, *mmu;

seq_printf(m, "processor\t: %lu\n", cpu_id);
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 0c41d07ec281..89251f8ab754 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -70,6 +70,12 @@ void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out)
for_each_cpu(cpu, in)
cpumask_set_cpu(cpuid_to_hartid_map(cpu), out);
}
+
+bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
+{
+ return phys_id == cpuid_to_hartid_map(cpu);
+}
+
/* Unsupported */
int setup_profiling_timer(unsigned int multiplier)
{
--
2.21.0

2019-04-25 12:45:36

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH 4/4] RISC-V: Fix minor checkpatch issues.

On Wed, Apr 24, 2019 at 02:48:01PM -0700, Atish Patra wrote:
> While working on the patches, I found some minor checkpatch issues.
>
> Signed-off-by: Atish Patra <[email protected]>

Looks fine,

Reviewed-by: Christoph Hellwig <[email protected]>

2019-04-25 12:48:50

by Sudeep Holla

[permalink] [raw]
Subject: Re: [PATCH 3/4] RISC-V: Support nr_cpus command line option.

On Wed, Apr 24, 2019 at 02:48:00PM -0700, Atish Patra wrote:
> If nr_cpus command line option is set, maximum possible cpu should be
> set to that value.
>
> Signed-off-by: Atish Patra <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>

FWIW,

Reviewed-by: Sudeep Holla <[email protected]>

--
Regards,
Sudeep