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[PATCH] riscv: print hartid on bringup

Yunhui Cui posted 1 patch 1 year ago
There is a newer version of this series
arch/riscv/kernel/smp.c     | 2 ++
arch/riscv/kernel/smpboot.c | 4 ++++
2 files changed, 6 insertions(+)
[PATCH] riscv: print hartid on bringup
Posted by Yunhui Cui 1 year ago 
Firmware randomly releases cores, so CPU numbers don't linearly map
to hartids. When the system has an exception, we care more about hartids.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 arch/riscv/kernel/smp.c     | 2 ++
 arch/riscv/kernel/smpboot.c | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index d58b5e751286..e650dec44817 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -48,6 +48,8 @@ EXPORT_SYMBOL_GPL(__cpuid_to_hartid_map);
 void __init smp_setup_processor_id(void)
 {
 	cpuid_to_hartid_map(0) = boot_cpu_hartid;
+
+	pr_info("Booting Linux on hartid %lu\n", boot_cpu_hartid);
 }
 
 static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index e36d20205bd7..beba0efb00b9 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -231,6 +231,10 @@ asmlinkage __visible void smp_callin(void)
 	riscv_ipi_enable();
 
 	numa_add_cpu(curr_cpuid);
+
+	pr_info("CPU%u: Booted secondary hartid %lu\n", curr_cpuid,
+		cpuid_to_hartid_map(curr_cpuid));
+
 	set_cpu_online(curr_cpuid, true);
 
 	/*
-- 
2.39.2
Re: [PATCH] riscv: print hartid on bringup
Posted by yunhui cui 11 months, 3 weeks ago 
Hi All,

Gentle ping. Any comments on this patch?

On Sat, Feb 1, 2025 at 7:06 PM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
>
> Firmware randomly releases cores, so CPU numbers don't linearly map
> to hartids. When the system has an exception, we care more about hartids.
>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>  arch/riscv/kernel/smp.c     | 2 ++
>  arch/riscv/kernel/smpboot.c | 4 ++++
>  2 files changed, 6 insertions(+)
>
> diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
> index d58b5e751286..e650dec44817 100644
> --- a/arch/riscv/kernel/smp.c
> +++ b/arch/riscv/kernel/smp.c
> @@ -48,6 +48,8 @@ EXPORT_SYMBOL_GPL(__cpuid_to_hartid_map);
>  void __init smp_setup_processor_id(void)
>  {
>         cpuid_to_hartid_map(0) = boot_cpu_hartid;
> +
> +       pr_info("Booting Linux on hartid %lu\n", boot_cpu_hartid);
>  }
>
>  static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index e36d20205bd7..beba0efb00b9 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -231,6 +231,10 @@ asmlinkage __visible void smp_callin(void)
>         riscv_ipi_enable();
>
>         numa_add_cpu(curr_cpuid);
> +
> +       pr_info("CPU%u: Booted secondary hartid %lu\n", curr_cpuid,
> +               cpuid_to_hartid_map(curr_cpuid));
> +
>         set_cpu_online(curr_cpuid, true);
>
>         /*
> --
> 2.39.2
>

Thanks,
Yunhui
Re: [PATCH] riscv: print hartid on bringup
Posted by Alexandre Ghiti 11 months, 2 weeks ago 
Hi Yunhui,

On Thu, Feb 20, 2025 at 1:54 PM yunhui cui <cuiyunhui@bytedance.com> wrote:
>
> Hi All,
>
> Gentle ping. Any comments on this patch?
>
> On Sat, Feb 1, 2025 at 7:06 PM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> >
> > Firmware randomly releases cores, so CPU numbers don't linearly map
> > to hartids. When the system has an exception, we care more about hartids.
> >
> > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > ---
> >  arch/riscv/kernel/smp.c     | 2 ++
> >  arch/riscv/kernel/smpboot.c | 4 ++++
> >  2 files changed, 6 insertions(+)
> >
> > diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
> > index d58b5e751286..e650dec44817 100644
> > --- a/arch/riscv/kernel/smp.c
> > +++ b/arch/riscv/kernel/smp.c
> > @@ -48,6 +48,8 @@ EXPORT_SYMBOL_GPL(__cpuid_to_hartid_map);
> >  void __init smp_setup_processor_id(void)
> >  {
> >         cpuid_to_hartid_map(0) = boot_cpu_hartid;
> > +
> > +       pr_info("Booting Linux on hartid %lu\n", boot_cpu_hartid);
> >  }
> >
> >  static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
> > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> > index e36d20205bd7..beba0efb00b9 100644
> > --- a/arch/riscv/kernel/smpboot.c
> > +++ b/arch/riscv/kernel/smpboot.c
> > @@ -231,6 +231,10 @@ asmlinkage __visible void smp_callin(void)
> >         riscv_ipi_enable();
> >
> >         numa_add_cpu(curr_cpuid);
> > +
> > +       pr_info("CPU%u: Booted secondary hartid %lu\n", curr_cpuid,
> > +               cpuid_to_hartid_map(curr_cpuid));
> > +
> >         set_cpu_online(curr_cpuid, true);
> >
> >         /*
> > --
> > 2.39.2
> >
>
> Thanks,
> Yunhui

IIRC that's a debug feature when you can't reach userspace and use
cpuinfo, so what about using pr_debug() instead?

Thanks,

Alex
Re: [External] Re: [PATCH] riscv: print hartid on bringup
Posted by yunhui cui 11 months, 2 weeks ago 
Hi Alex,

On Wed, Feb 26, 2025 at 10:58 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>
> Hi Yunhui,
>
> On Thu, Feb 20, 2025 at 1:54 PM yunhui cui <cuiyunhui@bytedance.com> wrote:
> >
> > Hi All,
> >
> > Gentle ping. Any comments on this patch?
> >
> > On Sat, Feb 1, 2025 at 7:06 PM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> > >
> > > Firmware randomly releases cores, so CPU numbers don't linearly map
> > > to hartids. When the system has an exception, we care more about hartids.
> > >
> > > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > > ---
> > >  arch/riscv/kernel/smp.c     | 2 ++
> > >  arch/riscv/kernel/smpboot.c | 4 ++++
> > >  2 files changed, 6 insertions(+)
> > >
> > > diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
> > > index d58b5e751286..e650dec44817 100644
> > > --- a/arch/riscv/kernel/smp.c
> > > +++ b/arch/riscv/kernel/smp.c
> > > @@ -48,6 +48,8 @@ EXPORT_SYMBOL_GPL(__cpuid_to_hartid_map);
> > >  void __init smp_setup_processor_id(void)
> > >  {
> > >         cpuid_to_hartid_map(0) = boot_cpu_hartid;
> > > +
> > > +       pr_info("Booting Linux on hartid %lu\n", boot_cpu_hartid);
> > >  }
> > >
> > >  static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
> > > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> > > index e36d20205bd7..beba0efb00b9 100644
> > > --- a/arch/riscv/kernel/smpboot.c
> > > +++ b/arch/riscv/kernel/smpboot.c
> > > @@ -231,6 +231,10 @@ asmlinkage __visible void smp_callin(void)
> > >         riscv_ipi_enable();
> > >
> > >         numa_add_cpu(curr_cpuid);
> > > +
> > > +       pr_info("CPU%u: Booted secondary hartid %lu\n", curr_cpuid,
> > > +               cpuid_to_hartid_map(curr_cpuid));
> > > +
> > >         set_cpu_online(curr_cpuid, true);
> > >
> > >         /*
> > > --
> > > 2.39.2
> > >
> >
> > Thanks,
> > Yunhui
>
> IIRC that's a debug feature when you can't reach userspace and use
> cpuinfo, so what about using pr_debug() instead?

Using pr_debug needs enabling #define DEBUG in
arch/riscv/kernel/smpboot.c and adding loglevel=8 to cmdline, not
convenient. Can't always cat /proc/cpuinfo before running in user
mode.
It's true that pr_info prints a large amount of information in the
startup logs, especially when there are many CPU cores.

Do you have a better solution?


> Thanks,
>
> Alex

Thanks,
Yunhui
Re: [External] Re: [PATCH] riscv: print hartid on bringup
Posted by Alexandre Ghiti 11 months, 2 weeks ago 
Hi Yunhui,

On Fri, Feb 28, 2025 at 7:41 AM yunhui cui <cuiyunhui@bytedance.com> wrote:
>
> Hi Alex,
>
> On Wed, Feb 26, 2025 at 10:58 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
> >
> > Hi Yunhui,
> >
> > On Thu, Feb 20, 2025 at 1:54 PM yunhui cui <cuiyunhui@bytedance.com> wrote:
> > >
> > > Hi All,
> > >
> > > Gentle ping. Any comments on this patch?
> > >
> > > On Sat, Feb 1, 2025 at 7:06 PM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> > > >
> > > > Firmware randomly releases cores, so CPU numbers don't linearly map
> > > > to hartids. When the system has an exception, we care more about hartids.
> > > >
> > > > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > > > ---
> > > >  arch/riscv/kernel/smp.c     | 2 ++
> > > >  arch/riscv/kernel/smpboot.c | 4 ++++
> > > >  2 files changed, 6 insertions(+)
> > > >
> > > > diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
> > > > index d58b5e751286..e650dec44817 100644
> > > > --- a/arch/riscv/kernel/smp.c
> > > > +++ b/arch/riscv/kernel/smp.c
> > > > @@ -48,6 +48,8 @@ EXPORT_SYMBOL_GPL(__cpuid_to_hartid_map);
> > > >  void __init smp_setup_processor_id(void)
> > > >  {
> > > >         cpuid_to_hartid_map(0) = boot_cpu_hartid;
> > > > +
> > > > +       pr_info("Booting Linux on hartid %lu\n", boot_cpu_hartid);
> > > >  }
> > > >
> > > >  static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
> > > > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> > > > index e36d20205bd7..beba0efb00b9 100644
> > > > --- a/arch/riscv/kernel/smpboot.c
> > > > +++ b/arch/riscv/kernel/smpboot.c
> > > > @@ -231,6 +231,10 @@ asmlinkage __visible void smp_callin(void)
> > > >         riscv_ipi_enable();
> > > >
> > > >         numa_add_cpu(curr_cpuid);
> > > > +
> > > > +       pr_info("CPU%u: Booted secondary hartid %lu\n", curr_cpuid,
> > > > +               cpuid_to_hartid_map(curr_cpuid));
> > > > +
> > > >         set_cpu_online(curr_cpuid, true);
> > > >
> > > >         /*
> > > > --
> > > > 2.39.2
> > > >
> > >
> > > Thanks,
> > > Yunhui
> >
> > IIRC that's a debug feature when you can't reach userspace and use
> > cpuinfo, so what about using pr_debug() instead?
>
> Using pr_debug needs enabling #define DEBUG in
> arch/riscv/kernel/smpboot.c and adding loglevel=8 to cmdline, not
> convenient.

You can also use a kernel command line parameter to enable a
pr_debug() statement
https://www.kernel.org/doc/html/latest/admin-guide/dynamic-debug-howto.html#debug-messages-during-boot-process

Alex

> Can't always cat /proc/cpuinfo before running in user
> mode.
> It's true that pr_info prints a large amount of information in the
> startup logs, especially when there are many CPU cores.
>
> Do you have a better solution?
>
>
> > Thanks,
> >
> > Alex
>
> Thanks,
> Yunhui
Re: [External] Re: [PATCH] riscv: print hartid on bringup
Posted by yunhui cui 11 months, 1 week ago 
Hi Alex,

On Fri, Feb 28, 2025 at 4:19 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>
> Hi Yunhui,
>
> On Fri, Feb 28, 2025 at 7:41 AM yunhui cui <cuiyunhui@bytedance.com> wrote:
> >
> > Hi Alex,
> >
> > On Wed, Feb 26, 2025 at 10:58 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
> > >
> > > Hi Yunhui,
> > >
> > > On Thu, Feb 20, 2025 at 1:54 PM yunhui cui <cuiyunhui@bytedance.com> wrote:
> > > >
> > > > Hi All,
> > > >
> > > > Gentle ping. Any comments on this patch?
> > > >
> > > > On Sat, Feb 1, 2025 at 7:06 PM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> > > > >
> > > > > Firmware randomly releases cores, so CPU numbers don't linearly map
> > > > > to hartids. When the system has an exception, we care more about hartids.
> > > > >
> > > > > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > > > > ---
> > > > >  arch/riscv/kernel/smp.c     | 2 ++
> > > > >  arch/riscv/kernel/smpboot.c | 4 ++++
> > > > >  2 files changed, 6 insertions(+)
> > > > >
> > > > > diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
> > > > > index d58b5e751286..e650dec44817 100644
> > > > > --- a/arch/riscv/kernel/smp.c
> > > > > +++ b/arch/riscv/kernel/smp.c
> > > > > @@ -48,6 +48,8 @@ EXPORT_SYMBOL_GPL(__cpuid_to_hartid_map);
> > > > >  void __init smp_setup_processor_id(void)
> > > > >  {
> > > > >         cpuid_to_hartid_map(0) = boot_cpu_hartid;
> > > > > +
> > > > > +       pr_info("Booting Linux on hartid %lu\n", boot_cpu_hartid);
> > > > >  }
> > > > >
> > > > >  static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
> > > > > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> > > > > index e36d20205bd7..beba0efb00b9 100644
> > > > > --- a/arch/riscv/kernel/smpboot.c
> > > > > +++ b/arch/riscv/kernel/smpboot.c
> > > > > @@ -231,6 +231,10 @@ asmlinkage __visible void smp_callin(void)
> > > > >         riscv_ipi_enable();
> > > > >
> > > > >         numa_add_cpu(curr_cpuid);
> > > > > +
> > > > > +       pr_info("CPU%u: Booted secondary hartid %lu\n", curr_cpuid,
> > > > > +               cpuid_to_hartid_map(curr_cpuid));
> > > > > +
> > > > >         set_cpu_online(curr_cpuid, true);
> > > > >
> > > > >         /*
> > > > > --
> > > > > 2.39.2
> > > > >
> > > >
> > > > Thanks,
> > > > Yunhui
> > >
> > > IIRC that's a debug feature when you can't reach userspace and use
> > > cpuinfo, so what about using pr_debug() instead?
> >
> > Using pr_debug needs enabling #define DEBUG in
> > arch/riscv/kernel/smpboot.c and adding loglevel=8 to cmdline, not
> > convenient.
>
> You can also use a kernel command line parameter to enable a
> pr_debug() statement
> https://www.kernel.org/doc/html/latest/admin-guide/dynamic-debug-howto.html#debug-messages-during-boot-process

Umm, it works. I'll update v2.

>
> Alex
>
> > Can't always cat /proc/cpuinfo before running in user
> > mode.
> > It's true that pr_info prints a large amount of information in the
> > startup logs, especially when there are many CPU cores.
> >
> > Do you have a better solution?
> >
> >
> > > Thanks,
> > >
> > > Alex
> >
> > Thanks,
> > Yunhui

Thanks,
Yunhui

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