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[PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe

Yunhui Cui posted 1 patch 1 year, 5 months ago
There is a newer version of this series
Documentation/arch/riscv/hwprobe.rst  | 2 ++
arch/riscv/include/asm/hwprobe.h      | 2 +-
arch/riscv/include/uapi/asm/hwprobe.h | 1 +
arch/riscv/kernel/sys_hwprobe.c       | 5 +++++
4 files changed, 9 insertions(+), 1 deletion(-)
[PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe
Posted by Yunhui Cui 1 year, 5 months ago 
From: Palmer Dabbelt <palmer@rivosinc.com>

A handful of user-visible behavior is based on the frequency of the
time CSR.

Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 Documentation/arch/riscv/hwprobe.rst  | 2 ++
 arch/riscv/include/asm/hwprobe.h      | 2 +-
 arch/riscv/include/uapi/asm/hwprobe.h | 1 +
 arch/riscv/kernel/sys_hwprobe.c       | 5 +++++
 4 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index fc015b452ebf..c07f159d8906 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -229,3 +229,5 @@ The following keys are defined:
 
 * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
   represents the size of the Zicboz block in bytes.
+
+* :c:macro:`RISCV_HWPROBE_KEY_TIME_CSR_FREQ`: Frequency (in Hz) of `mtime`.
diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
index 630507dff5ea..150a9877b0af 100644
--- a/arch/riscv/include/asm/hwprobe.h
+++ b/arch/riscv/include/asm/hwprobe.h
@@ -8,7 +8,7 @@
 
 #include <uapi/asm/hwprobe.h>
 
-#define RISCV_HWPROBE_MAX_KEY 6
+#define RISCV_HWPROBE_MAX_KEY 7
 
 static inline bool riscv_hwprobe_key_is_valid(__s64 key)
 {
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index 7b95fadbea2a..18754341ff14 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -73,6 +73,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_MISALIGNED_UNSUPPORTED	(4 << 0)
 #define		RISCV_HWPROBE_MISALIGNED_MASK		(7 << 0)
 #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE	6
+#define RISCV_HWPROBE_KEY_TIME_CSR_FREQ	7
 /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
 
 /* Flags */
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index 83fcc939df67..fc3b40fb9def 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -8,6 +8,7 @@
 #include <asm/cacheflush.h>
 #include <asm/cpufeature.h>
 #include <asm/hwprobe.h>
+#include <asm/delay.h>
 #include <asm/sbi.h>
 #include <asm/switch_to.h>
 #include <asm/uaccess.h>
@@ -226,6 +227,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
 			pair->value = riscv_cboz_block_size;
 		break;
 
+	case RISCV_HWPROBE_KEY_TIME_CSR_FREQ:
+		pair->value = riscv_timebase;
+		break;
+
 	/*
 	 * For forward compatibility, unknown keys don't fail the whole
 	 * call, but get their element key set to -1 and value set to 0
-- 
2.20.1
Re: [PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe
Posted by Jesse Taube 1 year, 5 months ago 

On 6/21/24 07:31, Yunhui Cui wrote:
> From: Palmer Dabbelt <palmer@rivosinc.com>
> 
> A handful of user-visible behavior is based on the frequency of the
> time CSR.
> 
> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>   Documentation/arch/riscv/hwprobe.rst  | 2 ++
>   arch/riscv/include/asm/hwprobe.h      | 2 +-
>   arch/riscv/include/uapi/asm/hwprobe.h | 1 +
>   arch/riscv/kernel/sys_hwprobe.c       | 5 +++++
>   4 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> index fc015b452ebf..c07f159d8906 100644
> --- a/Documentation/arch/riscv/hwprobe.rst
> +++ b/Documentation/arch/riscv/hwprobe.rst
> @@ -229,3 +229,5 @@ The following keys are defined:
>   
>   * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
>     represents the size of the Zicboz block in bytes.
> +
> +* :c:macro:`RISCV_HWPROBE_KEY_TIME_CSR_FREQ`: Frequency (in Hz) of `mtime`.
> diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> index 630507dff5ea..150a9877b0af 100644
> --- a/arch/riscv/include/asm/hwprobe.h
> +++ b/arch/riscv/include/asm/hwprobe.h
> @@ -8,7 +8,7 @@
>   
>   #include <uapi/asm/hwprobe.h>
>   
> -#define RISCV_HWPROBE_MAX_KEY 6
> +#define RISCV_HWPROBE_MAX_KEY 7

Please rebase onto palmers branch as MAX_KEY is already 7.

https://git.kernel.org/pub/scm/linux/kernel/git/palmer/linux.git/log/?h=for-next

Thanks,
Jesse Taube

>   
>   static inline bool riscv_hwprobe_key_is_valid(__s64 key)
>   {
> diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> index 7b95fadbea2a..18754341ff14 100644
> --- a/arch/riscv/include/uapi/asm/hwprobe.h
> +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> @@ -73,6 +73,7 @@ struct riscv_hwprobe {
>   #define		RISCV_HWPROBE_MISALIGNED_UNSUPPORTED	(4 << 0)
>   #define		RISCV_HWPROBE_MISALIGNED_MASK		(7 << 0)
>   #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE	6
> +#define RISCV_HWPROBE_KEY_TIME_CSR_FREQ	7
>   /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
>   
>   /* Flags */
> diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> index 83fcc939df67..fc3b40fb9def 100644
> --- a/arch/riscv/kernel/sys_hwprobe.c
> +++ b/arch/riscv/kernel/sys_hwprobe.c
> @@ -8,6 +8,7 @@
>   #include <asm/cacheflush.h>
>   #include <asm/cpufeature.h>
>   #include <asm/hwprobe.h>
> +#include <asm/delay.h>
>   #include <asm/sbi.h>
>   #include <asm/switch_to.h>
>   #include <asm/uaccess.h>
> @@ -226,6 +227,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
>   			pair->value = riscv_cboz_block_size;
>   		break;
>   
> +	case RISCV_HWPROBE_KEY_TIME_CSR_FREQ:
> +		pair->value = riscv_timebase;
> +		break;
> +
>   	/*
>   	 * For forward compatibility, unknown keys don't fail the whole
>   	 * call, but get their element key set to -1 and value set to 0
Re: [External] Re: [PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe
Posted by yunhui cui 1 year, 5 months ago 
Hi Jesse,


On Sat, Jun 22, 2024 at 5:25 AM Jesse Taube <jesse@rivosinc.com> wrote:
>
>
>
> On 6/21/24 07:31, Yunhui Cui wrote:
> > From: Palmer Dabbelt <palmer@rivosinc.com>
> >
> > A handful of user-visible behavior is based on the frequency of the
> > time CSR.
> >
> > Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > ---
> >   Documentation/arch/riscv/hwprobe.rst  | 2 ++
> >   arch/riscv/include/asm/hwprobe.h      | 2 +-
> >   arch/riscv/include/uapi/asm/hwprobe.h | 1 +
> >   arch/riscv/kernel/sys_hwprobe.c       | 5 +++++
> >   4 files changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> > index fc015b452ebf..c07f159d8906 100644
> > --- a/Documentation/arch/riscv/hwprobe.rst
> > +++ b/Documentation/arch/riscv/hwprobe.rst
> > @@ -229,3 +229,5 @@ The following keys are defined:
> >
> >   * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
> >     represents the size of the Zicboz block in bytes.
> > +
> > +* :c:macro:`RISCV_HWPROBE_KEY_TIME_CSR_FREQ`: Frequency (in Hz) of `mtime`.
> > diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> > index 630507dff5ea..150a9877b0af 100644
> > --- a/arch/riscv/include/asm/hwprobe.h
> > +++ b/arch/riscv/include/asm/hwprobe.h
> > @@ -8,7 +8,7 @@
> >
> >   #include <uapi/asm/hwprobe.h>
> >
> > -#define RISCV_HWPROBE_MAX_KEY 6
> > +#define RISCV_HWPROBE_MAX_KEY 7
>
> Please rebase onto palmers branch as MAX_KEY is already 7.
>
> https://git.kernel.org/pub/scm/linux/kernel/git/palmer/linux.git/log/?h=for-next
Okay, I will update it on v3, thanks.

>
> Thanks,
> Jesse Taube
>
> >
> >   static inline bool riscv_hwprobe_key_is_valid(__s64 key)
> >   {
> > diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> > index 7b95fadbea2a..18754341ff14 100644
> > --- a/arch/riscv/include/uapi/asm/hwprobe.h
> > +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> > @@ -73,6 +73,7 @@ struct riscv_hwprobe {
> >   #define             RISCV_HWPROBE_MISALIGNED_UNSUPPORTED    (4 << 0)
> >   #define             RISCV_HWPROBE_MISALIGNED_MASK           (7 << 0)
> >   #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE 6
> > +#define RISCV_HWPROBE_KEY_TIME_CSR_FREQ      7
> >   /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
> >
> >   /* Flags */
> > diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> > index 83fcc939df67..fc3b40fb9def 100644
> > --- a/arch/riscv/kernel/sys_hwprobe.c
> > +++ b/arch/riscv/kernel/sys_hwprobe.c
> > @@ -8,6 +8,7 @@
> >   #include <asm/cacheflush.h>
> >   #include <asm/cpufeature.h>
> >   #include <asm/hwprobe.h>
> > +#include <asm/delay.h>
> >   #include <asm/sbi.h>
> >   #include <asm/switch_to.h>
> >   #include <asm/uaccess.h>
> > @@ -226,6 +227,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
> >                       pair->value = riscv_cboz_block_size;
> >               break;
> >
> > +     case RISCV_HWPROBE_KEY_TIME_CSR_FREQ:
> > +             pair->value = riscv_timebase;
> > +             break;
> > +
> >       /*
> >        * For forward compatibility, unknown keys don't fail the whole
> >        * call, but get their element key set to -1 and value set to 0

Thanks,
Yunhui
Re: [PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe
Posted by Jessica Clarke 1 year, 5 months ago 
On 21 Jun 2024, at 12:31, Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> 
> From: Palmer Dabbelt <palmer@rivosinc.com>
> 
> A handful of user-visible behavior is based on the frequency of the
> time CSR.
> 
> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
> Documentation/arch/riscv/hwprobe.rst  | 2 ++
> arch/riscv/include/asm/hwprobe.h      | 2 +-
> arch/riscv/include/uapi/asm/hwprobe.h | 1 +
> arch/riscv/kernel/sys_hwprobe.c       | 5 +++++
> 4 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> index fc015b452ebf..c07f159d8906 100644
> --- a/Documentation/arch/riscv/hwprobe.rst
> +++ b/Documentation/arch/riscv/hwprobe.rst
> @@ -229,3 +229,5 @@ The following keys are defined:
> 
> * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
>   represents the size of the Zicboz block in bytes.
> +
> +* :c:macro:`RISCV_HWPROBE_KEY_TIME_CSR_FREQ`: Frequency (in Hz) of `mtime`.

This still says mtime.

Jess

> diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> index 630507dff5ea..150a9877b0af 100644
> --- a/arch/riscv/include/asm/hwprobe.h
> +++ b/arch/riscv/include/asm/hwprobe.h
> @@ -8,7 +8,7 @@
> 
> #include <uapi/asm/hwprobe.h>
> 
> -#define RISCV_HWPROBE_MAX_KEY 6
> +#define RISCV_HWPROBE_MAX_KEY 7
> 
> static inline bool riscv_hwprobe_key_is_valid(__s64 key)
> {
> diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> index 7b95fadbea2a..18754341ff14 100644
> --- a/arch/riscv/include/uapi/asm/hwprobe.h
> +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> @@ -73,6 +73,7 @@ struct riscv_hwprobe {
> #define RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0)
> #define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0)
> #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE 6
> +#define RISCV_HWPROBE_KEY_TIME_CSR_FREQ 7
> /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
> 
> /* Flags */
> diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> index 83fcc939df67..fc3b40fb9def 100644
> --- a/arch/riscv/kernel/sys_hwprobe.c
> +++ b/arch/riscv/kernel/sys_hwprobe.c
> @@ -8,6 +8,7 @@
> #include <asm/cacheflush.h>
> #include <asm/cpufeature.h>
> #include <asm/hwprobe.h>
> +#include <asm/delay.h>
> #include <asm/sbi.h>
> #include <asm/switch_to.h>
> #include <asm/uaccess.h>
> @@ -226,6 +227,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
> pair->value = riscv_cboz_block_size;
> break;
> 
> + case RISCV_HWPROBE_KEY_TIME_CSR_FREQ:
> + pair->value = riscv_timebase;
> + break;
> +
> /*
> * For forward compatibility, unknown keys don't fail the whole
> * call, but get their element key set to -1 and value set to 0
> -- 
> 2.20.1
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Re: [External] Re: [PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe
Posted by yunhui cui 1 year, 5 months ago 
Hi Jessica,

On Sat, Jun 22, 2024 at 2:04 AM Jessica Clarke <jrtc27@jrtc27.com> wrote:
>
> On 21 Jun 2024, at 12:31, Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> >
> > From: Palmer Dabbelt <palmer@rivosinc.com>
> >
> > A handful of user-visible behavior is based on the frequency of the
> > time CSR.
> >
> > Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > ---
> > Documentation/arch/riscv/hwprobe.rst  | 2 ++
> > arch/riscv/include/asm/hwprobe.h      | 2 +-
> > arch/riscv/include/uapi/asm/hwprobe.h | 1 +
> > arch/riscv/kernel/sys_hwprobe.c       | 5 +++++
> > 4 files changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> > index fc015b452ebf..c07f159d8906 100644
> > --- a/Documentation/arch/riscv/hwprobe.rst
> > +++ b/Documentation/arch/riscv/hwprobe.rst
> > @@ -229,3 +229,5 @@ The following keys are defined:
> >
> > * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
> >   represents the size of the Zicboz block in bytes.
> > +
> > +* :c:macro:`RISCV_HWPROBE_KEY_TIME_CSR_FREQ`: Frequency (in Hz) of `mtime`.
>
> This still says mtime.
Okay, I will update it on v3, thanks.

>
> Jess
>
> > diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> > index 630507dff5ea..150a9877b0af 100644
> > --- a/arch/riscv/include/asm/hwprobe.h
> > +++ b/arch/riscv/include/asm/hwprobe.h
> > @@ -8,7 +8,7 @@
> >
> > #include <uapi/asm/hwprobe.h>
> >
> > -#define RISCV_HWPROBE_MAX_KEY 6
> > +#define RISCV_HWPROBE_MAX_KEY 7
> >
> > static inline bool riscv_hwprobe_key_is_valid(__s64 key)
> > {
> > diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> > index 7b95fadbea2a..18754341ff14 100644
> > --- a/arch/riscv/include/uapi/asm/hwprobe.h
> > +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> > @@ -73,6 +73,7 @@ struct riscv_hwprobe {
> > #define RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0)
> > #define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0)
> > #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE 6
> > +#define RISCV_HWPROBE_KEY_TIME_CSR_FREQ 7
> > /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
> >
> > /* Flags */
> > diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> > index 83fcc939df67..fc3b40fb9def 100644
> > --- a/arch/riscv/kernel/sys_hwprobe.c
> > +++ b/arch/riscv/kernel/sys_hwprobe.c
> > @@ -8,6 +8,7 @@
> > #include <asm/cacheflush.h>
> > #include <asm/cpufeature.h>
> > #include <asm/hwprobe.h>
> > +#include <asm/delay.h>
> > #include <asm/sbi.h>
> > #include <asm/switch_to.h>
> > #include <asm/uaccess.h>
> > @@ -226,6 +227,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
> > pair->value = riscv_cboz_block_size;
> > break;
> >
> > + case RISCV_HWPROBE_KEY_TIME_CSR_FREQ:
> > + pair->value = riscv_timebase;
> > + break;
> > +
> > /*
> > * For forward compatibility, unknown keys don't fail the whole
> > * call, but get their element key set to -1 and value set to 0
> > --
> > 2.20.1
> >
> >
> > _______________________________________________
> > linux-riscv mailing list
> > linux-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-riscv
>

Thanks,
Yunhui
Re: [PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe
Posted by Evan Green 1 year, 5 months ago 
On Fri, Jun 21, 2024 at 4:31 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
>
> From: Palmer Dabbelt <palmer@rivosinc.com>
>
> A handful of user-visible behavior is based on the frequency of the
> time CSR.
>
> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>

Reviewed-by: Evan Green <evan@rivosinc.com>
Re: [PATCH v2] RISC-V: Provide the frequency of time CSR via hwprobe
Posted by Anup Patel 1 year, 5 months ago 
On Fri, Jun 21, 2024 at 5:03 PM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
>
> From: Palmer Dabbelt <palmer@rivosinc.com>
>
> A handful of user-visible behavior is based on the frequency of the
> time CSR.
>
> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>

LGTM.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  Documentation/arch/riscv/hwprobe.rst  | 2 ++
>  arch/riscv/include/asm/hwprobe.h      | 2 +-
>  arch/riscv/include/uapi/asm/hwprobe.h | 1 +
>  arch/riscv/kernel/sys_hwprobe.c       | 5 +++++
>  4 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> index fc015b452ebf..c07f159d8906 100644
> --- a/Documentation/arch/riscv/hwprobe.rst
> +++ b/Documentation/arch/riscv/hwprobe.rst
> @@ -229,3 +229,5 @@ The following keys are defined:
>
>  * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
>    represents the size of the Zicboz block in bytes.
> +
> +* :c:macro:`RISCV_HWPROBE_KEY_TIME_CSR_FREQ`: Frequency (in Hz) of `mtime`.
> diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h
> index 630507dff5ea..150a9877b0af 100644
> --- a/arch/riscv/include/asm/hwprobe.h
> +++ b/arch/riscv/include/asm/hwprobe.h
> @@ -8,7 +8,7 @@
>
>  #include <uapi/asm/hwprobe.h>
>
> -#define RISCV_HWPROBE_MAX_KEY 6
> +#define RISCV_HWPROBE_MAX_KEY 7
>
>  static inline bool riscv_hwprobe_key_is_valid(__s64 key)
>  {
> diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> index 7b95fadbea2a..18754341ff14 100644
> --- a/arch/riscv/include/uapi/asm/hwprobe.h
> +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> @@ -73,6 +73,7 @@ struct riscv_hwprobe {
>  #define                RISCV_HWPROBE_MISALIGNED_UNSUPPORTED    (4 << 0)
>  #define                RISCV_HWPROBE_MISALIGNED_MASK           (7 << 0)
>  #define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE    6
> +#define RISCV_HWPROBE_KEY_TIME_CSR_FREQ        7
>  /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
>
>  /* Flags */
> diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> index 83fcc939df67..fc3b40fb9def 100644
> --- a/arch/riscv/kernel/sys_hwprobe.c
> +++ b/arch/riscv/kernel/sys_hwprobe.c
> @@ -8,6 +8,7 @@
>  #include <asm/cacheflush.h>
>  #include <asm/cpufeature.h>
>  #include <asm/hwprobe.h>
> +#include <asm/delay.h>
>  #include <asm/sbi.h>
>  #include <asm/switch_to.h>
>  #include <asm/uaccess.h>
> @@ -226,6 +227,10 @@ static void hwprobe_one_pair(struct riscv_hwprobe *pair,
>                         pair->value = riscv_cboz_block_size;
>                 break;
>
> +       case RISCV_HWPROBE_KEY_TIME_CSR_FREQ:
> +               pair->value = riscv_timebase;
> +               break;
> +
>         /*
>          * For forward compatibility, unknown keys don't fail the whole
>          * call, but get their element key set to -1 and value set to 0
> --
> 2.20.1
>
>

Patchew 2.1-devel-b67e4c2

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