2024-04-03 23:42:36

by Deepak Gupta

Subject: [PATCH v3 02/29] riscv: define default value for envcfg for task

Defines a base default value for envcfg per task. By default all tasks
should have cache zeroing capability. Any future base capabilities that
apply to all tasks can be turned on same way.

Signed-off-by: Deepak Gupta <[email protected]>
---
arch/riscv/include/asm/csr.h | 2 ++
arch/riscv/kernel/process.c | 6 ++++++
2 files changed, 8 insertions(+)

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 2468c55933cd..bbd2207adb39 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -202,6 +202,8 @@
#define ENVCFG_CBIE_FLUSH _AC(0x1, UL)
#define ENVCFG_CBIE_INV _AC(0x3, UL)
#define ENVCFG_FIOM _AC(0x1, UL)
+/* by default all threads should be able to zero cache */
+#define ENVCFG_BASE ENVCFG_CBZE

/* Smstateen bits */
#define SMSTATEEN0_AIA_IMSIC_SHIFT 58
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 92922dbd5b5c..d3109557f951 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -152,6 +152,12 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
else
regs->status |= SR_UXL_64;
#endif
+ /*
+ * read current envcfg settings, AND it with base settings applicable
+ * for all the tasks. Base settings should've been set up during CPU
+ * bring up.
+ */
+ current->thread_info.envcfg = csr_read(CSR_ENVCFG) & ENVCFG_BASE;
}

void flush_thread(void)
--
2.43.2

2024-05-10 22:33:53

by Charlie Jenkins

Subject: Re: [PATCH v3 02/29] riscv: define default value for envcfg for task

On Wed, Apr 03, 2024 at 04:34:50PM -0700, Deepak Gupta wrote:
> Defines a base default value for envcfg per task. By default all tasks
> should have cache zeroing capability. Any future base capabilities that
> apply to all tasks can be turned on same way.
>
> Signed-off-by: Deepak Gupta <[email protected]>
> ---
> arch/riscv/include/asm/csr.h | 2 ++
> arch/riscv/kernel/process.c | 6 ++++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
> index 2468c55933cd..bbd2207adb39 100644
> --- a/arch/riscv/include/asm/csr.h
> +++ b/arch/riscv/include/asm/csr.h
> @@ -202,6 +202,8 @@
> #define ENVCFG_CBIE_FLUSH _AC(0x1, UL)
> #define ENVCFG_CBIE_INV _AC(0x3, UL)
> #define ENVCFG_FIOM _AC(0x1, UL)
> +/* by default all threads should be able to zero cache */
> +#define ENVCFG_BASE ENVCFG_CBZE
>
> /* Smstateen bits */
> #define SMSTATEEN0_AIA_IMSIC_SHIFT 58
> diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> index 92922dbd5b5c..d3109557f951 100644
> --- a/arch/riscv/kernel/process.c
> +++ b/arch/riscv/kernel/process.c
> @@ -152,6 +152,12 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
> else
> regs->status |= SR_UXL_64;
> #endif
> + /*
> + * read current envcfg settings, AND it with base settings applicable
> + * for all the tasks. Base settings should've been set up during CPU
> + * bring up.
> + */
> + current->thread_info.envcfg = csr_read(CSR_ENVCFG) & ENVCFG_BASE;

This needs to be gated on xlinuxenvcfg.

- Charlie

> }
>
> void flush_thread(void)
> --
> 2.43.2
>

2024-05-13 18:34:12

by Deepak Gupta

Subject: Re: [PATCH v3 02/29] riscv: define default value for envcfg for task

On Fri, May 10, 2024 at 03:33:36PM -0700, Charlie Jenkins wrote:
>On Wed, Apr 03, 2024 at 04:34:50PM -0700, Deepak Gupta wrote:
>> Defines a base default value for envcfg per task. By default all tasks
>> should have cache zeroing capability. Any future base capabilities that
>> apply to all tasks can be turned on same way.
>>
>> Signed-off-by: Deepak Gupta <[email protected]>
>> ---
>> arch/riscv/include/asm/csr.h | 2 ++
>> arch/riscv/kernel/process.c | 6 ++++++
>> 2 files changed, 8 insertions(+)
>>
>> diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
>> index 2468c55933cd..bbd2207adb39 100644
>> --- a/arch/riscv/include/asm/csr.h
>> +++ b/arch/riscv/include/asm/csr.h
>> @@ -202,6 +202,8 @@
>> #define ENVCFG_CBIE_FLUSH _AC(0x1, UL)
>> #define ENVCFG_CBIE_INV _AC(0x3, UL)
>> #define ENVCFG_FIOM _AC(0x1, UL)
>> +/* by default all threads should be able to zero cache */
>> +#define ENVCFG_BASE ENVCFG_CBZE
>>
>> /* Smstateen bits */
>> #define SMSTATEEN0_AIA_IMSIC_SHIFT 58
>> diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
>> index 92922dbd5b5c..d3109557f951 100644
>> --- a/arch/riscv/kernel/process.c
>> +++ b/arch/riscv/kernel/process.c
>> @@ -152,6 +152,12 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
>> else
>> regs->status |= SR_UXL_64;
>> #endif
>> + /*
>> + * read current envcfg settings, AND it with base settings applicable
>> + * for all the tasks. Base settings should've been set up during CPU
>> + * bring up.
>> + */
>> + current->thread_info.envcfg = csr_read(CSR_ENVCFG) & ENVCFG_BASE;
>
>This needs to be gated on xlinuxenvcfg.

You're right. This csr read should be gated on xlinuxenvcfg. Will fix it.

>
>- Charlie
>
>> }
>>
>> void flush_thread(void)
>> --
>> 2.43.2
>>