Re: [PATCH v6 07/21] RISC-V: Add Sscfg extension CSR definition

From: Atish Patra <atish.patra@linux.dev>
To: Charlie Jenkins <thecharlesjenkins@gmail.com>
Cc: James Clark <james.clark@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@kernel.org>, Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Anup Patel <anup@brainfault.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Paul Walmsley <pjw@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Ian Rogers <irogers@google.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-perf-users@vger.kernel.org, Conor Dooley <conor@kernel.org>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v6 07/21] RISC-V: Add Sscfg extension CSR definition
Date: Wed, 24 Jun 2026 00:36:17 -0700	[thread overview]
Message-ID: <85b09fd7-f849-46e5-a04d-1e76524943b8@linux.dev> (raw)
In-Reply-To: <ajjZkRxoh2F3vUAS@blinky>

On 6/21/26 11:43 PM, Charlie Jenkins wrote:
> On Mon, Jun 08, 2026 at 11:01:21PM -0700, Atish Patra wrote:
>> From: Kaiwen Xue <kaiwenx@rivosinc.com>
>>
>> This adds the scountinhibit CSR definition and S-mode accessible hpmevent
>> bits defined by smcdeleg/ssccfg. scountinhibit allows S-mode to start/stop
>> counters directly from S-mode without invoking SBI calls to M-mode. It is
>> also used to figure out the counters delegated to S-mode by the M-mode as
>> well.
>>
>> Signed-off-by: Kaiwen Xue <kaiwenx@rivosinc.com>
>> Reviewed-by: Clément Léger <cleger@rivosinc.com>
>> ---
>>   arch/riscv/include/asm/csr.h | 26 ++++++++++++++++++++++++++
>>   1 file changed, 26 insertions(+)
>>
>> diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
>> index b4551a6cf7cb..26cb78dee2fd 100644
>> --- a/arch/riscv/include/asm/csr.h
>> +++ b/arch/riscv/include/asm/csr.h
>> @@ -241,6 +241,31 @@
>>   #define SMSTATEEN0_HSENVCFG		(_ULL(1) << SMSTATEEN0_HSENVCFG_SHIFT)
>>   #define SMSTATEEN0_SSTATEEN0_SHIFT	63
>>   #define SMSTATEEN0_SSTATEEN0		(_ULL(1) << SMSTATEEN0_SSTATEEN0_SHIFT)
>> +/* HPMEVENT bits. These are accessible in S-mode via Smcdeleg/Ssccfg */
>> +#ifdef CONFIG_64BIT
>> +#define HPMEVENT_OF			(BIT_ULL(63))
>> +#define HPMEVENT_MINH			(BIT_ULL(62))
>> +#define HPMEVENT_SINH			(BIT_ULL(61))
>> +#define HPMEVENT_UINH			(BIT_ULL(60))
>> +#define HPMEVENT_VSINH			(BIT_ULL(59))
>> +#define HPMEVENT_VUINH			(BIT_ULL(58))
>> +#else
>> +#define HPMEVENTH_OF			(BIT_ULL(31))
>> +#define HPMEVENTH_MINH			(BIT_ULL(30))
>> +#define HPMEVENTH_SINH			(BIT_ULL(29))
>> +#define HPMEVENTH_UINH			(BIT_ULL(28))
>> +#define HPMEVENTH_VSINH			(BIT_ULL(27))
>> +#define HPMEVENTH_VUINH			(BIT_ULL(26))
> Since these are rv32 bits for a 32-bit register, I think these should be
> BIT() instead of BIT_ULL()
>
>> +
>> +#define HPMEVENT_OF			(HPMEVENTH_OF << 32)
>> +#define HPMEVENT_MINH			(HPMEVENTH_MINH << 32)
>> +#define HPMEVENT_SINH			(HPMEVENTH_SINH << 32)
>> +#define HPMEVENT_UINH			(HPMEVENTH_UINH << 32)
>> +#define HPMEVENT_VSINH			(HPMEVENTH_VSINH << 32)
>> +#define HPMEVENT_VUINH			(HPMEVENTH_VUINH << 32)
> These definitions are identical to the rv64 ones, can these be removed
> and can you move the rv64 definitions to be global?

Good catch. Will fix this and the above in v8.

> - Charlie
>
>> +#endif
>> +
>> +#define SISELECT_SSCCFG_BASE		0x40
>>   
>>   /* mseccfg bits */
>>   #define MSECCFG_PMM			ENVCFG_PMM
>> @@ -322,6 +347,7 @@
>>   #define CSR_SCOUNTEREN		0x106
>>   #define CSR_SENVCFG		0x10a
>>   #define CSR_SSTATEEN0		0x10c
>> +#define CSR_SCOUNTINHIBIT	0x120
>>   #define CSR_SSCRATCH		0x140
>>   #define CSR_SEPC		0x141
>>   #define CSR_SCAUSE		0x142
>>
>> -- 
>> 2.53.0-Meta
>>
>>
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