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Date: Thu, 28 Dec 2023 17:44:50 -0800 (PST)
Subject:     Re: [v1 04/10] RISC-V: Add SBI PMU snapshot definitions
In-Reply-To: <20231218104107.2976925-5-atishp@rivosinc.com>
CC: linux-kernel@vger.kernel.org, Atish Patra <atishp@rivosinc.com>,
  anup@brainfault.org, aou@eecs.berkeley.edu, alexghiti@rivosinc.com, ajones@ventanamicro.com,
  atishp@atishpatra.org, Conor Dooley <conor.dooley@microchip.com>, guoren@kernel.org, uwu@icenowy.me,
  kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-riscv@lists.infradead.org,
  Mark Rutland <mark.rutland@arm.com>, Paul Walmsley <paul.walmsley@sifive.com>, Will Deacon <will@kernel.org>
From: Palmer Dabbelt <palmer@dabbelt.com>
To: Atish Patra <atishp@rivosinc.com>
Message-ID: <mhng-bc357c81-f43a-40e2-b4ac-f9c462e4c006@palmer-ri-x1c9a>
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On Mon, 18 Dec 2023 02:41:01 PST (-0800), Atish Patra wrote:
> SBI PMU Snapshot function optimizes the number of traps to
> higher privilege mode by leveraging a shared memory between the S/VS-mode
> and the M/HS mode. Add the definitions for that extension and new error
> codes.
>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> ---
>  arch/riscv/include/asm/sbi.h | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> index f3eeca79a02d..a24bc4fa34ff 100644
> --- a/arch/riscv/include/asm/sbi.h
> +++ b/arch/riscv/include/asm/sbi.h
> @@ -122,6 +122,7 @@ enum sbi_ext_pmu_fid {
>  	SBI_EXT_PMU_COUNTER_STOP,
>  	SBI_EXT_PMU_COUNTER_FW_READ,
>  	SBI_EXT_PMU_COUNTER_FW_READ_HI,
> +	SBI_EXT_PMU_SNAPSHOT_SET_SHMEM,
>  };
>
>  union sbi_pmu_ctr_info {
> @@ -138,6 +139,13 @@ union sbi_pmu_ctr_info {
>  	};
>  };
>
> +/* Data structure to contain the pmu snapshot data */
> +struct riscv_pmu_snapshot_data {
> +	uint64_t ctr_overflow_mask;
> +	uint64_t ctr_values[64];
> +	uint64_t reserved[447];
> +};
> +
>  #define RISCV_PMU_RAW_EVENT_MASK GENMASK_ULL(47, 0)
>  #define RISCV_PMU_RAW_EVENT_IDX 0x20000
>
> @@ -234,9 +242,11 @@ enum sbi_pmu_ctr_type {
>
>  /* Flags defined for counter start function */
>  #define SBI_PMU_START_FLAG_SET_INIT_VALUE (1 << 0)
> +#define SBI_PMU_START_FLAG_INIT_FROM_SNAPSHOT BIT(1)
>
>  /* Flags defined for counter stop function */
>  #define SBI_PMU_STOP_FLAG_RESET (1 << 0)
> +#define SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT BIT(1)
>
>  enum sbi_ext_dbcn_fid {
>  	SBI_EXT_DBCN_CONSOLE_WRITE = 0,
> @@ -259,6 +269,7 @@ enum sbi_ext_dbcn_fid {
>  #define SBI_ERR_ALREADY_AVAILABLE -6
>  #define SBI_ERR_ALREADY_STARTED -7
>  #define SBI_ERR_ALREADY_STOPPED -8
> +#define SBI_ERR_NO_SHMEM	-9
>
>  extern unsigned long sbi_spec_version;
>  struct sbiret {

Acked-by: Palmer Dabbelt <palmer@rivosinc.com>