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Message-ID: <CAAhSdy1BB=-FR_hx2mObDeWD+z2WzaVdZeiO9inmGPXasMcCTg@mail.gmail.com>
Date: Wed, 12 Feb 2020 10:23:30 +0530
From: Anup Patel <anup@...infault.org>
To: Atish Patra <atish.patra@....com>
Cc: "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
Albert Ou <aou@...s.berkeley.edu>,
Allison Randal <allison@...utok.net>,
Borislav Petkov <bp@...e.de>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Jason Cooper <jason@...edaemon.net>,
Kees Cook <keescook@...omium.org>,
linux-riscv <linux-riscv@...ts.infradead.org>,
Mao Han <han_mao@...ky.com>, Marc Zyngier <maz@...nel.org>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Michael Ellerman <mpe@...erman.id.au>,
Mike Rapoport <rppt@...ux.ibm.com>,
Palmer Dabbelt <palmer@...belt.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Thomas Gleixner <tglx@...utronix.de>,
Vincent Chen <vincent.chen@...ive.com>
Subject: Re: [PATCH v8 08/11] RISC-V: Add SBI HSM extension
On Wed, Feb 12, 2020 at 7:22 AM Atish Patra <atish.patra@....com> wrote:
>
> SBI specification defines HSM extension that allows to start/stop a hart
> by a supervisor anytime. The specification is available at
>
> https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc
>
> Implement SBI HSM extension.
I think this PATCH needs to be further broken down.
There are three distinct changes here:
1. Exporting sbi_err_map_linux_errno() function
arch/riscv/kernel/sbi.c
arch/riscv/include/asm/sbi.h
2. SBI HSM defines
arch/riscv/include/asm/sbi.h
3. SBI HSM helper functions (which are mostly static functions)
arch/riscv/kernel/Makefile
arch/riscv/kernel/cpu_ops_sbi.c
We need separate patches for point1 and point2 above.
Also, point3 can be part of current PATCH9.
Regards,
Anup
>
> Signed-off-by: Atish Patra <atish.patra@....com>
> ---
> arch/riscv/include/asm/sbi.h | 15 +++++++++++
> arch/riscv/kernel/Makefile | 3 +++
> arch/riscv/kernel/cpu_ops_sbi.c | 48 +++++++++++++++++++++++++++++++++
> arch/riscv/kernel/sbi.c | 3 ++-
> 4 files changed, 68 insertions(+), 1 deletion(-)
> create mode 100644 arch/riscv/kernel/cpu_ops_sbi.c
>
> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
> index d55d8090ab5c..0981a0c97eda 100644
> --- a/arch/riscv/include/asm/sbi.h
> +++ b/arch/riscv/include/asm/sbi.h
> @@ -26,6 +26,7 @@ enum sbi_ext_id {
> SBI_EXT_TIME = 0x54494D45,
> SBI_EXT_IPI = 0x735049,
> SBI_EXT_RFENCE = 0x52464E43,
> + SBI_EXT_HSM = 0x48534D,
> };
>
> enum sbi_ext_base_fid {
> @@ -56,6 +57,19 @@ enum sbi_ext_rfence_fid {
> SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID,
> };
>
> +enum sbi_ext_hsm_fid {
> + SBI_EXT_HSM_HART_START = 0,
> + SBI_EXT_HSM_HART_STOP,
> + SBI_EXT_HSM_HART_STATUS,
> +};
> +
> +enum sbi_hsm_hart_status {
> + SBI_HSM_HART_STATUS_AVAILABLE = 0,
> + SBI_HSM_HART_STATUS_NOT_AVAILABLE,
> + SBI_HSM_HART_STATUS_START_PENDING,
> + SBI_HSM_HART_STATUS_STOP_PENDING,
> +};
> +
> #define SBI_SPEC_VERSION_DEFAULT 0x1
> #define SBI_SPEC_VERSION_MAJOR_SHIFT 24
> #define SBI_SPEC_VERSION_MAJOR_MASK 0x7f
> @@ -130,6 +144,7 @@ static inline unsigned long sbi_minor_version(void)
> {
> return sbi_spec_version & SBI_SPEC_VERSION_MINOR_MASK;
> }
> +int sbi_err_map_linux_errno(int err);
> #else /* CONFIG_RISCV_SBI */
> /* stubs for code that is only reachable under IS_ENABLED(CONFIG_RISCV_SBI): */
> void sbi_set_timer(uint64_t stime_value);
> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
> index f81a6ff88005..a0be34b96846 100644
> --- a/arch/riscv/kernel/Makefile
> +++ b/arch/riscv/kernel/Makefile
> @@ -44,5 +44,8 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event.o
> obj-$(CONFIG_PERF_EVENTS) += perf_callchain.o
> obj-$(CONFIG_HAVE_PERF_REGS) += perf_regs.o
> obj-$(CONFIG_RISCV_SBI) += sbi.o
> +ifeq ($(CONFIG_RISCV_SBI), y)
> +obj-$(CONFIG_SMP) += cpu_ops_sbi.o
> +endif
>
> clean:
> diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
> new file mode 100644
> index 000000000000..9bdb60e0a4df
> --- /dev/null
> +++ b/arch/riscv/kernel/cpu_ops_sbi.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * HSM extension and cpu_ops implementation.
> + *
> + * Copyright (c) 2020 Western Digital Corporation or its affiliates.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/mm.h>
> +#include <asm/sbi.h>
> +#include <asm/smp.h>
> +
> +static int sbi_hsm_hart_stop(void)
> +{
> + struct sbiret ret;
> +
> + ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STOP, 0, 0, 0, 0, 0, 0);
> +
> + if (ret.error)
> + return sbi_err_map_linux_errno(ret.error);
> + else
> + return 0;
> +}
> +
> +static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr,
> + unsigned long priv)
> +{
> + struct sbiret ret;
> +
> + ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
> + hartid, saddr, priv, 0, 0, 0);
> + if (ret.error)
> + return sbi_err_map_linux_errno(ret.error);
> + else
> + return 0;
> +}
> +
> +static int sbi_hsm_hart_get_status(unsigned long hartid)
> +{
> + struct sbiret ret;
> +
> + ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STATUS,
> + hartid, 0, 0, 0, 0, 0);
> + if (ret.error)
> + return sbi_err_map_linux_errno(ret.error);
> + else
> + return ret.value;
> +}
> diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
> index cd0f68aeac70..45ad49269f2c 100644
> --- a/arch/riscv/kernel/sbi.c
> +++ b/arch/riscv/kernel/sbi.c
> @@ -47,7 +47,7 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
> }
> EXPORT_SYMBOL(sbi_ecall);
>
> -static int sbi_err_map_linux_errno(int err)
> +int sbi_err_map_linux_errno(int err)
> {
> switch (err) {
> case SBI_SUCCESS:
> @@ -64,6 +64,7 @@ static int sbi_err_map_linux_errno(int err)
> return -ENOTSUPP;
> };
> }
> +EXPORT_SYMBOL(sbi_err_map_linux_errno);
>
> #ifdef CONFIG_RISCV_SBI_V01
> /**
> --
> 2.24.0
>
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